Primary leiomyoma of the ovaries in a dog / 동물의과학연구지

We would like to report a case of leiomyoma of the ovaries in a dog. Leiomyoma is commonly seen in the vagina in dogs. However, it is a very rare neoplasm in the ovaries. As there have only been a few reported cases, this report provides valuable information on veterinary medicine and pathology. Masses found in the ovaries need to be differentiated from other ovarian tumors. Therefore, we describe the gross, histopathological, and immunohistochemical features of a case of ovarian leiomyoma in a 10-year-old female Yorkshire Terrier dog. The mass on the right of the uterus was found accidentally by pelvic ultrasonography. Laparatomy revealed a large multi-nodulated ovarian mass. Grossly, cut surfaces of the mass showed multiple firm whitish nodules in the cortex and bloody loose connective tissue in the medulla. Histopathologically, the cortex of the mass was composed of spindle cells forming interlacing fascicles. The cells had elongated, blunt-ended nuclei and eosinophilic cytoplasm as detected by hematoxylin and eosin staining. Immunohistochemical stained sections were immunoreactive for alpha-smooth muscle actin and desmin but negative for vimentin and S-100. Therefore, differential diagnosis confirmed leiomyoma based on morphology and positive staining for alpha-smooth muscle actin and desmin.

A case of metastatic cholangiocarcinoma in a ferret / 동물의과학연구지

Cholangiocarcinoma is a relatively rare neoplasm in animals and humans. A four-year-old, neutered male ferret presented with depression, anorexia, cachexia, diarrhea, and icterus. Necropsy findings included ascites, multiple white nodules on the surface of the liver, stomach, and duodenum, gross enlargement of the bile duct and right atrium, hemorrhage of the gastric and duodenal mucosa, and icterus of the mesenteric fat. Infiltrative well-differentiated neoplastic biliary epithelial cells forming ducts and acini with a prominent collagenous stroma were observed on microscopic examination of neoplastic lesions within the liver, mesentery, and the serosa of the stomach and duodenum. This is a report on a rare case of obstructive jaundice due to cholangiocarcinoma in a ferret.

Chronic pyometra due to bilateral ovarian tumors in a South American sea lion / 동물의과학연구지

A 14-year-old female South American sea lion (Otaria byronia) with persistent vaginal secretion and chronic hemorrhagic diarrhea was encountered. During postmortem examination, the uterus was found to resemble a balloon with mucosal congestion and was filled with grayish milky material. The ovaries also had abnormal features, including necrotic surface lesions and multiple whitish foci in the cut section. Hemorrhages and ulcerated changes due to toxemia were observed in other organs, including the liver, spleen, lung, intestines, and lymph nodes. Microscopically, the left ovary contained interlacing fascicles of fibroblast-like cells with blunt-end nuclei showing cytoplasmic positive immunoreactivity against alpha-smooth muscle actin and desmin. The right ovary contained cells with round to cigar-shaped nuclei showing cytoplasmic positive immunoreactivity against vimentin. In conclusion, based on classification of bilateral ovarian tumors as a leiomyoma in the left region and a fibroma in the right region, this sea lion was diagnosed with chronic closed pyometra.

Case of Sporadic T-cell Lymphosarcoma in Cattle / 동물의과학연구지

We would like to report a case of bovine lymphosarcoma. Parous cattle from a livestock farmhouse were examined for mutinodular masses in the abdominal cavity after slaughter. For clinical signs, animals presented mild leukemic signs but did not have viral or bacterial infection. Grossly, whitish to yellowish smooth masses similar to fat tissue were covered with a thin membrane. A multilobulated mass formed around the arteri, and there was a large quantity of reddish fluid on the cut surface. Histopathologically, a monomorphic population of lymphocytes was observed along with small amounts of cytoplasm, round nuclei with coarsely granular chromatin, and numerous mitotic figures in the samples. In the tumor lesion, uniformly round cells had invaded with abundant neovascularization. Especially, the immunohistochemical phenotype of tumor cells was positive for anti-CD3 and negative for anti-CD8 and anti-CD20. Therefore, morphological analysis diagnosed the mass as a multinodular bovine lymphosarcoma of T-cell origin without any sign of infection by a viral agent.