Littoral Cell Angiosarcoma in a Dog

SummaryThis report describes the microscopical and immunohistochemical characteristics of littoral cell angiosarcoma in a 12-year-old, neutered female, beagle dog. The dog succumbed to metastatic disease 3 months after diagnosis of a mid-splenic mass. The tumour was characterized by two histological patterns: anastomosing microvascular channels and microvascular papillary fronds. The neoplastic cells expressed both endothelial and histiocytic markers and were erythrophagocytic. Immunohistochemical findings consistent with malignancy were CD34 expression and high Ki67 nuclear immunoreactivity.