A case of xanthoma in a Saanen goat

This report describes a case of a subcutaneous xanthoma of the sacral region in a 2-year-old female Saanen goat. The tan-coloured mass was 8.5 cm × 4.0 cm × 0.5 cm in size. Yellow-white areas were present across the cut surface. Histopathologically, the mass was composed of foamy macrophages, numerous giant cells, abundant lipid material and cholesterol clefts. The structure consisted of lobular areas surrounded by a stroma. Tissue sections were negative for bacteria, fungi and mycobacteria. Frozen tissue from the mass stained positively with Oil Red O, confirming lipid accumulation in both the extracellular spaces and the large foamy macrophages. Immunohistochemically, the mass was positive for vimentin, proliferating cell nuclear antigen and CD68, but negative for smooth muscle actin, glial fibrillary acidic protein and S100 protein antibodies. As the animal was presented dead, it was not possible to analyse blood lipid levels. To the authors' knowledge, this is the first report of a xanthoma in a goat.     

Fibrosarcoma arising at the site of a retained surgical sponge in a cat

Abstract: An 8‐year‐old female spayed domestic shorthair cat had an abdominal mass palpated as an incidental finding on physical examination. Cytologic findings in ultrasound‐guided fine‐needle aspirates of the mass were most compatible with a sarcoma, with abundant mineralized material and mixed inflammation. The mass was removed surgically and on gross examination was white‐tan, firm, associated with the mesentery, and when transected contained a gauze sponge in its center. On histopathologic examination, an area of central necrosis with mineralization and numerous refractile fibers consistent with sponge material was surrounded by dense fibrous connective tissue (gossypiboma). Within the connective tissue was a population of highly pleomorphic spindle cells consistent with a fibrosarcoma. Immunohistochemically, most neoplastic cells stained strongly positive for vimentin and a low number of cells were positive for smooth muscle actin. The results were consistent with a fibrosarcoma arising at the site of a retained surgical sponge. At a follow‐up visit 2 months postoperatively, ultrasonographic and cytologic evidence of metastasis was found in the spleen and mesentery. To our knowledge, this is the first report of malignant transformation at the site of a retained surgical sponge in a cat and the first report of a fibrosarcoma arising within a gossypiboma in a domestic animal.     

Congenital cystic polypoid rectal hamartoma in a newborn foal

A neonatal foal with signs of rectal bleeding was diagnosed with an intraluminal rectal mass and intussusception on surgical exploration of the abdomen. Histologically, the mass consisted of cystic spaces lined by simple columnar epithelium with numerous goblet cells and was surrounded by thin bands of smooth muscle in a myxomatous stroma. Although the mass shared similarities with retrorectal cystic hamartoma (tailgut cyst) and juvenile polyps, described in human medicine, location and histologic findings were not entirely consistent with either condition.     

Hypertrophic gastropathy associated with gastric sarcoma in a dog

A 14-y-old spayed female Labrador Retriever was presented with an 8-mo history of chronic vomiting. Abdominal ultrasound and gastrointestinal endoscopy revealed a mass protruding into the gastric lumen, with cytologic features suggestive of sarcoma. A partial gastrectomy was performed; the gastric body and antrum were thickened, with a cerebriform appearance of the mucosal surface. Histologic examination revealed a submucosal neoplastic proliferation of fusiform cells variably arranged in irregular bundles and scattered whorls. Fusiform cells strongly reacted to antibodies against vimentin, S100, and neuron-specific enolase; glial fibrillary acidic protein was moderately and multifocally expressed. Pancytokeratin, KIT, α–smooth muscle actin, and desmin were nonreactive. Histologic and immunohistochemical findings suggested a diagnosis of gastric sarcoma with features referable to a non-GIST (gastrointestinal stromal tumor), non–smooth muscle NIMT (non-angiogenic, non-lymphogenic intestinal mesenchymal tumor). The overlying gastric mucosa was thickened by elongated and dilated gastric glands, predominantly lined by intensely periodic acid-Schiff–stained mucous cells. This altered mucosal architecture was suggestive of Ménétrier-like disease. Although this disease has been hypothesized to predispose to gastric adenocarcinoma in dogs, an association with gastric sarcoma has not been documented previously in the veterinary literature, to our knowledge.     

