A Case of Subcutaneous Mast Cell Tumor and Vascular Invasion in a Four-Toed Hedgehog

Abstract

A hand-reared female Four-toed Hedgehog (Atelerix albiventris), aged 6 years old, had a subcutaneous mass on her neck. We conducted a histopathological examination of several organs, including the mass, in a post mortem. The mass comprised individual, round neoplastic cells, which had round nuclei exhibiting anisokaryosis and occasional basophilic intracytoplasmic granules. Toluidine blue staining revealed that these granules showed metachromasia. Immunohistochemically, the cytoplasm and cell membrane of the neoplastic cells were positive for KIT (CD117). Based on these histopathological findings, the mass was diagnosed as a mast cell tumor. Metastatic foci were not detected in any other organs. Neoplastic mast cells were observed in the blood vessels of the liver and uterus, suggesting peripheral circulation of neoplastic cells.