Onychocytic Matricoma: A Clinical, Dermoscopic, and Pathological Analysis of 14 Cases.

ABSTRACT: Onychocytic matricoma (OCM) is a benign neoplasm of the nail matrix. Only 18 cases of this tumor have been reported in the literature to date. We retrospectively analyzed the clinical features of 14 patients with OCM. The most common clinical feature was longitudinal xanthopachyonychia (n = 9), followed by longitudinal leukopachyonychia (=3) and longitudinal pachymelanonychia (n = 2). The most common clinical findings identified following dermoscopy and analysis at high magnification of classical photographs were free-edge thickening of the nail plate without pitting (n = 14), longitudinal ridging (n = 7), round white clods (n = 7), white dots (n = 7), and filiform hemorrhages (n = 7), followed by oval and linear white clods (n = 5), fuzzy lateral border (n = 5), and red-purple blood clods (n = 3). Nail clipping histopathology showed a thickened nail plate with multiple, small, round-to-oval spaces. The tumor expressed immunopositivity for LEF-1. Dermoscopy of the nail plate and nail clipping histology provides useful information with regards to the differential diagnosis with subungual squamous cell carcinoma and nail melanoma. Ex vivo-in vivo correlation facilitates a better dermoscopic assessment of this unique underrecognized disease. However, the differential diagnosis between OCM and onychocytic carcinoma requires biopsy of the tumor. LEF-1 as an onychogenic marker can be used to resolve the differential diagnosis between OCM and subungual longitudinal acanthoma/seborrheic keratosis.

Acantoma de células claras. Estudio clínico de 70 pacientes / Clear Cell Acanthoma: A Series of 70 Cases

Antecedentes y objetivo El acantoma de células claras (ACC) es una lesión poco frecuente caracterizada histológicamente por la presencia de acantosis epidérmica a expensas de queratinocitos de citoplasma claro. Aunque se han descrito muchos casos clínicos de forma individual, se han publicado pocas series de pacientes con ACC. Nuestro objetivo fue analizar las características clínicas del ACC en nuestra población. Material y métodos Estudio retrospectivo de los pacientes con ACC diagnosticados en el Hospital Universitario de Bellvitge en Barcelona, España, entre 1995-2021. Se revisaron las historias clínicas para obtener los siguientes datos: edad, sexo, localización, número de lesiones, diámetro, tiempo de evolución, características clínicas de los tumores, diagnóstico clínico de sospecha y el tratamiento realizado Resultados Setenta pacientes con ACC fueron incluidos en el estudio (30 mujeres y 40 varones, edad media 62 años, DE 13). La mediana del tiempo de evolución fue de dos años, rango intercuartílico (RIQ) 4 y la del diámetro 6 mm, RIQ 5. Una paciente presentó lesiones múltiples. Las lesiones se localizaron en las extremidades inferiores en 57 pacientes (81%), en la cara posterior del tronco en ocho (11%), la cara anterior del tronco en cuatro (5%) y en las extremidades superiores en uno (1%). Se planteó el diagnóstico clínico de ACC en 40% de los pacientes atendidos por dermatólogos. Conclusiones El aspecto clínico característico del ACC es el de una lesión cupuliforme eritematosa con punteado vascular y collarete epidérmico. La proporción de ACC diagnosticados clínicamente ha mejorado respecto a series antiguas, quizás por un mayor conocimiento clínico de la entidad y un mayor uso de la dermatoscopia (AU)