Vaccine-associated rhabdomyosarcoma with spinal epidural invasion and pulmonary metastasis in a cat

A 7-year-old, female, domestic medium-haired cat had a recurrent deep dermal mass in the interscapular region after initial surgical removal 3 months earlier. The cat had received a killed rabies vaccine and a five-in-one vaccine in the same area about 2 months prior to the first surgery. The relapsed mass was diagnosed as vaccine-associated sarcoma. The cat was euthanized 2 months later because of hind limb paralysis. At necropsy, multiple, poorly demarcated, nodular masses were seen in the muscles around the shoulders, neck, and thoracic vertebrae. Pulmonary metastasis and spinal epidural invasion at T1-T3 with regional cord compression and malacia were observed. Microscopically, the masses consisted of interwoven bundles of spindle cells with prominent multinucleated giant cell formation. The neoplastic cells stained strongly positive for myoglobin, and moderately but variably positive for vimentin, desmin, and alpha- smooth muscle actin. Phosphotungstic acid-hematoxylin staining revealed cytoplasmic striations in scattered tumor cells. The tumor was considered a vaccine-associated rhabdomyosarcoma.     

Primary ureteral giant cell sarcoma in a Pomeranian

An 8-year-old male neutered Pomeranian dog was presented to the Veterinary Teaching Hospital at Oregon State University for surgical treatment of hydronephrosis of the left kidney and a left cranial abdominal mass. A primary ureteral mass was found during exploratory surgery, and the mass was resected and ureteral anastomosis was performed. Cytologic evaluation of the mass revealed 3 distinct cell populations, including a large number of multinucleated giant cells, a moderate number of thin spindle-shaped cells, and cohesive clusters of transitional epithelial cells. The cytologic diagnosis was giant cell sarcoma. The diagnosis was confirmed by histologic examination, and immunohistochemical staining was performed. The spindle-shaped cells and multinucleated giant cells were both immunoreactive for vimentin and spindle-shaped cells for S-100. Tumor cells did not express wide-spectrum cytokeratin, broad-spectrum muscle actin, smooth muscle actin, sarcomeric actin, desmin, BLA36, Mac 387, synaptophysin, neuron-specific enolase, glial fibrillary acid protein, or von Willebrand factor. These findings are most consistent with an anaplastic sarcoma with giant cells. This is the first case report of a primary ureteral giant cell sarcoma in a dog.     

Synovial sarcoma in an Ayrshire heifer

An 8-month-old Ayrshire heifer had a rapidly growing mass in the axillary region of the left thoracic limb. The mass surrounded the distal humerus and entrapped nerves of the brachial plexus, causing an abnormal gait. Histologically, the mass was composed of clusters and cords of round to polygonal cells with scattered, spindle-shaped cells. The neoplastic cells stained positively for vimentin and cytokeratin. No staining was found with S-100 protein, kappa and lambda light chains, or T-cell markers by immunohistochemistry. On electron microscopic evaluation, the cytoplasm of the neoplastic cells contained few organelles, principally rough and smooth endoplasmic reticulum and mitochondria. This synovial sarcoma has histologic and ultrastructural features characteristic of the poorly differentiated subtype of synovial sarcoma in the human classification system.     

Rhabdomyosarcoma associated with the lead wire of a pacemaker generator implant

An 11‐year‐old female spayed Labrador Retriever was presented for a draining, painful subcutaneous mass palpated over a previously implanted pacemaker generator. Infection was suspected and the mass was removed surgically. On cut surface, the mass was friable and mottled tan to brown with firm pale tan nodules, surrounding the pacemaker lead wire adjacent to the pacemaker generator. Cytologic interpretation of impression smears was consistent with a sarcoma, and suggestive of a rhabdomyosarcoma due to the presence of strap‐like cells. On histopathologic examination, a highly invasive nodular mass surrounded the pacemaker lead, composed of pleomorphic round, spindle and strap cells, and multinucleated giant cells. The population exhibited microscopic invasion into the deep portion of the fibrous capsule surrounding the pacemaker generator. There were tumor emboli within small to medium subcutaneous veins adjacent to the mass. Immunohistochemically, the neoplastic cells stained positive for α‐sarcomeric actin and vimentin, and negative for α‐smooth muscle actin, consistent with a rhabdomyosarcoma arising at the site of the pacemaker generator. To our knowledge, this is the first report of a rhabdomyosarcoma associated with the lead wire of a pacemaker generator in a dog.     

