Retrospective Pathological Studies of Splenic Lesions in Domestic Hamsters (Phodopus spp.).

Fifteen splenic biopsy specimens from a total of 212 biopsy specimens and necropsy cases of domestic hamsters (Phodopus spp.) from the Division of Wild (Exotic) Animal Medicine, Veterinary Medical Teaching Hospital, National Chung Hsing University, Taiwan, collected between 2010 and 2017, were studied retrospectively. The incidence of lesions in the spleen was 7.1% (15/212). The mean age of affected hamsters was 16.6 months and females were affected more than males. The lesions consisted of 10 neoplasms and five non-neoplastic lesions. The most common tumours were histiocytic sarcoma (HS), lymphoma, malignant fibrous histiocytoma (MFH) and hemangiosarcoma. Immunohistochemistry revealed the HSs and MFHs to express lysozyme. The lymphomas were negative for CD20; however, one case was positive for CD3 and another was positive for CD79a. The hemangiosarcoma expressed von Willebrand factor. The non-neoplastic lesions were all fibrotic nodules and these were all identified in ageing female hamsters. The nodules consisted of collagen fibres identified with Masson's trichrome stain, and they were related to repair of trauma in the spleen.