Tarsal villonodular tenosynovitis (giant cell tumor of tendon sheath) in a dog / Tenossinovite vilonodular pigmentada (tumor de células gigantes da bainha tendínea) tarsal em um cão

A 12-year-old female mixed-breed dog presented with lameness, pain, and an enlarged, non-ulcerated, nodular mass in the region proximal to the tarsal joint of the right pelvic limb. Surgical excision was performed, revealing a 6.5 cm mass adherent to the deep flexor tendon and adjacent tissues. The cut section had cysts filled with blackened clotted material, which exuded reddish serous fluid. Microscopically, the cysts were filled with red blood cells and were either denuded or covered by synoviocytes. In addition, the mass was characterized by marked fibrovascular connective tissue associated with siderophages and multinucleated giant cells. These findings were consistent with those of pigmented villonodular tenosynovitis, a rare condition affecting several animal species and humans.

Uma cadela de 12 anos, sem raça definida, apresentou claudicação, algia e aumento de volume não ulcerado, de aspecto nodular, na região proximal à articulação do tarso do membro pélvico direito. A excisão cirúrgica foi optada e revelou uma massa de 6,5 cm de diâmetro, aderida ao tendão flexor profundo e aos tecidos adjacentes. Ao corte, exsudava líquido seroso avermelhado e cistos preenchidos por material coagulado enegrecido foram observados. Microscopicamente, a massa apresentava formações císticas frequentemente preenchidas por hemácias, que encontravam-se ora revestidas por sinoviócitos, ora desnudas. Havia ainda acentuada quantidade de tecido fibrovascular associado a siderófagos e células gigantes multinucleadas. Esses achados foram consistentes com tenossinovite vilonodular pigmentada, uma rara condição que afeta diversas espécies de animais e humanos.

Tarsal villonodular tenosynovitis (giant cell tumor of tendon sheath) in a dog / Tenossinovite vilonodular pigmentada (tumor de células gigantes da bainha tendínea) tarsal em um cão

ABSTRACT: A 12-year-old female mixed-breed dog presented with lameness, pain, and an enlarged, non-ulcerated, nodular mass in the region proximal to the tarsal joint of the right pelvic limb. Surgical excision was performed, revealing a 6.5 cm mass adherent to the deep flexor tendon and adjacent tissues. The cut section had cysts filled with blackened clotted material, which exuded reddish serous fluid. Microscopically, the cysts were filled with red blood cells and were either denuded or covered by synoviocytes. In addition, the mass was characterized by marked fibrovascular connective tissue associated with siderophages and multinucleated giant cells. These findings were consistent with those of pigmented villonodular tenosynovitis, a rare condition affecting several animal species and humans.

RESUMO: Uma cadela de 12 anos, sem raça definida, apresentou claudicação, algia e aumento de volume não ulcerado, de aspecto nodular, na região proximal à articulação do tarso do membro pélvico direito. A excisão cirúrgica foi optada e revelou uma massa de 6,5 cm de diâmetro, aderida ao tendão flexor profundo e aos tecidos adjacentes. Ao corte, exsudava líquido seroso avermelhado e cistos preenchidos por material coagulado enegrecido foram observados. Microscopicamente, a massa apresentava formações císticas frequentemente preenchidas por hemácias, que encontravam-se ora revestidas por sinoviócitos, ora desnudas. Havia ainda acentuada quantidade de tecido fibrovascular associado a siderófagos e células gigantes multinucleadas. Esses achados foram consistentes com tenossinovite vilonodular pigmentada, uma rara condição que afeta diversas espécies de animais e humanos.

