Identification of Polymorphism in the MC1R Gene and Its Association with the Melanin Content in Feathers of Chinese Yellow Quails

MC1R plays a crucial role in controlling the type of melanin synthesized in the melanocytes, which greatly affects plumage color in birds. One g.16796362G/T SNP was found in the MC1R gene coding region, which caused a Met120Ile mutation in the amino acid sequence. The Met120Ile mutation was located in the third transmembrane domain of the MC1R protein and decreased protein stability. The g.16796362G/T locus achieved medium polymorphism and had significant association with feather melanin content in Chinese yellow quails. The contents of total melanin and pheomelanin with AA genotype were significant lower than those with AB or BB genotypes in skin tissues, while the expression levels of MC1R mRNA had no significant difference in feathers with different genotypes. This experiment indicated that the Met120Ile mutation could affect the function of the MC1R protein and change the biosynthesis of melanin in Chinese yellow quails.(AU)

Melanomas em cães no Sertão do Nordeste do Brasil - epidemiologia, fatores de risco e achados clinicopatológicos / Melanoma in dogs in the backlands of Northeastern Brazil - epidemiology, risk factors and clinicopathological findings

Background: Melanoma is a malignant neoplasm that arises from melanocytes and malanoblasts. It is also more frequently reported in dogs than in other species. They may arise from melanocytes in the skin, on the surfaces of the mucous membranes, and eyes. The aim of this study was to describe the epidemiological aspects, risk factors and clinicopathological findings of melanoma in dogs in the backlands, northeastern Brazil. Materials, Methods & Results: A retrospective study was carried out in all biopsy samples and necropsy examinations of dogs, from January 2003 to December 2021, at the Animal Pathology Laboratory of the Federal University of Campina Grande, Patos, Paraiba, northeastern Brazil. Epidemiological data, clinical signs, and gross lesions were reviewed from the diagnostic laboratory reports. Samples of the skin, lymph nodes, central nervous system and organs of the thoracic and abdominal cavities were fixed in 10% buffered formalin, processed routinely for histopathology, embedded in paraffin wax, cut into 4 µm sections, and stained with hematoxylin and eosin (HE). Histological sections were also submitted to immunohistochemistry with the primary antibody anti-Melan A. Of the 4717 records found, 1158 (24.5%) were diagnosed with neoplasms, of which 48 (4.14%) cases were of melanoma. Of this total, 28 (58.3%) dogs were elderly, 19 (39.6%) were adults, and 1 (2.1%) was young. Mixed breed animals were the most affected (42.6%), followed by the pinscher breed (19.1%). According to the anatomical region, the most affected site was the skin (38/53=71.7%), followed by the oral cavity (12/53=22.65%) and the eyes (3/53=5.7%). Grossly, the skin lesions were characterized by exophytic and usually blackened, sometimes irregular and firm, nodules. At cut, they had a smooth, compact and blackened surface. Lesions in the oral cavity were characterized by blackened, irregular and infiltrating nodules or masses. The ocular lesions were always unilateral and were characterized by an enlarged and diffusely blackened eyeball, with areas of ulceration and subversion of tissue architecture. In 5 animals there was more than one anatomical site affected, totaling 53 lesions. In 9 (17%) cases, metastases were identified, 8 in regional lymph nodes and 1 in the lung. Histopathology showed a densely non-encapsulated, poorly delimited, expansive and infiltrative neoplasm, composed of neoplastic cells arranged in islands or nests and supported by fibrovascular stroma, containing a variable amount of brownish pigment (melanin). Immunohistochemistry showed strong immunostaining of the neoplastic cells in brown by the anti-Melan A antibody. Discussion: The diagnosis of melanoma was established based on epidemiological, clinical, anatomopathological, and immunohistochemical findings. Gender is not a predisposing factor, and although there was no statistically significant relationship, males were more affected. Senescence is a conditioning risk factor. Elderly animals were more affected (P < 0.0001) than adult ones, with OR = 4.38; and young ones (P = 0.0051), with OR = 12.65. Some breeds, especially those with marked skin pigmentation, were more affected, however the most affected ones in this survey were pinscher and poodle. Cutaneous melanoma accounted for almost 72% of cases, contesting recent studies where oral cavity melanoma was more frequent. Therefore, it is believed that the climatic conditions of the backlands sub-region, in northeastern Brazil, associated with the individual characteristics of the dogs, are involved in the development of these neoplasms, since the climate is predominantly dry, with high temperatures throughout the year, with maximums that can reach 40ºC, favoring the exposure to high incidence of ultraviolet radiation.

Cryosurgery using dimethyl ether in the treatment of pigmentary keratitis in pug dogs / Criocirurgia usando o dimethyl ether no tratamento da ceratite pigmentar em cães da raça Pug

Corneal pigmentation and vascularization eventually result in blindness in dogs. Pigmentary keratitis describes a relatively common presentation comprising the deposition of melanin in the cornea and conjunctival surface associated with chronic inflammation. Cryosurgery is indicated as a treatment for pigmentary keratitis in dogs. Due to melanocytes sensitivity to cold, cryosurgery is a viable treatment for severe refractory corneal pigmentation. The aim of this work was to evaluate the use of dimethyl ether in the treatment of pigmentary keratitis in 14 eyes of seven Pug dogs. Follow-up occurred after 30 days in four animals and six months in three animals. In all treated animals, there was a reduction in corneal pigmentation. Cryosurgery causes intracellular and extracellular ice crystal formation and other mechanisms that result in rupture and death of the melanocytes. The technique used was easy to perform, has a low cryogen cost and has few undesirable or serious side effects. However, after 30 days repigmentation occured in treated patients. Cryosurgery shows good results in the first four weeks, but partial recurrence occurred in all cases.

