Abstract
Angiomyofibroblastoma (AMFB) is rarely reported in humans as well as domestic animals, especially in the female genital tract. This painless tumour is characterised by the proliferation of spindle or ovoid tumour cells with myofibroblastic differentiation, which often cluster around thin-walled blood vessels. This report presents a case of feline AMFB for the first time. Preoperative abdominal radiography demonstrated an enlarged uterus with the dorsolateral displacement of the ovaries, and transabdominal ultrasonography showed an enlarged uterus with diffuse hypoechoic areas. The resected uterus showed a firm texture with a grey to brownish colour. A microscopic examination revealed proliferation of well-differentiated neoplastic spindle cells on a background of abundant fibrous stroma containing numerous blood vessels. Myxoid degeneration and vascular extravasation were not observed. The neoplastic cells were diffusely immunopositive for α-SMA and vimentin and focally positive for desmin (in the perivascular areas). AMFB is rare in veterinary medicine and the feline uterine AMFB observed in the present case had not been previously reported. Although previously reported as a safe, benign tumour, a surgical procedure of a large AMFB in small animals without proper diagnosis may become life-threatening.