Tarsal villonodular tenosynovitis (giant cell tumor of tendon sheath) in a dog / Tenossinovite vilonodular pigmentada (tumor de células gigantes da bainha tendínea) tarsal em um cão

A 12-year-old female mixed-breed dog presented with lameness, pain, and an enlarged, non-ulcerated, nodular mass in the region proximal to the tarsal joint of the right pelvic limb. Surgical excision was performed, revealing a 6.5 cm mass adherent to the deep flexor tendon and adjacent tissues. The cut section had cysts filled with blackened clotted material, which exuded reddish serous fluid. Microscopically, the cysts were filled with red blood cells and were either denuded or covered by synoviocytes. In addition, the mass was characterized by marked fibrovascular connective tissue associated with siderophages and multinucleated giant cells. These findings were consistent with those of pigmented villonodular tenosynovitis, a rare condition affecting several animal species and humans.(AU)

Uma cadela de 12 anos, sem raça definida, apresentou claudicação, algia e aumento de volume não ulcerado, de aspecto nodular, na região proximal à articulação do tarso do membro pélvico direito. A excisão cirúrgica foi optada e revelou uma massa de 6,5 cm de diâmetro, aderida ao tendão flexor profundo e aos tecidos adjacentes. Ao corte, exsudava líquido seroso avermelhado e cistos preenchidos por material coagulado enegrecido foram observados. Microscopicamente, a massa apresentava formações císticas frequentemente preenchidas por hemácias, que encontravam-se ora revestidas por sinoviócitos, ora desnudas. Havia ainda acentuada quantidade de tecido fibrovascular associado a siderófagos e células gigantes multinucleadas. Esses achados foram consistentes com tenossinovite vilonodular pigmentada, uma rara condição que afeta diversas espécies de animais e humanos.(AU)

Cutaneous hemangiosarcoma in a buff-throated saltator (Saltator maximus) with lung metastasis

Hemangiosarcomas are malignant neoplasms arising from endothelial cells of blood vessels. A three-year-old male buff-throated saltator (Saltator maximus) was referred to the Veterinary Hospital of the Universidade Federal da Paraíba (HV-UFPB) due to a recurrent tan nodular mass in the pericloacal region. Surgery for excision of the mass was attempted but the bird died during the surgical procedure. The nodule and the carcass were sent for gross and histological evaluation. Histopathology revealed large blood-filled vascular spaces lined by pleomorphic endothelial cells, which were also observed in the lungs. These findings suggested the diagnosis of hemangiosarcoma that was confirmed by immunohistochemistry against factor VIII-related antigen.

Cutaneous hemangiosarcoma in a buff-throated saltator (Saltator maximus) with lung metastasis

Hemangiosarcomas are malignant neoplasms arising from endothelial cells of blood vessels. A three-year-old male buff-throated saltator (Saltator maximus) was referred to the Veterinary Hospital of the Universidade Federal da Paraíba (HV-UFPB) due to a recurrent tan nodular mass in the pericloacal region. Surgery for excision of the mass was attempted but the bird died during the surgical procedure. The nodule and the carcass were sent for gross and histological evaluation. Histopathology revealed large blood-filled vascular spaces lined by pleomorphic endothelial cells, which were also observed in the lungs. These findings suggested the diagnosis of hemangiosarcoma that was confirmed by immunohistochemistry against factor VIII-related antigen.(AU)

Identificação e distribuição de lesões cardíacas em bovinos intoxicados por Amorimia exotropica / Identification and distribution of cardiac lesions in cattle poisoned by Amorimia exotropica

Amorimia exotropica é um arbusto escandente que pertence à família Malpighiacea, cujo princípio tóxico é o monofluoracetato de sódio e possui ação cardiotóxica em bovinos. Ela é a única representante, na região Sul do país, do grupo de plantas que causam morte súbita associada ao exercício. Este trabalho identificou e mapeou as lesões cardíacas observadas em bovinos intoxicados naturalmente por A. exotropica. Selecionaram-se nove corações bovinos, provenientes de um surto de intoxicação natural pela planta em uma propriedade de gado de corte do Rio Grande do Sul e procedeu-se o mapeamento de oito regiões topográficas distintas (ápice, ventrículos direito e esquerdo, septo interventricular, músculos papilares direito e esquerdo e átrios direito e esquerdo). À avaliação macroscópica quatro bovinos apresentaram lesão focal e bem delimitada no músculo papilar esquerdo. Estas áreas na histologia correspondiam à necrose de coagulação em diferentes estágios de evolução, similares a infartos. Todos os bovinos apresentavam necrose de cardiomiócitos, caracterizadas por retração e hipereosinofilia citoplasmática e fragmentação celular em todas as áreas amostradas. A severidade da injúria celular foi avaliada pela imuno-histoquímica anti-troponina C, a qual demonstrou acentuada perda e/ou diminuição de marcação citoplasmática em células necróticas. O músculo papilar esquerdo foi a região mais acometida nos casos de intoxicação por Amorimia exotropica.(AU)

