Periorbital angioleiomyosarcoma in dog, case report

Abstract

A 3-year-old, male, German shepherd dog was presented with a unilateral, progressively enlarging subcutaneous mass around the left eye. A series of diagnostic tests were performed based on the suspicion of neoplasia. Ultrasonography revealed a large hyperechoic structure with a soft tissue density behind the affected eye. No fluid or polymorphonuclear cells were detected on fine needle aspiration, however, lymphocytes and unidentifiable cells that were potentially neoplastic were observed. Exenteration surgery was done, and several samples were obtained for histopathologic examination. Histopathologically, the tumor mass consisted of high cellular interlacing bundle of pleomorphic, plump spindle to round cell that blended into muscular layer of vessels included arteries, veins, capillaries, and thin cleft-like vascular spaces. Tumor cells nuclei were cigar-shaped in well-differentiated areas and pleomorphic oval to round in poorly differentiated areas. Mitotic figures were frequently observed (38 mitoses per 10 high power fields). Immunohistochemical staining revealed strongly positive staining of cytoplasm of tumoral cells for vimentin and alpha smooth muscle actin, and negative for desmin, S100, and myogenin. On the basis histopathological and immunohistochemical finding, diagnosis of periorbital angioleiomyosarcoma was made. Angioleiomyosarcoma has not been reported previously in periorbital tissue in dogs.