What is your diagnosis? Perifemoral mass in a cow

Abstract: A 15‐year‐old female Simmental cross‐breed cow was presented to the Purdue University Veterinary Teaching Hospital for evaluation of a perifemoral soft tissue mass. Impression smears made from an excisional biopsy contained a population of pleomorphic mesenchymal cells with abundant, periodic acid–Schiff‐positive (PAS), intracytoplasmic granular material, and rare elongated multinucleated cells consistent with strap‐like cells. A second population of small round cells suggestive of lymphocytes or progenitor cells was also noted. A cytologic diagnosis of sarcoma was made, with rhabdomyosarcoma considered most likely based on the large amount of PAS‐positive material (presumed to be glycogen) and the rare strap‐like cells. Histopathologic sections contained an unencapsulated, densely cellular neoplasm composed of haphazardly arranged highly pleomorphic mesenchymal cells and a few small round cells. The mesenchymal cells were positive for vimentin, non‐specific muscle actin, and myoglobin, and negative for phosphotungstic acid‐hematoxylin, smooth muscle actin, and desmin. Glycogen granules were confirmed by transmission electron microscopy. A diagnosis of pleomorphic rhabdomyosarcoma was made. While cytologic findings may suggest rhabdomyosarcoma, cytologic features can be highly variable, and a definitive diagnosis usually requires cytochemical and immunohistochemical staining.     

Myofibroblastic sarcoma of the pleura in a pig

An intrathoracic sarcoma from a 7-month-old female pig was studied by light and electron microscopy and immunohistochemistry. The tumor tissue of varied cell density consisted chiefly of spindle-shaped cells, some of which grew around blood vessels in a concentric fashion. Many tumor cells were positive for alpha smooth muscle actin and not for desmin, though some cells were reactive for both antigens. A majority of tumor cells had ultrastructural features characteristic of myofibroblasts, but a few cells resembled vascular smooth muscle cells in the synthetic state. This neoplasm may have arisen from vascular smooth muscle with features indicating a transition to myofibroblasts.     

Undifferentiated tumor in the ovary of a corn snake (Elaphe guttata guttata)

A 6-year-old intact female corn snake (Elaphe guttata guttata) was presented with a 3-week history of anorexia. Coelomic radiographs revealed a 9 x 4 cm soft tissue opacity suggestive of a right ovarian enlargement. The mass (9 x 5 x 4 cm) was surgically removed, and multiple smears from tissue sections were stained with Diff-Quik. Multiple tissue samples from the mass were collected and fixed in formalin. Cytologic specimens were moderately cellular and contained light pink amorphous background material. The cells were primarily spindle-shaped with moderate to marked anisocytosis and anisokaryosis. Cells sometimes were round to polygonal, and rarely were arranged in small clusters. Macrophages occasionally were observed. Histologic specimens consisted of a highly cellular mass composed of pleomorphic, spindle-shaped cells and, occasionally, round to polygonal cells arranged in irregular fascicles. The neoplastic cells were immunoreactive for cytokeratin (AE1/AE3), smooth muscle actin, and skeletal muscle actin, but did not stain for vimentin or desmin. On the basis of the morphologic and immunohistochemical results, a diagnosis of ovarian undifferentiated carcinoma was made. In this report, we describe the challenges of using immunohistochemistry to diagnose this uncommon type of tumor in reptiles.     

Vulvar leiomyosarcoma in a cat

A vulvar leiomyosarcoma was diagnosed in an 8-year-old mixed-breed, sexually intact cat. The cat had a history of vulvar swelling, bleeding and stranguria. The mass was located at the ventral commissura of the vulva. The cut surface of the mass was lobulated and greyish-white, with areas of necrosis and haemorrhage. Histologically, it was a spindle-cell sarcoma consisting of interlacing bundles of very elongated neoplastic smooth muscle cells and variably dense collagenous matrix separated by individual cells or streams. It also contained areas of focal necrosis and haemorrhage. The mitotic index ranged from seven to 12 mitoses per 10 high-power fields. Immunohistochemically, the spindle-shaped neoplastic cells were strongly positive for smooth muscle actin (SMA) and vimentin, whereas no immunoreactivity was obtained for desmin. The vascular elements of the internal control tissue also exhibited strong SMA and vimentin immunoreactivity. Based on the morphological and immunohistochemical features, the tumour was classified as a leiomyosarcoma.     

