Juvenile Cystic Adenomyoma Presenting As Accessory Cavitated Uterine Mass: Radiology-Centric Report Of Two Adolescent Cases And Literature Review

Abstract

Background: Juvenile cystic adenomyoma—now more precisely termed accessory cavitated uterine mass (ACUM)—is an uncommon Müllerian anomaly that mimics rudimentary horn, cystic degeneration of fibroids, and focal adenomyosis. Because teenagers typically present with severe, drug-resistant dysmenorrhoea, prompt radiological recognition is essential to avoid misdirected surgery.

Cases: We describe two otherwise healthy adolescents.

Case 1: An 18-year-old reported right-sided pelvic pain that intensified during menses. Pelvic MRI demonstrates a 2.4 × 1.9 × 2.3 cm ovoid cystic lesion along the right anterolateral uterine fundus. The lesion is hyperintense on both T1‑ and T2‑weighted sequences, contains fluid–fluid levels, and is encircled by a low‑signal rim mirroring the junctional zone. No communication with the endometrial cavity is identified..

Case 2: A 19-year-old with polycystic ovary syndrome presented for escalating dysmenorrhoea. MRI demonstrates a 2.9 × 2.7 × 3.1 cm cystic lesion in the left uterine fundus containing haemorrhagic debris with susceptibility blooming on gradient‑echo sequences. It is separated from the endometrial cavity by intact normal myometrium.

Interventions and Outcomes: Both patients underwent laparoscopic cystectomy. Histopathology confirmed an endometrium-lined cavity within hypertrophic myometrium, consistent with ACUM. Post-operative recovery was uneventful, and each patient reported near-complete symptom resolution at three-month follow-up.

Discussion: Characteristic MRI findings—a solitary haemorrhagic cyst beneath the round-ligament insertion in an otherwise normal-shaped uterus—allow confident diagnosis and differentiation from mimics. Complete laparoscopic excision is curative in most series and preserves fertility.

Conclusion: Awareness of ACUM’s imaging signature in adolescents with severe dysmenorrhoea streamlines diagnosis and directs fertility-sparing, minimally invasive surgery. Early recognition prevents unnecessary radical procedures and offers rapid pain relief.