Background and objective Clear cell acanthoma (CCA) is an uncommon lesion histologically characterized by the presence of epidermal acanthosis with keratinocytes containing clear cytoplasm. Although many single cases of CCA have been described, few case series have been published. The aim of this study was to describe the clinical characteristics of CCA in our practice setting. Material and methods Retrospective study of patients diagnosed with CCA at Hospital Universitario de Bellvitge in Barcelona, Spain, between 1995 and 2021. We conducted a chart review to record age, sex, number and location of lesions, diameter, time since onset, clinical characteristics, suspected clinical diagnosis, and treatment. Results Seventy patients (30 women and 40 men) with a mean (SD) age of 62 (13) years were diagnosed with CCA during the study period. Median (interquartile range) time since onset was 2 (4) years and median lesion diameter was 6 (5) mm. One woman had multiple lesions. Lesions were located on the lower extremities in 57 patients (81%), the posterior aspect of the trunk in 8 (11%), the anterior aspect of the trunk in 4 (5%), and the upper extremities in 1 (1%). CCA was clinically suspected in 40% of patients seen by dermatologists. Conclusions CCA presents as an erythematous, dome-shaped lesion with pinpoint vessels and an epidermal collarette. The accuracy of clinical diagnosis has improved relative to earlier series, possibly due to a better clinical understanding of this lesion and a greater use of dermoscopy (AU)

[Translated article] Clear Cell Acanthoma: A Series of 70 Cases / Acantoma de células claras. Estudio clínico de 70 pacientes

Background and objective Clear cell acanthoma (CCA) is an uncommon lesion histologically characterized by the presence of epidermal acanthosis with keratinocytes containing clear cytoplasm. Although many single cases of CCA have been described, few case series have been published. The aim of this study was to describe the clinical characteristics of CCA in our practice setting. Material and methods Retrospective study of patients diagnosed with CCA at Hospital Universitario de Bellvitge in Barcelona, Spain, between 1995 and 2021. We conducted a chart review to record age, sex, number and location of lesions, diameter, time since onset, clinical characteristics, suspected clinical diagnosis, and treatment. Results Seventy patients (30 women and 40 men) with a mean (SD) age of 62 (13) years were diagnosed with CCA during the study period. Median (interquartile range) time since onset was 2 (4) years and median lesion diameter was 6 (5)mm. One woman had multiple lesions. Lesions were located on the lower extremities in 57 patients (81%), the posterior aspect of the trunk in 8 (11%), the anterior aspect of the trunk in 4 (5%), and the upper extremities in 1 (1%). CCA was clinically suspected in 40% of patients seen by dermatologists. Conclusions CCA presents as an erythematous, dome-shaped lesion with pinpoint vessels and an epidermal collarette. The accuracy of clinical diagnosis has improved relative to earlier series, possibly due to a better clinical understanding of this lesion and a greater use of dermoscopy (AU)

Antecedentes y objetivo El acantoma de células claras (ACC) es una lesión poco frecuente caracterizada histológicamente por la presencia de acantosis epidérmica a expensas de queratinocitos de citoplasma claro. Aunque se han descrito muchos casos clínicos de forma individual, se han publicado pocas series de pacientes con ACC. Nuestro objetivo fue analizar las características clínicas del ACC en nuestra población. Material y métodos Estudio retrospectivo de los pacientes con ACC diagnosticados en el Hospital Universitario de Bellvitge en Barcelona, España, entre 1995-2021. Se revisaron las historias clínicas para obtener los siguientes datos: edad, sexo, localización, número de lesiones, diámetro, tiempo de evolución, características clínicas de los tumores, diagnóstico clínico de sospecha y tratamiento realizado. Resultados Setenta pacientes con ACC fueron incluidos en el estudio (30 mujeres y 40 varones, edad media: 62 años, DE: 13). La mediana del tiempo de evolución fue de 2 años, rango intercuartílico (RIQ): 4 y la del diámetro 6mm, RIQ: 5. Una paciente presentó lesiones múltiples. Las lesiones se localizaron en las extremidades inferiores en 57 pacientes (81%), en la cara posterior del tronco en 8 pacientes (11%), la cara anterior del tronco en 4 pacientes (5%) y en las extremidades superiores en un paciente (1%). Se planteó el diagnóstico clínico de ACC en el 40% de los pacientes atendidos por dermatólogos. Conclusiones El aspecto clínico característico del ACC es el de una lesión cupuliforme eritematosa con punteado vascular y collarete epidérmico. La proporción de ACC diagnosticados clínicamente ha mejorado respecto a series antiguas, quizás por un mayor conocimiento clínico de la entidad y un mayor uso de la dermatoscopia (AU)

Clear Cell Acanthoma: A Series of 70 Cases. / Acantoma de células claras. Estudio clínico de 70 pacientes.

