Lipid rich carcinoma and solid carcinoma in mammary gland of a dog: histopathologic and immunohistochemical features

Lipid rich carcinoma is rare in dog and women and is characterized by cells that have an abundant foamy cytoplasm. A 10 year old, mix breed female dog suffered two subcutaneous masses in ventral abdomen was referred to surgery department of veterinary hospital of Ahvaz Shahid Chamran University. Surgical excision and microscopic examination of masses were done. After grading by Elston and Ellis method, histochemical staining was performed such as PAS, Cong red and Oil Red O. Immunohistochemical detection of pKi67, P53, cerbB2 and factor VIII – related antigen were carried out. Microscopically, the masses were two parts; first compose of big cells with vacuolated cytoplasm and euchromatin nuclei and second part cells with scant cytoplasm and pleomorphic nuclei and obvious membrane. Grade of tumor was Grade III, poorly differentiated. Positive reaction was seen in vacuolated cytoplasm for Oil Red O. Neoplastic cells of lipid rich area demonstrated intense immunoreactivity for pKi67. All tumor cells lacked p53 and c-erbB2. This is the first report of coincidence of lipid rich carcinoma and solid carcinoma in a dog with description of histopathologic and immunohistochemical characteristics.