A pigmentação e a vascularização da córnea eventualmente resultam em cegueira em cães. A ceratite pigmentar é descrita com uma apresentação relativamente comum que compreende a deposição de melanina na córnea e na superfície conjuntival associada à inflamação crônica. A criocirurgia é indicada como tratamento para ceratite pigmentar em cães. Devido à sensibilidade dos melanócitos ao frio, a criocirurgia é um tratamento viável para pigmentação corneana refratária grave. O objetivo deste trabalho foi avaliar o uso do éter dimetílico no tratamento da ceratite pigmentar em 14 olhos de sete cães da raça Pug. O acompanhamento foi de 30 dias em quatro animais e seis meses em três animais. Em todos os animais tratados, houve redução da pigmentação da córnea. A criocirurgia causa a formação de cristais de gelo intracelular e extracelular e outros mecanismos que resultam na ruptura e morte dos melanócitos. A técnica utilizada foi de fácil execução, baixo custo de criogenia e poucos efeitos colaterais indesejáveis ou graves. No entanto, após 30 dias, ocorreu repigmentação nos pacientes tratados. A criocirurgia apresenta bons resultados nas primeiras quatro semanas, mas ocorreu recidiva parcial em todos os casos.

Licorice zinc suppresses melanogenesis via inhibiting the activation of P38MAPK and JNK signaling pathway in Balb/c mice skin

Purpose: The active melanocytes in the skin were affected by hormones and ultraviolet (UV) irradiation. Licorice zinc has a whitening effect, which may have a prominent potential in the treatment of pigmented skin disease. Methods: Modeling chloasma C57BL/6J mice by daily progesterone injection (15 mg/kg) and ultraviolet B (UVB) irradiation (λ = 312 nm, 2 h/day) for 30 days. Then, mice were given 0.65, 1.3, and 2.6 (g/kg) of licorice zinc and tranexamic acid 250 mg daily by oral administration for 14 days, respectively. Hematoxylin and eosin and Fontana-Masson staining, and Western blotting (WB) were performed to test the inhibitory of melanogenesis and activation of c-Jun-N-terminal (JNK)/p38 mitogen-activated protein kinases (MAPK) for licorice zinc. Melanogenesis was induced by α-melanocyte-stimulating hormone in vitro. Cell counting kit-8, melanin content determination, and WB were performed to verify the inhibitory effect of licorice zinc on melanogenesis. Results: The present study showed that licorice zinc decreased melanin formation, cutaneous tissue injury, and the phosphorylation of JNK and P38MAPK, which was caused by UVB irradiation in vivo. In vitro, licorice zinc showed opposite effects from JNK/p38 activator. Meanwhile, tyrosinase-related protein-1, tyrosinase, and microphthalmia-associated transcription factor were decreased too. Conclusions: Licorice zinc induced a decrease in melanin synthesis by inhibiting the JNK and the P38MAPK signaling pathway, suggesting licorice zinc is a potential agent of anti-chloasma.

Primary perianal malignant melanoma in a dog - combination therapy

Background: Melanocytic neoplasm can arise from melanocytes in any location of the body. Malignant melanoma (MM)has a poor prognosis in dogs and presence of lymphvascular invasion, distant metastasis, or mitotic activity present prognostic value. Primary melanoma affecting the gastrointestinal tract has been rarely reported in veterinary literature, thusthe prognosis affecting gastrointestinal tract is unknown. Electrochemotherapy (ECT) is an effective local treatment whichcombines chemotherapeutic drugs mainly bleomycin or cisplatin followed by the delivery of permeabilizing electricalpulses However, other hydrophilic drugs seem to present an increase cytotoxic effect such as carboplatin.Case: A 9-year-old mixed-breed neutered dog was referred to a private clinic with a mass in the perianal region diagnosedas perianal melanoma. No metastasis was observed on abdominal ultrasound nor chest x-ray (3 views). Clinical signs notedwere tenesmus, hemorrhagic discharge, weight loss and hyporexia. Considering the tumor volume (16.0 x 10.0 cm), a neoadjuvant ECT session was proposed. The authors opted for carboplatin (300 mg/m2, intravenously), administered over 20min and cisplatin intratumorally (1 mg/cm3, equivalent to 1 mL/1cm3 total volume 20 mL) administered in the upper partsof the mass that could be reached while avoiding drug leakage. After administration, sequences of eight biphasic pulses,(100 microseconds), with a voltage ranging from 650-1,000V/cm (pulse generator Onkodisruptor®) using a hexagonal/single pair and plate electrode were delivered. At day 30th, a partial response was observed accordingly to RECIST system,with tumor size of 5.0 x 5.0 cm (65.4 cm3). A second ECT session was performed with the same previous protocol, butwith a decreased dosage of carboplatin (240 mg/m2 consistent with 20% reduction) due to adverse effects in the first session, resulting in stable disease at day 60th (30 days after second ECT). Then...