BACKGROUND AND OBJECTIVE: Clear cell acanthoma (CCA) is an uncommon lesion histologically characterized by the presence of epidermal acanthosis with keratinocytes containing clear cytoplasm. Although many single cases of CCA have been described, few case series have been published. The aim of this study was to describe the clinical characteristics of CCA in our practice setting. MATERIAL AND METHODS: Retrospective study of patients diagnosed with CCA at Hospital Universitario de Bellvitge in Barcelona, Spain, between 1995 and 2021. We conducted a chart review to record age, sex, number and location of lesions, diameter, time since onset, clinical characteristics, suspected clinical diagnosis, and treatment. RESULTS: Seventy patients (30 women and 40 men) with a mean (SD) age of 62 (13) years were diagnosed with CCA during the study period. Median (interquartile range) time since onset was 2 (4) years and median lesion diameter was 6 (5) mm. One woman had multiple lesions. Lesions were located on the lower extremities in 57 patients (81%), the posterior aspect of the trunk in 8 (11%), the anterior aspect of the trunk in 4 (5%), and the upper extremities in 1 (1%). CCA was clinically suspected in 40% of patients seen by dermatologists. CONCLUSIONS: CCA presents as an erythematous, dome-shaped lesion with pinpoint vessels and an epidermal collarette. The accuracy of clinical diagnosis has improved relative to earlier series, possibly due to a better clinical understanding of this lesion and a greater use of dermoscopy.

Diagnostic utility of SOX10 immunostaining in benign lichenoid keratosis: A study of 21 cases.

BACKGROUND: Benign lichenoid keratosis (BLK) is a cutaneous lesion that can clinically mimic malignancy and may represent regression of a pre-existing lesion. BLK may show epidermal pseudo-nests prompting evaluation for a melanocytic lesion. False positivity of MART-1/Melan-A immunostaining in pseudonests has been showed; however, the value of SRY-related HMG-box 10 (SOX10) staining in BLK with features suspicious for a melanocytic proliferation has not been previously reported. METHODS: Twenty-one cases of BLK from 2015 to 2020 were identified. Slides were reviewed and SOX10 immunohistochemistry was performed on each case. Subsequently, Melan-A immunohistochemical staining was performed on all cases. RESULTS: In 10 cases (47.6%), unexpected SOX10 staining was seen in rare to numerous small, single cells in the epidermis above the basal cell layer. No malignancy was identified. Of the 10 cases, 8 (80%) showed suprabasal SOX10 staining did not show similar suprabasal Melan-A staining; 2 (20%) cases showed scattered suprabasal cells positive for Melan-A. CONCLUSION: SOX10 immunostaining in BLK can highlight scattered cells in the epidermis (not easily noticeable on routine stain). Performing SOX10 immunostain alone on BLK can prompt a misdiagnosis of a melanocytic lesion and should be done with caution.

A conscious minimally invasive approach to remove follicular cysts and infundibular keratinizing acanthomas in five dogs.

Follicular cysts and infundibular keratinizing acanthomas are common benign cutaneous lesions in dogs. Current treatment options include surgical excision under general anaesthesia, cryotherapy, carbon dioxide laser and retinoids, each with potential disadvantages. We describe a conscious, minimally invasive, surgical excision procedure with high success rate and no complications in five dogs.

Les kystes folliculaires et les acanthomes kératinisant infundibulaires sont des lésions cutanées bénignes fréquentes chez le chien. Les options de traitement actuelles comprennent l'exérèse chirurgicale sous anesthésie générale, la cryothérapie, le laser au dioxyde de carbone et les rétinoïdes, chacun présentant des inconvénients potentiels. Nous décrivons une procédure d'exérèse chirurgicale consciente, peu invasive, avec un taux de réussite élevé et aucune complication chez cinq chiens.

