Clinicopathological and immunological features of pleomorphic rhabdomyosarcoma in the subcutis of a 9-year-old Lolo dog

Abstract

AbstractA 9-year-old female Lolo dog presented with a subcutaneous, large mass protruding from the right-side of her flank region with intact covering skin. Surgical excision of the mass revealed a well demarcated, large firm mass without invading the underlying muscle of the flank. The gross examination revealed a fish-flesh colored, large firm mass, histologically neoplastic cells exhibiting pleomorphism, multinucleated giant cells, and bizarre mitosis. Using immunohistochemical staining, the tumor cell was expressed with vimentin, desmin, and myogenin. Based on histological and immunohistochemical staining, it was confirmed as PRMS. The dog was followed up to 2 years after surgical removal. There was no recurrence, and the dog had normal health. The present case indicated that PRMS had characteristically histological and immunohistochemical features that could be used in differential diagnosis from highly confusing alveolar and embryonal rhabdomyosarcoma in dogs, and it must be included in differential diagnosis of anaplastic sarcoma in adult dogs.