Primary perianal malignant melanoma in a dog - combination therapy

Background: Melanocytic neoplasm can arise from melanocytes in any location of the body. Malignant melanoma (MM)has a poor prognosis in dogs and presence of lymphvascular invasion, distant metastasis, or mitotic activity present prognostic value. Primary melanoma affecting the gastrointestinal tract has been rarely reported in veterinary literature, thusthe prognosis affecting gastrointestinal tract is unknown. Electrochemotherapy (ECT) is an effective local treatment whichcombines chemotherapeutic drugs mainly bleomycin or cisplatin followed by the delivery of permeabilizing electricalpulses However, other hydrophilic drugs seem to present an increase cytotoxic effect such as carboplatin.Case: A 9-year-old mixed-breed neutered dog was referred to a private clinic with a mass in the perianal region diagnosedas perianal melanoma. No metastasis was observed on abdominal ultrasound nor chest x-ray (3 views). Clinical signs notedwere tenesmus, hemorrhagic discharge, weight loss and hyporexia. Considering the tumor volume (16.0 x 10.0 cm), a neoadjuvant ECT session was proposed. The authors opted for carboplatin (300 mg/m2, intravenously), administered over 20min and cisplatin intratumorally (1 mg/cm3, equivalent to 1 mL/1cm3 total volume 20 mL) administered in the upper partsof the mass that could be reached while avoiding drug leakage. After administration, sequences of eight biphasic pulses,(100 microseconds), with a voltage ranging from 650-1,000V/cm (pulse generator Onkodisruptor®) using a hexagonal/single pair and plate electrode were delivered. At day 30th, a partial response was observed accordingly to RECIST system,with tumor size of 5.0 x 5.0 cm (65.4 cm3). A second ECT session was performed with the same previous protocol, butwith a decreased dosage of carboplatin (240 mg/m2 consistent with 20% reduction) due to adverse effects in the first session, resulting in stable disease at day 60th (30 days after second ECT). Then...(AU)

Melanose talâmica em caprinos / Thalamic melanosis in goats

Background: Melanosis is a blackened pigmentation resulting from the accumulation of melanocytes in tissues that are not normally pigmented. This change in the color of the organs occurs due to the agglomeration of melanocytes originating from abnormal migration during embryogenesis and does not cause dysfunction to the affected organ. Although melanosis frequently occurs in several species and affects several organs such as the brain and spinal cord leptomeninges, involvement in the thalamus region is unusual. The objective of this work was to report 2 cases of thalamic melanosis in goats, determining the pathological and histochemical aspects that assist in the diagnosis of this condition. Cases: Two cases of thalamic melanosis in goats were diagnosed. In both cases, the animals had no nervous history disease and clinical signs. The cause of death in cases 1 and 2 was established based on anatomopathological findings and clinical signs being diagnosed with mycoplasmosis and asphyxia, respectively. After fixing and making cross-sections of the brain, a focal lengthy blackened area was observed on the thalamus surface in both cases. Microscopically, lesions in the brain were similar in both cases and exclusively affected the thalamus. These cells had abundant cytoplasm, well delimited with brownish granular pigment. The nuclei were difficult to visualize and in some cells, it was rounded, well-defined, morphologically compatible with melanocytes. Melanocytes were mainly distributed around neurons and often distended the perivascular space of multiple blood vessels. In Fontana Masson staining, the granules in the cytoplasm of these cells stained strongly black. The Prussian Blue, Periodic Acid- Schiff's, Von Kossa, and Giemsa stains were negative, and the pigment remained brown. In the unstained slides, assembled after the deparaffinization and clarification process, it was observed the permanence of cells with blackish-brown pigment in the cytoplasm. In immunohistochemistry, strong immunostaining of pigmented cells with the Anti-MelanA antibodies was observed in both cases. Discussion: The diagnosis of thalamic melanosis in goats was carried out based on the characteristic pathological findings, in which melanin pigments were demonstrated and identified through HE, Fontana-Masson staining, and unstained slides and confirmed by the IHC. The use of complementary histochemical techniques was fundamental for the classification of the pigment as melanin, demonstrating to be an accessible and reliable tool for the diagnosis of pathological processes that lead to the accumulation of pigments and or material in the tissues. The occurrence of melanin in the thalamus may be associated with a failure in the migration of melanoblasts, which would go to the optical pathways or to the thalamus. This erratic migration of melanoblasts can be explained by the fact that the forebrain is the embryogenic origin of the optic and diencephalon pathways. Macroscopically, thalamic melanosis must be differentiated mainly from neoplastic processes such as melanoma and hemangiosarcoma, pigmented fungus infections, Phalaris angusta poisoning, listeriosis, neurocutaneous melanosis, and neuromelanin. It was concluded that thalamic melanosis is an uncommon alteration in goats and although it has been diagnosed as an incidental necropsy finding, should be included in the differential diagnosis of diseases that affect the central nervous system, especially those that have a color change associated with the deposition of pigments in the tissues.