Amorimia exotropica is a shrub of the Malpighiacea family that contains sodium monofluoroacetate as the toxic principle, which has a cardiotoxic action in cattle. In Southern Brazil it is the only species of the group of plants that causes "sudden death during exercise". This study has identified and mapped cardiac lesions observed in cattle naturally poisoned by A. exotropica. An outbreak of poisoning by the plant occurred in a beef cattle herd in Rio Grande do Sul, where nine bovine hearts were selected for examination and mapping of eight distinct topographical regions (apex, right and left ventricles, interventricular septum, right and left papillary muscles , right and left atrium). At gross examination, four cattle showed focal and well-defined lesions in the left papillary muscle. This corresponds to areas of coagulation necrosis in different stages of evolution on histology, similar to infarcts. All hearts showed cardiomyocytes necrosis, characterized by shrinkage and hypereosinophilic cytoplasm and cellular fragmentation in all sampled areas. The severity of cellular injury was evaluated by immunohistochemistry anti-troponin C, which showed marked decrease of cytoplasm staining in necrotic cells. The left papillary muscle was the most affected region in cases of poisoning by A. exotropica.(AU)

Perfuração de úlcera gastroduodenal em felino – relato de caso / Gastroduodenal perfuration ulcer in a cat – case report

As úlceras gastroduodenais são incomuns em gatos e suas causas ainda não estão bem esclarecidas (LIPTAK et al., 2002; CARIOU et al., 2010). Contudo, elas podem estar associadas a neoplasias, anti-inflamatórios não esteroidais, estresse, hiperacidez gástrica, hipovolemia, falência renal, endoparasitas e intoxicações (LIPTAK et al., 2002; NELSON e COUTO, 2006; CARIOU et al., 2010). O presente estudo tem como objetivo relatar um caso de úlcera gastroduodenal em felino.

Perfuração de úlcera gastroduodenal em felino relato de caso / Gastroduodenal perfuration ulcer in a cat case report

As úlceras gastroduodenais são incomuns em gatos e suas causas ainda não estão bem esclarecidas (LIPTAK et al., 2002; CARIOU et al., 2010). Contudo, elas podem estar associadas a neoplasias, anti-inflamatórios não esteroidais, estresse, hiperacidez gástrica, hipovolemia, falência renal, endoparasitas e intoxicações (LIPTAK et al., 2002; NELSON e COUTO, 2006; CARIOU et al., 2010). O presente estudo tem como objetivo relatar um caso de úlcera gastroduodenal em felino.(AU)

Diagnóstico post mortem da síndrome dilatação vólvulo gástrica em cães / Post-mortem Diagnosis of Gastric Dilatation Volvulus Syndrome in Dogs