Los quistes foliculares y los acantomas queratinizantes infundibulares son lesiones cutáneas benignas comunes en perros. Las opciones de tratamiento actuales incluyen la escisión quirúrgica bajo anestesia general, crioterapia, láser de dióxido de carbono y retinoides, cada uno con posibles desventajas. Describimos un procedimiento de escisión quirúrgica consciente, mínimamente invasivo, con una alta tasa de éxito y sin complicaciones en cinco perros.

Cistos foliculares e acantomas infundibulares queratinizantes são lesões cutâneas benignas em cães. As opções terapêuticas existentes atualmente são excisão cirúrgica sob anestesia geral, crioterapia, laser de dióxido de carbono e retinoides, cada um com desvantagens potenciais. Nós descrevemos aqui um procedimento de excisão cirúrgica minimamente invasivo, consciente, com um grande potencial de sucesso e sem complicações em cinco cães.

Follicular Porokeratoma: Report of a New Variant of Porokeratoma (Porokeratotic Acanthoma) and Literature Review.

ABSTRACT: Porokeratoma is a rare type of epidermal acanthoma, of which 22 cases have been published in the literature. It is characterized by the presence of multiple cornoid lamellae embedded within a single verrucous or keratotic nodule. Despite this histologic feature being shared with porokeratosis, the etiopathogenesis of porokeratoma and its relationship with porokeratosis remain unclear. We report a new case of porokeratoma involving hair follicles, a finding that has been reported in only one of the previously published cases. Analogous to follicular porokeratosis, a form of porokeratosis involving hair follicles, we have termed this lesion "follicular porokeratoma." A review of all 23 published cases (including the present case) is also provided.

Update from the 5th Edition of the World Health Organization Classification of Head and Neck Tumors: Tumours of the Oral Cavity and Mobile Tongue.

The fifth chapter of the upcoming fifth edition of the 2022 World Health Organization Classification of Tumours of the Head and Neck titled Tumours of the oral cavity and mobile tongue, has had some modifications from the 2017 fourth edition. A new section "Non-neoplastic Lesions", introduces two new entries: necrotizing sialometaplasia and melanoacanthoma. The combined Oral potentially malignant disorders and Oral epithelial dysplasia section in the 2015 WHO has now been separated and submucous fibrosis and HPV-associated dysplasia are also discussed in separate sections. Carcinoma cuniculatum and verrucous carcinoma are described in dedicated sections, reflecting that the oral cavity is the most common location in the head and neck for both these entities which have distinct clinical and histologic features from conventional squamous cell carcinoma. This review summarizes the changes in Chapter 5 with special reference to new additions, deletions, and sections that reflect current clinical, histological, and molecular advances.

Multiple eruptive clear cell acanthomas successfully treated with CO2 laser ablation.

Clear cell acanthoma (CCA) is a rare, benign epidermal lesion of clear glycogen-containing keratinocytes. The exact etiology is unknown. Although CCA usually appear as solitary lesions, cases of multiple CCAs have also been described. The rare eruptive CCA variant describes cases with more than 30 lesions.Current therapeutic evidence for the management of multiple CCAs is limited. CO2 laser remains the most widely used laser in clinical practice. However, literature describing its effectiveness on CCA is sparse, and previous reports have described its use for a maximum of three lesions. To our knowledge, this is the first report of successful CO2 laser treatment of the multiple eruptive CCA variant with an excellent cosmetic outcome.Our case adds to the evidence that CO2 laser is an effective treatment for this condition. Particularly in those patients with refractory or multiple eruptive CCAs, or for those who may not tolerate repeated courses of cryotherapy, or who are concerned about scarring and cosmetic outcome.

Case Report of Conjunctival Melanoacanthoma.