Ultrastructural and morphometric description of the ear skin and cartilage of two South American wild histricognate rodents (Dasyprocta leporina and Galea spixii) / Descrição ultraestrutural e morfométrica da pele e cartilagem auricular de dois roedores histricognatos silvestres da América do Sul (Dasyprocta leporina e Galea spixii)

Skin and cartilage have been the main source for the recovery of somatic cells to be used in conservation strategies in wild mammals. In this sense, an important step for the cryopreservation of these samples is to recognize the properties of the skin and cartilage. Thus, knowing that the skin may differ among species and aiming to contribute to the establishment of cryobanks, the study examined the differences in the ear skin and cartilage of wild rodents from South America, agouti (Dasyprocta leporina) and spix's yellow-toothed cavy (Galea spixii). Ultrastructural and quantitative methods were used to measure skin and cartilage thickness, density of collagen and elastic fibers, cell type number and distribution, and proliferative activity. Although ultrastructural analysis revealed a similar pattern between species, morphometric analysis of the skin and cartilage showed differences between agoutis and cavies regarding thickness of epidermis layers (corneum: 5.3±2.5μm vs. 3.9±0.6μm; intermediate: 16.4±6.2μm vs. 23.4±8.1μm; basal: 9.9±2.1μm vs. 4.8±0.5μm), dermis (183.1±44.0μm vs. 258.2±22.9μm), total skin (211.8±46.0μm vs. 290.3±23.7μm) and perichondrium (27.6±6.1μm vs. 10.5±1.8μm). A greater number of epidermal cells (61.7±15.2 vs. 24.8±7.6) and chondrocytes (32.7±9.0 vs. 27.5±4.7) were observed in agouti, while the cavy presented a greater number of melanocytes (12.6±4.7 vs. 29.9±6.2), keratinocytes (14.7±4.2 vs. 29.8±7.6), and fibroblasts (103.6±24.7 vs. 112.2±11.3). Moreover, a higher percentage of collagen fibers and proliferative activity was observed in the skin of cavies, when compared to the skin of agoutis. Therefore, there are differences between agouti and cavy for ear skin and cartilage, requiring the establishment of species-specific cryopreservation protocols.(AU)

A pele e cartilagem têm sido uma importante fonte de recuperação de células somáticas a serem utilizadas em estratégias de conservação em mamíferos silvestres. Nesse contexto, uma importante etapa para criopreservação é conhecer, inicialmente, as propriedades que compõem a pele e cartilagem. Sabendo, então, que a pele pode diferir-se entre espécies e com o objetivo de contribuir para o estabelecimento de criobancos, o estudo evidenciou as diferenças da pele e da cartilagem do pavilhão auricular apical de cutias (Dasyprocta leporina) e preás (Galea spixii) que são roedores silvestres presentes na América do Sul. Para tanto, métodos ultraestruturais e quantitativos foram utilizados para mensurar a espessura da pele e da cartilagem, densidade de fibras colágenas e elásticas, número e distribuição dos tipos celulares e atividade proliferativa. Embora as propriedades ultraestruturais em cutias e preás tenham se mostrado semelhantes, avaliações acerca da morfometria da pele e da cartilagem demonstrou diferenças, especialmente nas camadas epidérmicas (córnea: 5,3±2,5μm vs. 3,9±0,6μm; espinhosa: 16,4±6,2μm vs. 23,4±8,1μm; basal: 9,9±2,1μm vs. 4,8±0,5μm), derme (183,1±44,0μm vs. 258,2±22,9μm), pele total (211,8±46,0μm vs. 290,3±23,7μm) e pericôndrio (27,6±6,1μm vs. 10,5±1,8μm). Além disso, um número maior de células epidérmicas (61,7±15,2 vs. 24,8±7,6) e condrócitos (32,7±9,0 vs. 27,5±4,7) foram observados em cutias, enquanto em preás um maior número de melanócitos (12,6±4,7 vs. 29,9±6,2), queratinócitos (14,7±4,2 vs. 29,8±7,6) e fibroblastos (103,6±24,7 vs. 112,2±11,3) foram evidenciados. Ainda, em preás, uma maior porcentagem de fibras colágenas e da atividade proliferativa foram observadas quando comparadas a pele de cutias. Portanto, existem diferenças entre cutias e preás para pele e cartilagem do pavilhão auricular, exigindo desta forma um estabelecimento de protocolos de criopreservação específica para cada uma destas espécies.(AU)

Ultrastructural and morphometric description of the ear skin and cartilage of two South American wild histricognate rodents (Dasyprocta leporina and Galea spixii) / Descrição ultraestrutural e morfométrica da pele e cartilagem auricular de dois roedores histricognatos silvestres da América do Sul (Dasyprocta leporina e Galea spixii)

Skin and cartilage have been the main source for the recovery of somatic cells to be used in conservation strategies in wild mammals. In this sense, an important step for the cryopreservation of these samples is to recognize the properties of the skin and cartilage. Thus, knowing that the skin may differ among species and aiming to contribute to the establishment of cryobanks, the study examined the differences in the ear skin and cartilage of wild rodents from South America, agouti (Dasyprocta leporina) and spix's yellow-toothed cavy (Galea spixii). Ultrastructural and quantitative methods were used to measure skin and cartilage thickness, density of collagen and elastic fibers, cell type number and distribution, and proliferative activity. Although ultrastructural analysis revealed a similar pattern between species, morphometric analysis of the skin and cartilage showed differences between agoutis and cavies regarding thickness of epidermis layers (corneum: 5.3±2.5μm vs. 3.9±0.6μm; intermediate: 16.4±6.2μm vs. 23.4±8.1μm; basal: 9.9±2.1μm vs. 4.8±0.5μm), dermis (183.1±44.0μm vs. 258.2±22.9μm), total skin (211.8±46.0μm vs. 290.3±23.7μm) and perichondrium (27.6±6.1μm vs. 10.5±1.8μm). A greater number of epidermal cells (61.7±15.2 vs. 24.8±7.6) and chondrocytes (32.7±9.0 vs. 27.5±4.7) were observed in agouti, while the cavy presented a greater number of melanocytes (12.6±4.7 vs. 29.9±6.2), keratinocytes (14.7±4.2 vs. 29.8±7.6), and fibroblasts (103.6±24.7 vs. 112.2±11.3). Moreover, a higher percentage of collagen fibers and proliferative activity was observed in the skin of cavies, when compared to the skin of agoutis. Therefore, there are differences between agouti and cavy for ear skin and cartilage, requiring the establishment of species-specific cryopreservation protocols.(AU)