酶消化法分离培养肉鸡肺动脉平滑肌细胞

试验旨在探讨胶原酶消化法分离并培养肉鸡肺动脉平滑肌细胞(pul monary artery smooth muscle cell,PASMC)的方法。将1～7日龄雏鸡的肺动脉中膜剪成小于1 mm2的组织块,0.1%Ⅱ型胶原酶消化分离PASMC并进行原代培养和传代培养。倒置显微镜下观察培养细胞的形态,对培养细胞进行HE染色和光学显微镜观察,并采用抗α-肌动蛋白单克隆抗体(α-Smooth muscle actin)免疫组化染色法检测细胞胞浆内α-肌动蛋白的表达,用以鉴定所培养的细胞。结果表明,倒置显微镜下细胞为长梭形,呈典型的"峰—谷"状,未见明显异型细胞。α-actin胞浆染色阳性细胞数占总细胞数的97%以上。因此,胶原酶消化法可用于分离培养肉鸡PASMC,且有方法简单,成活细胞数多、传代周期短的特点,可用于肉鸡心血管疾病如肺动脉高压和肺血管重构的研究工作。     

Rhabdomyosarcoma in the abdominal cavity of a 12-month-old female donryu rat

Neoplasms of skeletal muscle origin are very rare in the rat. Recently, we experienced a case of rhabdomyosarcoma as a white mass involving the junction of the esophagus and stomach in the abdominal cavity of a 12-month-old female Donryu rat. Histopathologically, the neoplastic cells composing the mass invasively spreaded from the lamina propia to the tunica serosa in the stomach as well as the esophagus. Although the neoplastic cells varied in appearance, pleomorphic atypical cells with abundant eosinophilic cytoplasm were prominent. Some tumor cells were stained blue with phosphotungstic acid hematoxylin. The nuclei of spindle-shaped neoplastic cells were arranged longitudinally like beads. Multinucleate giant cells and mitotic figures were also frequently observed. Immunohistochemically, these neoplastic cells were positive for desmin and myoglobin, whereas they were negative for alpha-smooth muscle actin. Taken together these findings, this tumor was diagnosed as a pleomorphic rhabdomyosarcoma, probably derived from the muscle layer of the lower part of the esophagus. This is the first report of rhabdomyosarcoma in a Donryu rat.     

Uterine angiolipoleiomyoma in a dog.

An 11-year-old crossbred Pomeranian bitch displayed a large intramural, well-delineated uterine mass in one horn, near the junction with the uterine body. The mass was composed largely of mature adipose tissue, smooth muscle cells singly and in small clusters, anomalous medium-size and large arteries, and multifocal islands of cartilaginous and osseous tissues. Smooth muscle cells stained positively for desmin, and adipocytes and chondrocytes were positive for S-100 protein. This tumor has histologic and immunohistochemical features compatible with human uterine angiolipoleiomyoma, a rare tumor that has never been reported in the veterinary literature. This benign tumor is believed to be of a choristomatous nature.     

Humeral Chondrosarcoma in a Hokkaido Brown Bear (Ursus arctos yesoensis)

Humeral chondrosarcoma was found in an 18-year-old male Hokkaido brown bear (Ursus arctos yesoensis). Necropsy revealed a large firm mass under the left superficial pectoral muscle at the axillary region. The mass involved the left shoulder joint and peripheral muscles, and connected to the head of the humerus with osteolysis. Histopathologically, the mass was composed of irregularly shaped myxomatous to cartilaginous tumor lobules. The tumor cell showed moderate nuclear atypia with a relatively high mitotic index, especially in the edges of the myxomatous lobules. The tumor cells were positively immunostained with vimentin and S-100 protein. Based on these findings, the tumors were diagnosed as chondrosarcoma. Metastases were found in the left axillary lymph node, lungs, liver and kidney.     

Ultrastructural morphologic evaluation of the phenotype of valvular interstitial cells in dogs with myxomatous degeneration of the mitral valve

OBJECTIVE: To evaluate morphologic changes in valvular interstitial cells of dogs and to find evidence for disease-associated phenotypic changes in these cells. ANIMALS: 5 clinically normal dogs and 5 dogs with severe mitral valve endocardiosis. PROCEDURE: Mitral valve leaflets were evaluated by use of transmission electron microscopy. Differences in cell type and cell location were identified. RESULTS: A change in cell type toward a myofibroblast or smooth muscle cell phenotype was detected, with the smooth muscle cell type being most common. These cells had long amorphous cytoplasmic extensions, fibrillar cytoplasm, incomplete basal lamina, few mitochondria, and eccentrically placed nuclei but lacked smooth endoplasmic reticulum or Golgi complexes. Remaining valvular interstitial cells had heterochromatic nuclei and produced only minimal quantities of collagen. Compared with normal valves, myxomatous valves ha many interstitial-like cells located adjacent to the endothelium. Deeper within the abnormal valves, cells with a heterogenous phenotype formed groupings that appeared to be anchored to adjacent collagen. CONCLUSIONS AND CLINICAL RELEVANCE: Myxomatous degeneration of the mitral valve in dogs is associated with phenotypic alteration, changing from an interstitial to a mixed myofibroblast or smooth muscle cell phenotype. A closer association between interstitial cells and the endothelium is evident in diseased valves. In response to the disease process, valvular interstitial cells of dogs appear to change toward a smooth muscle phenotype, possibly in an attempt to maintain valve tone and mechanical function.     

