A case report on ACUM: a rare mullerian anomaly

Accessory and cavitated uterine mass (ACUM) is a rare, newly recognized mullerian anomaly. It is an accessory cavity lined by functional endometrium within an otherwise normal uterine cavity, in contrast to the other mullerian anomalies in which the uterus is malformed. It is often misdiagnosed as myoma, adenomyosis or adenomyoma. The entity needs expertise to diagnose as it is a rare but treatable cause of severe dysmenorrhea and chronic pelvic pain in young females with a wide range of differential diagnosis. A 30 years old female with history of one abortion 2 years back, came to infertility OPD with complaints of lower abdominal pain with severe dysmenorrhea, dyspareunia and inability to conceive since 2 years. Her menstrual cycle was regular with normal flow. USG pelvis showed subserosal fibroid of 4×3 cm in fundus region of uterus. On HSG, bilateral fallopian tubes were patent. MRI-pelvis revealed normal uterus with thick walled cavitatory lesion of size 4.1×3.6 cm with thick T2W hypointense wall similar to myometrium in continuation with right fundal wall of uterus containing blood products suggestive of ACUM. Both ovaries were normal, no obvious adnexal lesion/collection/free fluid noted in peritoneal cavity. Laparoscopy followed by laparotomy with excision of ACUM was performed. The MRI findings of an accessory cavitated uterine mass located below the attachment of round ligament with haemorrhagic contents, normal shaped uterus with normal bilateral tubes and ovaries should suggest the diagnosis of ACUM pre-operatively.