A pele e cartilagem têm sido uma importante fonte de recuperação de células somáticas a serem utilizadas em estratégias de conservação em mamíferos silvestres. Nesse contexto, uma importante etapa para criopreservação é conhecer, inicialmente, as propriedades que compõem a pele e cartilagem. Sabendo, então, que a pele pode diferir-se entre espécies e com o objetivo de contribuir para o estabelecimento de criobancos, o estudo evidenciou as diferenças da pele e da cartilagem do pavilhão auricular apical de cutias (Dasyprocta leporina) e preás (Galea spixii) que são roedores silvestres presentes na América do Sul. Para tanto, métodos ultraestruturais e quantitativos foram utilizados para mensurar a espessura da pele e da cartilagem, densidade de fibras colágenas e elásticas, número e distribuição dos tipos celulares e atividade proliferativa. Embora as propriedades ultraestruturais em cutias e preás tenham se mostrado semelhantes, avaliações acerca da morfometria da pele e da cartilagem demonstrou diferenças, especialmente nas camadas epidérmicas (córnea: 5,3±2,5μm vs. 3,9±0,6μm; espinhosa: 16,4±6,2μm vs. 23,4±8,1μm; basal: 9,9±2,1μm vs. 4,8±0,5μm), derme (183,1±44,0μm vs. 258,2±22,9μm), pele total (211,8±46,0μm vs. 290,3±23,7μm) e pericôndrio (27,6±6,1μm vs. 10,5±1,8μm). Além disso, um número maior de células epidérmicas (61,7±15,2 vs. 24,8±7,6) e condrócitos (32,7±9,0 vs. 27,5±4,7) foram observados em cutias, enquanto em preás um maior número de melanócitos (12,6±4,7 vs. 29,9±6,2), queratinócitos (14,7±4,2 vs. 29,8±7,6) e fibroblastos (103,6±24,7 vs. 112,2±11,3) foram evidenciados. Ainda, em preás, uma maior porcentagem de fibras colágenas e da atividade proliferativa foram observadas quando comparadas a pele de cutias. Portanto, existem diferenças entre cutias e preás para pele e cartilagem do pavilhão auricular, exigindo desta forma um estabelecimento de protocolos de criopreservação específica para cada uma destas espécies.(AU)

Treatment of limbal melanocytoma with full excision and a fresh homologous corneoscleral graft in a dog

Background: Limbal melanoma has been diagnosed in dogs and due to progression may cause vision loss and eyeballremoval. Definitive diagnosis is made through histopathological examination. Therapeutic options include full thicknessresection and repair by homologous corneal tissue, synthetic graft material, and enucleation. In this report, we describe acase of limbal melanocitoma in a dog that has been treated successfully with fresh homologous corneoscleral graft.Case: A 5-year-old female Labrador was referred to the Ophthalmology Veterinary Section of the Federal University ofRio Grande do Sul (UFRGS), Porto Alegre, Brazil, with a history of a pigmented mass located on the left eye. Ophthalmicexamination revealed a pigmented mass located at the left temporal limbus with corneal involvement. Surgical excisionfollowed by reconstruction using fresh homologous corneoscleral was recommended. The patient was premedicated withacepromazine (0.05 mg/kg, IM) and meperidine (20 mg/kg, IM). Anaesthesia was induced with propofol (10 mg/kg, IV)and maintained with isoflurane. Atracurium (0.2 mg/kg, IV) was administered to maintain a central eye position. The massand a free margin were removed by full-thickness corneoscleral resection. A corneoscleral graft was harvested from a dogthat had been euthanised for reasons unrelated to this study and sutured with 9-0 polyglactin 910 using a simple interruptedpattern. The mass was immediately fixed in 10% neutral buffered formalin and submitted for histological sectioning androutine staining. Based on the histopathological analysis it was confirmed limbal melanocytoma. Postoperative treatmentconsisted...

Treatment of limbal melanocytoma with full excision and a fresh homologous corneoscleral graft in a dog

Background: Limbal melanoma has been diagnosed in dogs and due to progression may cause vision loss and eyeballremoval. Definitive diagnosis is made through histopathological examination. Therapeutic options include full thicknessresection and repair by homologous corneal tissue, synthetic graft material, and enucleation. In this report, we describe acase of limbal melanocitoma in a dog that has been treated successfully with fresh homologous corneoscleral graft.Case: A 5-year-old female Labrador was referred to the Ophthalmology Veterinary Section of the Federal University ofRio Grande do Sul (UFRGS), Porto Alegre, Brazil, with a history of a pigmented mass located on the left eye. Ophthalmicexamination revealed a pigmented mass located at the left temporal limbus with corneal involvement. Surgical excisionfollowed by reconstruction using fresh homologous corneoscleral was recommended. The patient was premedicated withacepromazine (0.05 mg/kg, IM) and meperidine (20 mg/kg, IM). Anaesthesia was induced with propofol (10 mg/kg, IV)and maintained with isoflurane. Atracurium (0.2 mg/kg, IV) was administered to maintain a central eye position. The massand a free margin were removed by full-thickness corneoscleral resection. A corneoscleral graft was harvested from a dogthat had been euthanised for reasons unrelated to this study and sutured with 9-0 polyglactin 910 using a simple interruptedpattern. The mass was immediately fixed in 10% neutral buffered formalin and submitted for histological sectioning androutine staining. Based on the histopathological analysis it was confirmed limbal melanocytoma. Postoperative treatmentconsisted...(AU)

