Atypical polypoid adenomyoma

Atypical polypoid adenomyoma (APA) is a rare benign tumour of the uterus.

Pathology
APAs are characterized by glands with abnormal shapes that: (1) often have squamous metaplasia, and (2) are surrounded by benign smooth muscle. Nuclear atypia, if present, is mild.

The microscopic differential diagnosis includes endometrial carcinoma and endocervical adenocarcinoma.