Canine hemangiopericytoma in a young native Ghadrejani dog: histopathological and immunohistochemical diagnosis

A sixteen-month-old male Ghadrejani dog was referred to the veterinary clinic with a swelling mass on the first finger of the right hand. Clinical examination revealed swelling, erythema and alopecia with ulceration. CBC, radiographs of the affected area and chest, and regional lymph node examination were reported as normal. Histopathological examination revealed a subcutaneous, multilobular, unencapsulated but well-circumscribed tumor with a fingerprint pattern of spindle cells arranged around a central capillary. Immunohistochemical analysis showed that the neoplastic cells expressed vimentin and did not express α-smooth muscle actin (SMA) and S100 protein. Based on the histopathological and immunohistochemical findings, the tumor was diagnosed as canine hemangiopericytoma (CHP). This is the first report of CHP in a young indigenous Ghadrejani dog. This report demonstrates that not only can CHP occur in young dogs, but that differentiation from other soft tissue sarcomas requires not only histopathological findings but also immunohistochemical examination.