Use of Giemsa staining for the immunohistochemical counterstaining in canine melanomas: an "old and forgotten" method

Melanoma is a neoplasm originating from melanocytes and represents 7% of skin tumors and the most common in oral cavity of dogs. Melanoma may present melanocytic pigment in its cytoplasm in varying quantity and its characterization by immunohistochemistry (IHC) is challenging due to the use of chromogen diaminobenzidine (DAB) which itself produces a brown product what makes difficult to distinguish from melanin pigment in this technique. To demonstrate a reliable technique, the use of the Giemsa counterstaining was performed in the IHC of melanomas with different degrees of pigmentation for different cytoplasmic, membrane and nuclear markers. The modification in the IHC technique by the counterstaining of Giemsa allows observable differences under the microscope between melanic pigment(in a blue-green stain), while the DAB chromogen will be observed in brown. With this technique, the prognostic and predictive interpretation of markers in canine melanomas may be more reliable in definitions of clinical behaviors and inexperimental analyzes.(AU)

Use of Giemsa staining for the immunohistochemical counterstaining in canine melanomas: an "old and forgotten" method

Melanoma is a neoplasm originating from melanocytes and represents 7% of skin tumors and the most common in oral cavity of dogs. Melanoma may present melanocytic pigment in its cytoplasm in varying quantity and its characterization by immunohistochemistry (IHC) is challenging due to the use of chromogen diaminobenzidine (DAB) which itself produces a brown product what makes difficult to distinguish from melanin pigment in this technique. To demonstrate a reliable technique, the use of the Giemsa counterstaining was performed in the IHC of melanomas with different degrees of pigmentation for different cytoplasmic, membrane and nuclear markers. The modification in the IHC technique by the counterstaining of Giemsa allows observable differences under the microscope between melanic pigment(in a blue-green stain), while the DAB chromogen will be observed in brown. With this technique, the prognostic and predictive interpretation of markers in canine melanomas may be more reliable in definitions of clinical behaviors and inexperimental analyzes.

Complicações reprodutivas de melanoma em fêmea equina tordilha da raça Mangalarga Marchador / Reproductive complications of melanoma in female Tordilla Colored Equine

Melanoma is an alteration of melanocytes, cells responsible for skin pigmentation, which allows for unregulated growth, although there is no confirmation about predispositions to this pathology, skin species and white hairs are considered most affected, being especially common in Tordilla colored horses. Although there is a benign form, the case can develop becoming malignant and metastatic in an unpredictable way, and may suffer influence with the advancing age of the horse, with great chances of the tumor becoming aggressive, having high mortality rates, because there is still no effective treatment to combat nodule growth. The aim of the present study was to report a case of melanoma in an equine, female, gray coat, Mangalarga Marchador breed, belonging to Fazenda Escola, Faculty of Nursing Nova Esperança, as well as it possible implications for the reproductive system. In the clinical examination, nodular skin lesions were observed, with firm and painless consistency, located in the regions of the vulva, large lips, oral vestibular of the upper lip and, with the use of vaginoscopy, it was also possible to observe nodules in the vaginal vestibule. Based on these clinical findings, the presumptive diagnosis was melanoma. For a better prognosis, early identification is essential, considering that the later it is done, the greater the possibility of metastasis, reaching subcutaneous regions, cavities and internal organs, compromising physiological functions and being responsible to vaginal obstructions, injuries and decreased fertility, causing great damage to equine reproduction.

Complicações reprodutivas de melanoma em fêmea equina tordilha da raça Mangalarga Marchador / Reproductive complications of melanoma in female Tordilla Colored Equine

Melanoma is an alteration of melanocytes, cells responsible for skin pigmentation, which allows for unregulated growth, although there is no confirmation about predispositions to this pathology, skin species and white hairs are considered most affected, being especially common in Tordilla colored horses. Although there is a benign form, the case can develop becoming malignant and metastatic in an unpredictable way, and may suffer influence with the advancing age of the horse, with great chances of the tumor becoming aggressive, having high mortality rates, because there is still no effective treatment to combat nodule growth. The aim of the present study was to report a case of melanoma in an equine, female, gray coat, Mangalarga Marchador breed, belonging to Fazenda Escola, Faculty of Nursing Nova Esperança, as well as it possible implications for the reproductive system. In the clinical examination, nodular skin lesions were observed, with firm and painless consistency, located in the regions of the vulva, large lips, oral vestibular of the upper lip and, with the use of vaginoscopy, it was also possible to observe nodules in the vaginal vestibule. Based on these clinical findings, the presumptive diagnosis was melanoma. For a better prognosis, early identification is essential, considering that the later it is done, the greater the possibility of metastasis, reaching subcutaneous regions, cavities and internal organs, compromising physiological functions and being responsible to vaginal obstructions, injuries and decreased fertility, causing great damage to equine reproduction.(AU)

Melanin bleaching with potassium permanganate for melanocytic lesions diagnosis in veterinary medicine / Despigmentação de melanócitos com permanganato de potássio para diagnóstico de lesões melanocíticas na medicina veterinária