Background: Gastric dilatation volvulus syndrome (GDV) is an acute and severe disease affecting specially dogs of big breeds. It is a severe illness, which may have a high risk of death if not treated quickly. GDV consists in stomach acute dilatation and rotation, resulting in decrease of gastric and splenic infusion, in addition to the obstruction of abdominal venous return. The aim of this research was to analyze clinical pathological findings of dogs with GDV diagnosis in which necropsy was performed. Materials, Methods & Results: The necropsy records were reviewed from January 2001 to December 2011 to identify these cases. In the period, 4877 autopsies were performed by the Setor de Patologia Veterinária from Universidade Federal do Rio Grande do Sul (UFRGS), being 55 cases (1.15%) of GDV. Four main breeds were identified: Fila Brasileiro (43.6%), Great Dane (12.7%), German Shepherd (10.9%) and Boxer (5.4%). Clinical signs such as bloating, lethargy and dyspnoea were reported. At necropsy, the findings that consisted with gastric alterations were stomach distention due to accumulation of gas, dark red mucosa, and rotations of 90° to 360° especially clockwise. Splenomegaly was observed in 96.36% of dogs and V-shaped spleen in 60%. There was compressive atelectasis in 38.18% of autopsies. The main histological findings in the stomach were characterized by congestion, hemorrhage and necrosis of the mucosa. In the spleen, congestion and necrosis of lymphoid follicles were found. Discussion: When GDV's casuistic is analyzed, our results were similar to other studies, with 0.7% and 2.5%. What is concerned about the breed and age of the animals affected is the high number of GDV in breeds such as Great Dane and German Shepherd. However, we also found high numbers of Fila Brasileiro, a Brazilian breed, that hasn't been mentioned in other studies about this illness before. Similar clinical signs were described by other authors, between them, vomit, a previous sign of acute GDV, which is expected as while there is a gastric rotation, gastric-oesophageal obstruction happens. However, vomit is described as GVD predisposing factor associated to aerophagia, and should be considered a previous sign to the dislocation. The observation of gastric clockwise rotation in most cases is described as the most frequent. Gastric pathologic findings are characteristics of a circulatory compromising due to the rotation, leading to ischemic areas and necrosis. Splenomegaly and the identification of the V-shaped spleen were commonly observed, because when GDV happens, the spleen follows the gastric displacement by the presence of the gastrosplenic ligament. These findings cause splenic congestion by obstruction of venous return, which may lead it to twist too. It is concluded that the GDV was responsible for a low number of necropsies, reaching large and giant breeds. The identification of a large number of Fila breed dogs suggests that this breed is predisposed to the GDV. The gastric lesions indicated circulatory injury by vascular obstruction due to the rotation. Lung compressive atelectasis occurs secondary to gastric distention, also, compression of the caudal vena cava and of the portal vein can occur, decreased venous return, less displacement of blood from the right ventricle to be oxygenated by the lungs leading to breathing recrudescence.

Novos aspectos sobre a intoxicação por Trema micrantha (Cannabaceae) em equídeos / New aspects of Trema micrantha (Cannabaceae) poisoning in equids

Trema micrantha é uma planta arbórea distribuída amplamente no Brasil. Descrevem-se nesse trabalho novos aspectos epidemiológicos e patológicos relacionados com a intoxicação por essa planta em equídeos. Dois equinos adultos da raça Crioula e dois asininos, de localidades distintas, foram intoxicados naturalmente por Trema micrantha, após consumirem grande quantidade da planta que ficou disponível a eles após uma poda. Além disso, um cavalo adulto, de outra propriedade, que estava passando por restrição alimentar, se intoxicou após consumir as partes baixas de um grande número de árvores jovens de T. micrantha. Clinicamente, em todos os equídeos a doença se caracterizou por alterações neurológicas, que apareceram três a quatro dias após o consumo da planta, com curso clínico de dois a quatro dias (abreviadas por eutanásia). Os principais achados de necropsia foram observados no fígado, que estavam levemente aumentados e com padrão lobular evidente e no sistema nervoso central (SNC), com múltiplas áreas amareladas, focos de malacia e hemorragia, principalmente, no tronco cerebral e cerebelo. Histologicamente, havia necrose hepática aguda, edema acentuado no SNC com degeneração fibrinoide da parede de vasos associada a hemorragia e trombose e, frequentemente, com infiltrado de neutrófilos. Outras alterações observadas nos encéfalos foram: grande quantidade de astrócitos de Alzheimer tipo II na substância cinzenta, acúmulos de células Gitter e degeneração Walleriana próxima a focos de lesões vasculares. (AU)

