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Supplemental material, sj-pdf-1-vet-10.1177_03009858221087630 for Gastrointestinal stromal tumors with Kit gene mutation in 4 guinea pigs (Cavia porcellus) by Kengo Ueda, Masamine Takanosu, Yumiko Kagawa, Akiko Ueda, Naoko Ano, Kohji Nomura and Kiyokazu Ozaki in Veterinary Pathology

A tumor had formed in the right eye of a 14-year-old male chinchilla. The black-and-white-colored tumor occupied the entire eye except for the lens and had invaded extensively inside the orbit. Histologically, round, spindle- to polygonal-shaped tumor cells had proliferated in a solid-sheet arrangement. The tumor cells exhibited polymorphic nuclei ranging from round- to polygonal-shaped, as well as abundant cytoplasm, which occasionally contained melanin granules. In some areas, several cells were surrounded by the basal lamina. Additionally, the tumor showed cervical lymph-node metastasis. Upon immunostaining, the tumor cells were positive for epithelial markers (cytokeratin AE1/AE3, 8/18, and 20), S100, and vimentin. Consequently, we diagnosed primary pleomorphic iridociliary adenocarcinoma with lymph-node metastasis. This is the first report of iridociliary adenocarcinoma in chinchillas.

Despite being rarely reported, improved diagnostic and prognostic indicators are necessary for treating malignant melanoma in rabbits. In this study, two cases of primary skin lesions, on the scrotum and on eyelid, with systemic metastases, were examined. The tumors formed intra-dermally by sheet-like proliferation of polymorphic cells, with anisocytosis and varying amount of melanin granules. Tumors had displaced almost 50% of the lung and liver tissue, and tumor metastasis was the cause of early death in both rabbits. Ki-67-positive population was high in both, and it was found to be useful in assessing the outcome and malignancy. In addition, Melan-A, HMB-45, PNL2 and S100 established a useful immunohistochemical panel for the diagnosis of melanocytic tumor in rabbits.

Oral and esophageal candidiasis sometimes leads to mucosal hyperplasia, and progresses to carcinoma. We have produced an animal model for hyperplastic mucosal candidiasis in the forestomach that has a proliferative lesion of the squamous epithelium with chronic inflammation and C. albicans infection, some of which advanced to squamous cell carcinoma. There are many reports of the antibacterial effects of probiotics, but consensus about their antifungal effect has not been reached. In the present study, we investigate whether probiotic (yogurt) containing Lactobacillus gasseri OLL2716 (LG21 yogurt) can prevent proliferative and inflammatory changes caused by C. albicans in this mucosal candidiasis animal model. Diabetes was induced in 8-week-old WBN/Kob rats by intravenous administration of alloxan. One group of diabetic rats received a saline containing C. albicans and LG21 yogurt orally (DC+LG21 group) for 30 weeks, and another group received only C. albicans (DC group) for 30 weeks. They were sacrificed at 40 weeks of age, and analyzed histopathologically. In the DC+LG21 group, squamous hyperplasia at the greater curvature was significantly milder, and the Ki-67 positive index was significantly lower compared with the DC group. Suppurative inflammation with C. albicans also tended to be suppressed at the greater curvature. These findings suggest that probiotic (yogurt) containing Lactobacillus gasseri OLL2716 can suppress squamous hyperplastic change and inflammation associated with C. albicans infection in the forestomach.