Accessory and Cavitated Uterine Mass (ACUM) in an 18-Year-Old Woman: A Case Report and Literature Review

Background Accessory and cavitated uterine mass (ACUM) is a rare uterine anomaly newly recognized as a form of developmental Mullerian anomaly, which represents a non-communicating uterus-like mass within an otherwise normal uterus. It is a benign gynecological disease associated with severe dysmenorrhea and chronic pelvic pain, which is most common in young nullipara women, and sometimes develops in parous women. Clinical manifestations combined with imaging examinations including ultrasonography (USG), magnetic resonance imaging (MRI), and hysterosalpingography (HSG) are the means to establish a correct diagnosis. Medical therapy is only marginally effective, but laparoscopic surgery for complete mass excision is a feasible technique to relieve patient’s symptoms. Our article is aimed to report a case of ACUM in an 18-year-old woman and summarize the diagnostic criteria of ACUM. Case presentation : An 18-year-old woman was admitted for severe pain in the right lower abdomen during menstruation, which lasted more than 1 year. The patient was misdiagnosed with focal adenomyosis at our hospital on March 4, 2021. After 4 months, she was diagnosed with ACUM. Once diagnosis as focal adenomyosis, nonsteroidal anti-inflammatory drugs (NSAIDs) and gestrinone were administered to the patient. Following the diagnosis of ACUM, she received laparoscopic surgery. Our follow-up indicated that the symptom was significantly relief without drug therapy after sixty days postoperatively. Conclusions Clinical manifestations and imaging examinations are used to establish the diagnosis of ACUM. Medical therapy is only marginally effective, but laparoscopic surgery for complete mass excision is a feasible technique to solve the pain symptom. The prevalence and pathogenesis of ACUM and its reproductive outcomes on patients remain unclear, which calls for more and deeper research to study.