Trema micrantha is a tree widely distributed in Brazil. This paper describes new epidemiological and pathological aspects of this plant poisoning in equids. Two adult horses, Criollo breed and two donkeys from different locations were naturally poisoned by Trema micrantha after consuming large amounts of the plant which was available to them due to pruning. Also an adult horse from another ranch, which was undergoing dietary restriction, was poisoned after consuming the lower parts of a large number of young T. micrantha trees. Clinically, in all cases, the disease was characterized by neurological symptoms that started 3 to 4 days after consumption of the plant, with a clinical course that varied 2 to 4 days (abbreviated by euthanasia). The main gross findings were in the liver, which had slightly increased lobular pattern evident, and in the central nervous system (CNS) with multiple yellowish areas, foci of malacia and hemorrhage, especially in the brainstem and cerebellum. Histologically, there was acute liver necrosis with marked edema of the CNS with fibrinoid vessel wall degeneration, hemorrhage and thrombosis as well as neutrophil infiltration. Other changes in the brain were Alzheimer type II astrocytes in the gray matter, accumulation of Gitter cells and Wallerian degeneration near to vascular lesion foci. (AU)

Hepatopatia crônica associada ao acúmulo de cobre em um cão da raça American Pitbull Terrier / Chronic Liver Disease Associated to Copper Accumulation in an American Pitbull Terrier

Background: The liver plays a variety of essential biochemical functions such as the metabolism of carbohydrates, proteins, lipids and vitamins, the maintenance of blood glucose and bile acids synthesis. Hepatic insufficiency occurs when 70 to 80% of the functional liver mass is committed the liver is unable to metabolize substances on the circulation. In some cases, chronic liver disease may be associated with copper accumulation, which may occur by increased dietary intake, faults in hepatic copper metabolism or liver diseases that cause colestase. The purpose of this paper is to report a case of chronic liver disease associated with copper accumulation in a 8-month-old American Pit Bull Terrier. Case: An American Pitbull Terrier was referred to the Veterinary Teaching Hospital of the Federal University of Rio Grande do Sul with a history of abdominal distension, decreased appetite, vomiting, diarrhea, weight loss and exhaustion. On physical examination the animal presented ascites and dehydration and laboratory tests were suggestive of active liver disease. Supportive care was provided. The patient was prescribed ranitidine (2 mg/kg) VO BID for 7 days, metoclopramide (0.3 mg/kg) VO BID also for 7 days and furosemide (1 mg/kg) PO BID until further instructions while awaiting for test results. The next appointment was scheduled for ten days later but the owner came back for consultation only 60 days after the first visit. The patient had then a history of abdominal distension, dullness and polydipsia. During physical examination, it was possible to notice pale mucous membranes, dehydration, cachexia, hypothermia and ascites. The animal was then hospitalized for additional tests, abdominocentesis, support treatment and further observation. Laboratory findings showed liver failure. The patient died after two days. Necropsy revealed macroscopic alterations compatible with liver cirrhosis. On microscopic examination, it was observed marked diffuse proliferation of fibrous connective tissue and epithelial cells of the bile ducts, besides moderate multifocal histiocytic infiltrate with granular intracytoplasmic brownish pigment. Copper determination on hepatic fragment was performed. The examination found 1320 mg/g on dry weight of copper in the body. The necropsy report was liver cirrhosis associated with copper accumulation. Discussion: Liver disease associated with copper accumulation has been reported in West Highland Terriers, Skye Terriers and Bedlington Terriers. There are not, however, reports of this disease in American Pitbull Terriers. Laboratory findings of this case are consistent with liver failure, also reported by previous studies. Based on laboratory findings supportive care was established since the patient was in an irreversible condition. A biopsy was not performed, despite being the definitive diagnostic method for cirrhosis, since the patient had alterations in the coagulation tests, preventing the procedure. The acquired portosystemic shunt observed on necropsy was due to increased intrahepatic resistance, caused by fibrosis and is a common finding in cases of cirrhosis. The copper concentration found in the liver was three times greater than the value considered normal for the canine species. However, it was not possible to determine whether the copper accumulation was the cirrhosis' cause or consequence. Chronic liver disease is common in veterinary care, but it is often difficult to identify the cause of injury. The copper accumulation should be considered as a liver failure cause in same breeds as predisposed but yet unreported, especially in young patients.