PURPOSE: The purpose of this study was to describe a case of conjunctival melanoacanthoma, an exceedingly rare condition that has yet to be fully described in the literature. METHODS: Melanoacanthomas are most commonly seen on the skin or oral mucosa and are believed to result from local irritation or trauma. A 34-year-old Hispanic man presented with a painless, solitary, pigmented conjunctival lesion, in addition to bilateral pterygia suggesting chronic solar damage. The lesion was excised and sent for analysis. RESULTS: Histopathologic analysis of tissue samples demonstrated melanocyte proliferation and epithelial dysplasia, yielding a final pathologic diagnosis of conjunctival melanoacanthoma with dysplastic and acantholytic-type features. The patient is being closely followed and has not had recurrence of the lesion. CONCLUSIONS: Only 1 prior case of conjunctival melanoacanthoma has been documented. As such, there is no standard of care regarding appropriate management.

Comparative Immunohistochemical Study of Hidroacanthoma Simplex and Clonal Seborrheic Keratosis With GATA3 and p63.

ABSTRACT: Histopathologically both hidroacanthoma simplex (HS) and clonal seborrheic keratosis (CSK) are characterized by intraepidermal nests of tumor cells. Although they show subtle microscopic differences, they can be difficult to accurately differentiate. Previous immunohistochemical studies have been inconclusive. We conducted an immunohistochemical study with GATA3 and p63 on cases of HS and CSK tentatively identified by their microscopic appearances and cases of eccrine poroma and seborrheic keratosis as their respective controls. The clinical, histopathological, and dermoscopic findings of these cases were also reviewed. All cases of HS and poroma were negative for GATA3, whereas all cases of CSK and seborrheic keratosis were positive for GATA3. HS, CSK, and their controls were all positive for p63. Microscopic, clinical, and dermoscopic differences were also found between HS and CSK. Our study demonstrated that GATA3 is useful for differentiating HS from CSK. Our initial microscopic observations also proved to be reliable, but immunostaining with GATA3 is helpful for confirming the diagnosis or establishing the diagnosis of uncertain cases. Awareness of the clinical and dermoscopic features of these 2 entities could also avoid misdiagnosis based solely on pathological observation.

Clear Cell Proliferations of the Skin: A Histopathologic Review.

ABSTRACT: Cutaneous clear cell proliferations encompass a heterogenous group of several primary cutaneous neoplasms and metastatic tumors with different histogenesis. Many of these clear cell proliferations may seem strikingly similar under the microscope resulting in challenging diagnosis. In many of these clear cell lesions, the reason for the clear or pale appearance of proliferating cells is unknown, whereas in other ones, this clear cell appearance is due to intracytoplasmic accumulation of glycogen, mucin, or lipid. Artifacts of tissue processing and degenerative phenomenon may also be responsible for the clear cell appearance of proliferating cells. Awareness of the histopathologic findings as well as histochemical and immunohistochemical techniques are crucial to the accurate diagnosis. This review details the histopathologic features of clear cell cutaneous proliferations, classifying them according their type of differentiation and paying special attention to the histopathologic differential diagnosis among them.

Hypergranulotic Dyskeratotic Acanthoma: Another Histologically Distinctive Acanthoma.

ABSTRACT: Various acanthomas have been named based on their distinctive histopathologic patterns. Hypergranulotic dyskeratotic acanthoma represents another acanthoma with a distinctive histopathologic pattern that has been rarely reported. In this article, clinical and histological features of hypergranulotic dyskeratotic acanthoma are delineated. A retrospective analysis was performed of cases with diagnosis or suggested diagnosis of hypergranulotic dyskeratotic acanthoma between 2012 and 2017 from 2 dermatopathology laboratories. Forty-eight potentials were identified, of which 18 cases met the inclusion histologic criteria. Most cases came from women (78%) with a mean age of 53 years, and the thigh was the most common site involved. All cases had the following histopathological findings: (1) verrucous or digitated epidermal hyperplasia, (2) hyperkeratosis dominated by basketweave or compact orthokeratosis, (3) hypergranulosis involving the breadth of the lesion, and (4) presence of enlarged, often indistinctly bordered, keratinocytes with cytoplasm characterized by a blue-gray granular peripheral zone sometimes showing outstretched desmosomes and central perinuclear eosinophilic zones, a combination of findings representing slowly evolving dyskeratosis. Retrospective nature and a small sample size are the major limitations of the study. In sum, hypergranulotic dyskeratotic acanthoma can be easily distinguished from other acanthomas based on their repeatable histopathological findings.

