Imaging features of accessory cavitated uterine mass (ACUM): a peculiar yet correctable cause of dysmenorrhea.

Accessory cavitated uterine mass (ACUM) is a rare form of developmental mullerian anomaly which causes chronic pelvic pain, dysmenorrhea and infertility in young females. It is a non-communicating, accessory cavity within an otherwise normal uterus, lined by functional endometrium and surrounded by myometrium-like smooth muscle cells which imparts it uterus-like appearance. USG and MRI are the imaging modalities which help in reaching the diagnosis. Knowledge of this entity and awareness of its imaging features can help diagnose this often underdiagnosed and surgically correctable cause of dysmenorrhea.