Imaging Manifestations of Accessory Cavitated Uterine Mass—A Rare Mullerian Anomaly

Abstract

Context Accessory cavitated uterine mass (ACUM) is an uncommon and under-recognized entity with distinct imaging characteristics and causing significant patient distress. Differentiating it from its other clinical and radiological differentials is therefore extremely important and prevents delay in surgical management which is the treatment of choice. Aims The aim of the study is to describe the MRI appearance of the surgically and pathologically proven ACUM cases from our institution in the last 2 years. Settings and Design This is a retrospective study in a tertiary care hospital in South India. Methods and Material We reviewed the clinical presentations and imaging findings of seven surgically proven cases of ACUM qualifying the proposed diagnostic criteria. Results All patients presented with chronic pelvic pain, dysmenorrhea, and prolonged post-menstrual pain. MRI in all seven cases showed an intramural, noncommunicating, and cavitating lesion near the uterine cornua with internal contents similar to that of endometrioma. Although the cavity was lined by endometrium in all the cases (proven in pathology), it was well appreciable on MRI in only five cases. The rest of the uterine myometrium and main endometrial cavity were normal with no features of adenomyosis. Conclusion MRI is a reliable diagnostic tool for accurate diagnosis of ACUM, and more importantly, in distinguishing it from other causes of chronic pelvic pain like adenomyosis and endometriosis and other imaging differentials like adenomyoma, noncommunicating uterine horn, and degenerating leiomyoma.

Accessory cavitated uterine malformation: Enhancing awareness about this unexplored perpetrator of dysmenorrhea

“…13,49,54,56 • The normal endometrial cavity has no communication with the accessory cavity. 48 • A consistent ring of myometrial tissue with the same signal as the junctional zone surrounds the core hemorrhagic cavity. 13 • On T2-weighted imaging, the thin inner lining of the cavity will appear hyperintense, indistinguishable from the endometrium, and somewhat enhanced after gadolinium contrast.…”

“…• ACUM typically presents on MRI as a large, well-circumscribed, round mass inside the external myometrium, with a cystic, hemorrhagic inner layer and a thick, fibrous crown. 10,13,46,48,49,54,55 • This solid, nodular mass is placed laterally to the uterus, caudal to the insert round ligament, and cranial to insertion of the uterine artery. 13,49,54,56 • The normal endometrial cavity has no communication with the accessory cavity.…”

“…8,12,14,16,21,22,[47][48][49][50][51] The fluid-containing cavity and the myometrial mantle are the two defining characteristics of ultrasound. 6,12,14,[47][48][49] • The fluid in the accessory cavity was either echogenic (ground glass appearance) or hyperechoic. 3,4,9,14,22,49,50 However, this may be misdiagnosed, considering the prevalence of endometrioma among young women.…”

Accessory cavitated uterine malformation (ACUM): A hidden face of dysmenorrhea

“…Spherical-shaped cavitated lesion containing echogenic fluid surrounded by the myometrial mantle. 8,13,14,42,[44][45][46][47][48][49][50] 2. The myometrial mantle and the fluid-filled cavity are the defining features of ultrasound.…”

“…The normal endometrial cavity, along with a normal size uterus, and there is no communication with the normal endometrial cavity. 57 4. The central hemorrhagic cavity is surrounded by a regular ring with the same signal as the junctional zone.…”