Decreased expression of cardiac troponin C is associated with cardiac lesions in Amorimia exotropica poisoned cattle / Expressão diminuída de troponina cardíaca C associada com lesões cardíacas em bovinos intoxicados por Amorimia exotropica

The plants which cause sudden death of cattle in Brazil occupy a leading position for losses in the cattle industry. Amorimia exotropica is one of the plants pertaining to this group. Diagnostic findings in these cases may be inconclusive; further knowledge is necessary. This paper identifies cardiac lesions through anti-cardiac troponin C (cTnC) immunehistochemistry performed in tissues from cattle poisoned after consumption of A.exotropica in southern Brazil. Heart fragments from nine A. exotropica-poisoned cattle were studied immunohistochemically using anti-human cTnC as the primary antibody. In the hearts from all of the poisoned cattle, there was a sharp decrease in the cTnC expression level in the cytoplasm of groups of cardiomyocytes. A significant decrease in anti-cTnC immunoreactivity occurred particularly in degenerated or necrotic cardiomyocytes. Occasional groups of cells showed complete loss of immunolabeling. In the remaining intact cardiomyocytes from poisoned cattle and in cardiomyocytes from six cattle that died from other causes there was intense cytoplasmic staining.(AU)

No Brasil, plantas cujo consumo determina morte súbita de bovinos estão entre as principais causas de perdas na pecuária. Esse trabalho identifica lesões cardíacas através de imuno-histoquímica antitroponina cardíaca C (TncC), desenvolvida em tecidos de bovinos intoxicados após consumo de Amorimia exotropica, no sul do Brasil. Fragmentos cardíacos de nove bovinos intoxicados, naturalmente, por Amorimia exotropica foram examinados por imuno-histoquímica anti-TncC, como anticorpo primário. Nos corações de todos os bovinos intoxicados pela planta, havia pronunciada diminuição dos níveis de expressão de TncC no citoplasma de grupos de cardiomiócitos. Diminuição significativa na imunorreatividade anti-TncC ocorreu, particularmente, em cardiomiócitos degenerados ou necróticos. Grupos ocasionais de células mostraram completa perda de imunomarcação. Em cardiomiócitos remanescentes e intactos de bovinos intoxicados e em cardiomiócitos de seis bovinos que morreram por outras causas, observou-se intensa coloração citoplasmática.(AU)

Colite histiocítica ulcerativa em um cão boxer no Brasil / Histiocytic ulcerative colitis in a Boxer dog in Brazil

Background: Histiocytic ulcerative colitis (HUC), also known as granulomatous Boxer’s colitis or colitis similar to Whipple’s disease is a condition affecting especially Boxer dogs. The disease is characterized by chronic increase in the defecation frequency, tenesmus, fetid dark-brown stools with blood streaks and mucus. Histopathology of a colorectal biopsy confirms the clinical diagnosis, when infiltrates of markedly PAS-positive macrophages are observed in the colonic lamina propria and submucosa. This communication reports a case of histiocytic ulcerative colitis in a Boxer dog in Brazil. Case: A Boxer dog, with one year and three months of age had been presenting, since it was nine months old, increased frequency of defecation, tenesmus, intermittent diarrhea, loose stools with streaks of liquid blood, and coprophagy; however, no weight loss or appetite loss were noticed. After an initial period of three months experiencing the aforementioned signs, the dog started with persistent diarrhea with bright red blood, mild prostration, weight loss, and voracious appetite. Because of continuous deteriorating condition and treatment refractoriness, the dog was euthanized. At necropsy, the colon was decreased in size with thickened mucosa and foci of ulceration, apart of enlarged mesenteric lymph nodes. Tissue fragments were collected and fixed in 10% formalin, processed following standard procedures for histopathology, and stained with Hematoxylin-Eosin (HE). Selected sections from samples of intestines and mesenteric lymph nodes were also stained with Periodic Acid Shiff (PAS) and Brown-Hopps adapted Gram Staining. Microscopic findings in the colon included infiltration with rounded to oval bulky macrophages, with eccentric nuclei and abundant eosinophilic and slightly granular cytoplasm. These macrophages were distributed in the basal lamina propria and submucosa, and there also was diffuse infiltration of lymphocytes and plasma cells. Extensive multifocal mucosal ulcerations with exposure of the submucosa were also observed. The cytoplasm of macrophages was strongly marked when stained by Periodic Acid Schiff. Macrófagos do cólon e do linfonodo mesentérico não coraram pela técnica de Gram. Discussion: This diagnosis of histiocytic ulcerative colitis was based on the clinical and pathological findings, especially the association of the clinical signs with the infiltrates of markedly PAS-positive macrophages within the colonic lamina propria and submucosa, which is considered a typical characteristic of the condition. The disease afflicts mainly young Boxer dogs, as it was recorded here. In most cases, there is neither weight loss, nor appetite loss, and the hair coat maintains a healthy appearance. However, in chronic cases such this described here, the dogs may show wasting. Ultrastructural and immunohistochemical findings in macrophages of HUC have indicated the participation of Escherichia coli in the etiopathogeny of the disease. The Boxer dog’s predisposition to HUC has been attributed to a hereditary abnormality that confers invasion and persistence of an adherent E. coli group. This paper reports the importance of the histiocytic ulcerative colitis as an enteric condition affecting Boxer dogs also in Brazil.

