ABSTRACT. 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. KEY WORDS: adenocarcinoma, leiomyoma, rabbit.J. Vet. Med. Sci. 69(9): 981-984, 2007 In tumors of the uterus, adenocarcinoma of the endometrium and leiomyoma are the most common spontaneous neoplasm in pet rabbits [5,9,13]. Adenocarcinoma (10 cases, 21.3%) was the most frequently observed, followed by leiomyoma (4 cases, 8.5%) of the 47 rabbits with uterine disorders [13]. A report presented a 79% prevalence of adenocarcinoma among the uterine tumors in rabbits over 5 years of age [3]. However, to the author's knowledge, a mixture of two different kinds of tumors in pet rabbits has not been previously reported. This report describes the pathologic, and immunohistochemical features of an admixture of adenocarcinoma of the endometrium and leiomyoma in the uterus of a pet rabbit.A 7-year-old female rabbit was referred to the Kitamori animal hospital with bloody vaginal discharge. Clinical examination showed hard palpable abdominal masses. Abdominal radiography demonstrated some masses in the abdominal cavity. As uterine tumors were found during laparotomy, the animal was given an ovariohysterectomy. The uterus with tumor masses and the ovaries were fixed in 10% formalin, and were submitted to the Pathology Division of Mitsubishi Chemical Safety Institute Ltd., for histopathologic examination. Several transverse sections over the tumor masses and the uterine wall were prepared. Tissues were processed routinely and embedded into paraffin blocks. Four-micrometer-thick sections were cut and stained with hematoxylin and eosin (HE) and reticullin silver impregnation. Immunohistochemical stains were performed using steam antigen retrieval in citrate buffer (pH 6.0) and a labeled streptoavidin-biotin system (LSAB2 System-HRP, Dako Japan Ltd., Kyoto, Japan). Primary antibodies were mouse monoclonal...

A 7-year-old female boxer dog died suddenly without any clinical signs. It was suspected that the dog had arrhythmogenic right ventricular cardiomyopathy (ARVC) due to ventricular premature complexes and ventricular tachycardia at 3 years of age. The final diagnosis of ARVC was confirmed by histological characteristics, such as loss of cardiocytes and fibrofatty replacement, occurring in the right and left ventricular walls. In the cardiocytes, non-lipid vacuoles were observed. Cardiac fibrosis and intimal thickening of the small arteries occurred without fatty replacement in the inner muscle layer including the papillary muscles of the left ventricular wall. This paper describes the pathomorphological details of an ARVC case with coincidental cardiac fibrosis in the inner muscle layer of the left ventricular wall.

A dog developed a cervical mass, and computed tomography verified a mass surrounding the trachea with some pulmonary masses. Histopathologically, the cervical mass was composed of malignant neoplastic cells showing follicular appearance which reacted positive for thyroglobulin on immunohistochemistry. A characteristic feature of the tumor was abundant and metaplastic stromal components. Anastomosed collagenous tissues connecting to capsule of the tumor were abundant in the stroma. In parts of the collagenous tissues, mature cartilages and bones were continuously formed. There was no cellular atypia or invasion in the components. We diagnosed this case as follicular thyroid carcinoma with metaplastic stroma. This is the first case report that characterizes stromal components with chondroid and osseous metaplasia in a canine thyroid carcinoma.

A ten-year-old neutered male Beagle dog was presented with a one-year history of intermittent limb swelling. Some parts of the skin were so swollen that they erupted, and the tick oily substance drained from them. Cytological examination of the draining substance revealed necrotic fat tissue. It led to suggest that panniculitis caused the substance to be there. Radiograph of the left femur showed periostitis. A diagnosis of pancreatic disease was made on the findings of marked elevation of plasma lipase concentration and ultrasonographic identification of the mass in the pancreatic area. A pancreatic mass was resected and it was histopathologically diagnosed as a pancreatic exocrine carcinoma. This is a rare case of pancreatic disease with panniculitis and periostitis.