Cutaneous extrarenal rhabdoid tumor in a dog: a case report

Abstract

Rhabdoid tumours (RTs) are rare, highly aggressive tumours of undetermined origin in humans, and are sub-classified as renal/extrarenal RTs depending on location. The origins of extrarenal rhabdoid tumours are an enigma and neoplasms have rarely been reported in non-primate species. An 11-year-old male Maltese dog was presented with a submandibular mass. Histologically, the mass was composed of sheets of highly pleomorphic "rhabdoid" cells, further characterised by the presence of large epithelioid cells with globular/fibrillar paranuclear inclusions. Further immunohistochemical analysis revealed that the neoplastic cells were positive for vimentin and desmin similar to human tumours. In addition, ultrastructural analysis showed that the intracytoplasmic inclusions were mainly composed of whorled bundles of intermediate filaments. Our results suggest a useful diagnostic approach to cutaneous, extrarenal rhabdoid tumours in dogs and describe their characteristics.