Colite histiocítica ulcerativa em um cão boxer no Brasil / Histiocytic ulcerative colitis in a Boxer dog in Brazil

Background: Histiocytic ulcerative colitis (HUC), also known as granulomatous Boxers colitis or colitis similar to Whipples disease is a condition affecting especially Boxer dogs. The disease is characterized by chronic increase in the defecation frequency, tenesmus, fetid dark-brown stools with blood streaks and mucus. Histopathology of a colorectal biopsy confirms the clinical diagnosis, when infiltrates of markedly PAS-positive macrophages are observed in the colonic lamina propria and submucosa. This communication reports a case of histiocytic ulcerative colitis in a Boxer dog in Brazil. Case: A Boxer dog, with one year and three months of age had been presenting, since it was nine months old, increased frequency of defecation, tenesmus, intermittent diarrhea, loose stools with streaks of liquid blood, and coprophagy; however, no weight loss or appetite loss were noticed. After an initial period of three months experiencing the aforementioned signs, the dog started with persistent diarrhea with bright red blood, mild prostration, weight loss, and voracious appetite. Because of continuous deteriorating condition and treatment refractoriness, the dog was euthanized. At necropsy, the colon was decreased in size with thickened mucosa and foci of ulceration, apart of enlarged mesenteric lymph nodes. Tissue fragments were collected and fixed in 10% formalin, processed following standard procedures for histopathology, and stained with Hematoxylin-Eosin (HE). Selected sections from samples of intestines and mesenteric lymph nodes were also stained with Periodic Acid Shiff (PAS) and Brown-Hopps adapted Gram Staining. Microscopic findings in the colon included infiltration with rounded to oval bulky macrophages, with eccentric nuclei and abundant eosinophilic and slightly granular cytoplasm. These macrophages were distributed in the basal lamina propria and submucosa, and there also was diffuse infiltration of lymphocytes and plasma cells. Extensive multifocal mucosal ulcerations with exposure of the submucosa were also observed. The cytoplasm of macrophages was strongly marked when stained by Periodic Acid Schiff. Macrófagos do cólon e do linfonodo mesentérico não coraram pela técnica de Gram. Discussion: This diagnosis of histiocytic ulcerative colitis was based on the clinical and pathological findings, especially the association of the clinical signs with the infiltrates of markedly PAS-positive macrophages within the colonic lamina propria and submucosa, which is considered a typical characteristic of the condition. The disease afflicts mainly young Boxer dogs, as it was recorded here. In most cases, there is neither weight loss, nor appetite loss, and the hair coat maintains a healthy appearance. However, in chronic cases such this described here, the dogs may show wasting. Ultrastructural and immunohistochemical findings in macrophages of HUC have indicated the participation of Escherichia coli in the etiopathogeny of the disease. The Boxer dogs predisposition to HUC has been attributed to a hereditary abnormality that confers invasion and persistence of an adherent E. coli group. This paper reports the importance of the histiocytic ulcerative colitis as an enteric condition affecting Boxer dogs also in Brazil.(AU)