The aim of this study was to microscopically re-evaluate the melanocytic lesions diagnoses established by the Animal Pathology Laboratory of the Federal University of Uberlândia, in the state of Minas Gerais, Brazil, over a period of eleven years; in addition, to perform a comparative analysis between the conventional histopathological (CH) method and the use of the melanin bleaching (MB) technique with potassium permanganate, sulfuric acid, and oxalic acid solutions. The results of the MB method presented a disagreement in 24.32% of the diagnosis previously by CH, with low agreement (61.0%) and low Kappa coefficient (0.2267). Melanoma was the most frequent lesion, more frequent in elderly and non-breed female dogs. The most frequent melanoma location was in the cutaneous tissue. The presence or absence of a pagetoid spread in cutaneous samples, distribution of melanin, pattern of cell layout, cell morphology, degree of cellular atypia, and the number of mitoses verified after MB were the most important criteria to confirm the diagnosis of malignancy or benignity of the lesions. Evaluating pathologists considered MB to be essential for the majority of diagnoses and an efficient complementary method for the diagnosis of melanocytic lesions, even in cases with a moderate degree of pigmentation.(AU)

Este estudo objetivou reavaliar microscopicamente os diagnósticos de lesões melanocíticas estabelecidos pelo setor de Patologia Animal da Universidade Federal de Uberlândia, em um período de 11 anos, e, com base nesse levantamento, realizar uma análise comparativa entre o método histopatológico convencional (HC) e o método de despigmentação de melanócitos (DM) com permanganato de potássio, ácido sulfúrico e ácido oxálico. A DM revelou discordância em 24,32% dos diagnósticos previamente estabelecidos por HC, apresentando baixa concordância (61,0%) e baixo valor de coeficiente Kappa (0,2267). A alteração mais frequente foi o melanoma, com maior ocorrência em cadelas idosas sem raça definida (SRD). A localização mais frequente dos melanomas foi cutânea. A presença ou ausência de disseminação pagetoide nos casos cutâneos, a forma de distribuição da melanina, o padrão de disposição das células, a morfologia celular, o grau de atipia celular e a quantidade de mitoses verificada após a despigmentação foram critérios de elevada importância para firmar o diagnóstico quanto à malignidade ou benignidade da lesão. A despigmentação foi considerada pelos patologistas avaliadores como essencial para o diagnóstico na maioria dos casos, o que leva a concluir que ela constitui um método complementar eficiente no diagnóstico das lesões melanocíticas, mesmo em casos com grau moderado de pigmentação.(AU)

Melanin bleaching with potassium permanganate for melanocytic lesions diagnosis in veterinary medicine / Despigmentação de melanócitos com permanganato de potássio para diagnóstico de lesões melanocíticas na medicina veterinária

The aim of this study was to microscopically re-evaluate the melanocytic lesions diagnoses established by the Animal Pathology Laboratory of the Federal University of Uberlândia, in the state of Minas Gerais, Brazil, over a period of eleven years; in addition, to perform a comparative analysis between the conventional histopathological (CH) method and the use of the melanin bleaching (MB) technique with potassium permanganate, sulfuric acid, and oxalic acid solutions. The results of the MB method presented a disagreement in 24.32% of the diagnosis previously by CH, with low agreement (61.0%) and low Kappa coefficient (0.2267). Melanoma was the most frequent lesion, more frequent in elderly and non-breed female dogs. The most frequent melanoma location was in the cutaneous tissue. The presence or absence of a pagetoid spread in cutaneous samples, distribution of melanin, pattern of cell layout, cell morphology, degree of cellular atypia, and the number of mitoses verified after MB were the most important criteria to confirm the diagnosis of malignancy or benignity of the lesions. Evaluating pathologists considered MB to be essential for the majority of diagnoses and an efficient complementary method for the diagnosis of melanocytic lesions, even in cases with a moderate degree of pigmentation.(AU)

Este estudo objetivou reavaliar microscopicamente os diagnósticos de lesões melanocíticas estabelecidos pelo setor de Patologia Animal da Universidade Federal de Uberlândia, em um período de 11 anos, e, com base nesse levantamento, realizar uma análise comparativa entre o método histopatológico convencional (HC) e o método de despigmentação de melanócitos (DM) com permanganato de potássio, ácido sulfúrico e ácido oxálico. A DM revelou discordância em 24,32% dos diagnósticos previamente estabelecidos por HC, apresentando baixa concordância (61,0%) e baixo valor de coeficiente Kappa (0,2267). A alteração mais frequente foi o melanoma, com maior ocorrência em cadelas idosas sem raça definida (SRD). A localização mais frequente dos melanomas foi cutânea. A presença ou ausência de disseminação pagetoide nos casos cutâneos, a forma de distribuição da melanina, o padrão de disposição das células, a morfologia celular, o grau de atipia celular e a quantidade de mitoses verificada após a despigmentação foram critérios de elevada importância para firmar o diagnóstico quanto à malignidade ou benignidade da lesão. A despigmentação foi considerada pelos patologistas avaliadores como essencial para o diagnóstico na maioria dos casos, o que leva a concluir que ela constitui um método complementar eficiente no diagnóstico das lesões melanocíticas, mesmo em casos com grau moderado de pigmentação.(AU)