A case of adenocarcinoma of the endometrium extending into the leiomyoma of the uterus in a rabbit

In a pet rabbit, 2 tumor masses one on each horn were macroscopically seen in the wall of the uterus. On light microscopic examination, the right horn mass consisted of an admixture of neoplastic epithelial and mesenchymal element. The epithelial element was composed of neoplastic epithelial cells with numerous mitotic figures and formed varied sizes of acini, glandular, and solid structures. The tumor was diagnosed as an adenocarcinoma of the endometrium. The mesenchymal element was composed of well-differentiated smooth muscle cells and was diagnosed as a leiomyoma. While adenocarcinoma cells formed a protrusive mass in the uterine lumen, they also showed an extension into the leiomyoma of the myometrium. By immunohistochemistry, adenocarcinoma stained positive for cytokeratin (MNF116) and leiomyoma stained positive for smooth muscle actin, showing a substantial difference in the cytological nature of these tumor cells. The results may give a further evidence supporting the narrative of the tumor development that an adenocarcinoma of the endometrium extended into leiomyoma of the uterus. To the author's knowledge, this is the first report describing this type of combination of two independent tumors in a pet rabbit.     

Gamna‐Gandy bodies: a case of mistaken identity in the spleen of a cat

A 4‐year‐old, female spayed Domestic Shorthair cat was presented for a 2‐day history of lethargy, anorexia, and vomiting. Diagnostic assessments revealed a severe, regenerative anemia and the presence of a solitary, 3 × 4 cm splenic mass. Cytologic examination of fine‐needle aspirates of the splenic mass showed sheets of pleomorphic histiocytic cells with numerous intracellular and extracellular, negatively staining to deeply basophilic, branching structures. These structures were typically of thin uniform thickness with random angled branching that formed geometrical shapes and fragments, occasionally with sharpened ends and a crystalline appearance. Septal‐like divisions were irregularly spaced along some of the linear branches. The cytology was interpreted as a probable histiocytic inflammatory response to the unidentified foreign material with histiocytic sarcoma as a differential diagnosis. Histopathologic evaluation of the splenic mass resulted in a diagnosis of histiocytic sarcoma. The branching material stained positively for both iron and calcium, indicating that the material was compatible with Gamna‐Gandy bodies present secondary to tumor‐associated hemorrhage and the formation of calcium–iron complexes.     

Histology and immunohistochemistry of seven ferret vaccination-site fibrosarcomas

The anatomical location, histology, and immunohistochemistry of 10 ferret dermal and subcutaneous fibrosarcomas were examined. Seven of the 10 tumors were from locations used for vaccination. All fibrosarcomas contained spindle-shaped cells surrounded by variable quantities of connective tissue stroma. However, vaccination-site fibrosarcomas (VSFs) subjectively contained a higher degree of cellular pleomorphism. Multinucleated cells were present in three of seven VSFs but not in any of the nonvaccination-site fibrosarcomas (NVSFs). Large histiocytic cells, interpreted as macrophages, containing intracytoplasmic basophilic granular material were observed in two VSFs but not in any of the NVSFs. Five VSFs contained peripheral lymphoplasmacytic aggregates. Immunohistochemically, three VSFs stained with anti-smooth muscle actin antibodies and one stained with antibodies against desmin. No expression of muscle cytoskeletal filaments was observed in any NVSF. Filaments interpreted as actin were visible in both the VSFs examined ultrastructurally. One of the VSFs examined ultrastructurally contained intracytoplasmic crystalline material. The preferential development of subcutaneous fibrosarcomas in vaccination sites suggests that, as in cats, vaccination may promote local sarcoma development in ferrets. Additionally, some of the histologic, immunohistochemical, and ultrastructural features of these tumors are similar to those reported for feline vaccine-associated sarcomas. To the authors' knowledge, vaccination has not previously been reported to be oncogenic in any species other than cats.