Hyaline Inclusion Acanthoma.

ABSTRACT: Eosinophilic hyaline inclusions (EHIs) or globules have been reported in various cutaneous tumors including vascular lesions, myoepithelial neoplasms, and basal cell carcinoma. In basal cell carcinoma, the presence of intracytoplasmic inclusions is reportedly associated with myoepithelial differentiation. In this regard, EHI has not been conclusively documented in a cutaneous lesion of genuine squamous cell lineage without aberrant differentiation. In the current case, a biopsy from the right thigh of a 71-year-old male patient demonstrated a relatively well-demarcated intraepidermal squamous lesion featured an admixture of predominantly enlarged keratinocytes harboring distinct eccentric intracytoplasmic EHI and a smaller population of keratinocytes displaying pale cytoplasm. Cytologic atypia, mitotic activity, and inflammatory cells were not identified. The intracytoplasmic EHI stained red with Masson's trichrome and were negative with periodic-acid Schiff with and without diastase. Immunologically, the lesion was strongly and diffusely positive for various cytokeratins but negative for ubiquitin and myoepithelial markers. Only cytokeratin AE1 revealed a differential staining pattern as the suprabasal lesional cells displayed significantly stronger immunoreactivity in comparison with the adjacent normal keratinocytes. Polymerase chain reaction for low-risk and high-risk human papillomavirus was negative. Molecular studies did not reveal any mutations commonly encountered in seborrheic or lichenoid keratoses. As an analogous lesion has not previously reported in the literature, the term hyaline inclusion acanthoma is proposed for this peculiar lesion.

Epidermolytic acanthoma in a young woman: a case letter.

Epidermolytic acanthoma (EA) is a rare benign tumor that is characterized by epidermolytic hyperkeratosis on histopathology. It usually presents in adulthood as an asymptomatic tumor <1 cm in diameter with a verrucous surface. We report a very uncommon case of epidermolytic acanthoma. A 21-year-old woman came to our hospital with a pale black papule on the left lower eyelid near the Inner canthus for 2 months. Two months ago the patient noted a pale brown spot on the inside of the left lower eyelid, which gradually enlarged, forming a papule with a deepened color. There were no associated symptoms, such as itching or pain. There were no local injuries, scratches, or other incidents before the crash occurred. The patient was always healthy, with no history of chronic disease or other skin diseases, and no similar cases existed in the family. We diagnosed it as EA.

Differences in dermoscopic findings between early and mature clear cell acanthoma.

Clear cell acanthoma (CCA) is a rare benign epidermal tumor that is difficult to diagnose by visual inspection. Conversely, its diagnosis by dermoscopy is relatively easy owing to the characteristic serpiginous arrangement of coiled vessels, sometimes described as the "string-of-pearls" formation. However, in few published reports, the dermoscopic diagnosis of mature CCA has been reported. Here, we report the histopathological and detailed dermoscopic findings of two CCA cases. Between these, one case was of early (~6 months) CCA exhibiting the characteristic vascular string-of-pearls formation, whereas the other was of a more mature (~10 years) CCA; although the latter case showed combined thick and thin white intersecting lines with large coiled vessels and/or red clods, it had the string-of-pearls formation. Thus, regardless of CCA maturity, the string-of-pearls formation was present. We propose that the combination of combined thick and thin white intersecting lines along with the vascular string-of-pearls formation reflecting large coiled vessels and/or red clods on dermoscopy is a diagnostic clue to mature CCA.