Uterine angioleiomyoma in an African green monkey (Chlorocebus aethiops sabaeus)

Background A uterine neoplasm was observed, as an incidental finding, during post‐mortem examination of a 26‐year‐old female multiparous African green monkey (Chlorocebus aethiops sabaeus). The intramural, expansile, 2 to 3 cm well‐demarcated, dark‐red, nodular neoplasm was located on the anterior uterine body (corpus) wall. Methods The mass was examined by light microscopy and by immunohistochemistry. Results The mass was confirmed as a cavernous uterine angioleiomyoma (syn. vascular leiomyoma) characterized by abundant intratumoural vasculature lined by Factor VIII‐positive endothelial cells and surrounded by smooth muscle actin‐positive cell proliferations. Conclusion Angioleiomyoma sharing the characteristics of intramural human cavernous uterine angioleiomyoma should be considered in the differential diagnosis of uterine tumours in non‐human primates.