Melanocitoma-acantoma em um cão / Melanocytoma-acanthoma in a dog

Background: Melanocytic neoplasms are skin tumors that often occur in dogs. However, melanocytoma-acanthoma, alsocalled melanoacanthoma, is a benign melanocytic neoplasm rarely reported in this species, which has been described onlythree times in the veterinary literature. Briefly, this tumor is characterized by a single, painless, darkly pigmented and firmcutaneous papule or nodule. Histologically, it is composed of mixed populations of well-differentiated melanocytes andkeratinocytes, unlike traditional melanocytic tumors (melanoma and melanocytoma). These cells are arranged in lobulessurrounded by collagenous stroma. Melanocytes are large epithelioid cells containing varying amounts of melanin. Keratinocytes form anastomosing trabeculae with peripheral palisading, and small cysts containing amorphous or laminatedkeratin. The definitive diagnosis of melanocytoma-acanthoma is based on histopathological findings. This report describesa case of melanocytoma-acanthoma in a dog in Brazil.Case: A 9-year-old female miniature Schnauzer dog was examined at the Veterinary Hospital of the Federal Universityof Santa Maria, where a single, firm, pigmented papule was found in the auricle. The lesion had started 15 days earlier.Hematological tests and serum biochemistry profile were normal. An excisional biopsy of the papule was surgically removed and subjected to histopathological examination. The tissue was fixed in 10% neutral buffered formalin, processedroutinely and embedded in paraffin wax. Sections were stained with hematoxylin and eosin (HE). A histopathologicalexamination revealed a nonencapsulated, well-defined, extensive, densely cellular proliferation located in dermis. Thisproliferation was composed of lobules and nests of well-differentiated stratified squamous epithelium closely associatedwith neoplastic melanocytes, surrounded by thin bundles of fibrous stroma. A diagnosis of...

Melanocitoma-acantoma em um cão / Melanocytoma-acanthoma in a dog

Background: Melanocytic neoplasms are skin tumors that often occur in dogs. However, melanocytoma-acanthoma, alsocalled melanoacanthoma, is a benign melanocytic neoplasm rarely reported in this species, which has been described onlythree times in the veterinary literature. Briefly, this tumor is characterized by a single, painless, darkly pigmented and firmcutaneous papule or nodule. Histologically, it is composed of mixed populations of well-differentiated melanocytes andkeratinocytes, unlike traditional melanocytic tumors (melanoma and melanocytoma). These cells are arranged in lobulessurrounded by collagenous stroma. Melanocytes are large epithelioid cells containing varying amounts of melanin. Keratinocytes form anastomosing trabeculae with peripheral palisading, and small cysts containing amorphous or laminatedkeratin. The definitive diagnosis of melanocytoma-acanthoma is based on histopathological findings. This report describesa case of melanocytoma-acanthoma in a dog in Brazil.Case: A 9-year-old female miniature Schnauzer dog was examined at the Veterinary Hospital of the Federal Universityof Santa Maria, where a single, firm, pigmented papule was found in the auricle. The lesion had started 15 days earlier.Hematological tests and serum biochemistry profile were normal. An excisional biopsy of the papule was surgically removed and subjected to histopathological examination. The tissue was fixed in 10% neutral buffered formalin, processedroutinely and embedded in paraffin wax. Sections were stained with hematoxylin and eosin (HE). A histopathologicalexamination revealed a nonencapsulated, well-defined, extensive, densely cellular proliferation located in dermis. Thisproliferation was composed of lobules and nests of well-differentiated stratified squamous epithelium closely associatedwith neoplastic melanocytes, surrounded by thin bundles of fibrous stroma. A diagnosis of...(AU)

Recurrent laryngeal neuropathy secondary to nerve compression by melanomas - case report / Neuropatia laríngea recorrente secundária à compressão por melanomas - relato de caso

Recurrent laryngeal neuropathy (RLN) etiology can be acquired, iatrogenic or idiopathic. There are no previous reports of RLN caused by recurrent laryngeal nerve compression by melanomas. This report describes a horse presenting severe dyspnea and progressive weight loss. Physical exam demonstrated tachycardia, tachypnea, inspiratory dyspnea at rest, neck extension and mydriasis. Temporary tracheotomy was performed and videoendoscopic examination diagnosed grade IV laryngeal paralysis. The animal came suddenly to death by suppurative bacterial pneumonia. At necropsy, it was possible to observe multiple melanotic epithelioid melanoma nodules compressing the recurrent laryngeal nerve, alongside with lung and parotid metastasis. This finding emphasizes the importance of establishing a differential diagnosis for tumor mass compression in the etiology of RLN, especially melanomas in gray horses, with or without cutaneous manifestations of masses.(AU)

A neuropatia laríngea recorrente (NLR) pode apresentar etiologia adquirida, iatrogênica ou idiopática. Não há relatos prévios da ocorrência da NLR causada pela compressão do nervo laríngeo recorrente por melanomas. Este relato descreve um equino apresentando dispneia grave e perda de peso progressiva. O exame físico demonstrou taquicardia, taquipneia, dispneia inspiratória em repouso, extensão do pescoço e midríase. Foi realizada traqueotomia temporária e exame videoendoscópico, mediante o qual se diagnosticou paralisia laríngea grau IV. O animal veio a óbito por pneumonia bacteriana supurativa. Na necropsia, foi possível observar múltiplos nódulos de melanoma epitelioide amelanótico comprimindo o nervo laríngeo recorrente, juntamente com metástases pulmonares e parotídeas. Este achado enfatiza a importância de estabelecer um diagnóstico diferencial nos casos de NLR, pensando-se na compressão nervosa por massas tumorais, especialmente melanomas em cavalos tordilhos, com ou sem manifestações cutâneas de massas.(AU)