{"paper_id":"d7053a4b-ec9e-44c2-894f-1871f44672db","body_text":"International Journal of Science and Research (IJSR)\n \nISSN: 2319\n-\n7064\n \nImpact Factor 2025: 7.089\n \nVolume 15 Issue 3, March 2026\n \nFully Refereed | Open Access | Double Blind Peer Reviewed Journal\n \nwww.ijsr.net\n \nAccessory Cavitated Uterine Myometrium in a \nPerimenopausal Woman Presenting as a Large \nUterine Mass with Severe Dysmenorrhea: A Case \nReport\n \n \nDr\n. Khazi Naziya Parveen\n1\n, Dr. Nafeesa Farheen\n2\n, Dr. Rashmi Basantsingh\n3\n \n \n1\nOBG PG\n-\n3rd Year, Vydehi Institute of Medical Sciences and Research Centre, Bangalore, Karnataka, India\n \n \n2\nAssociate Professor Dept of OBG, Vydehi Institute of Medical Sciences and Research Centre, Bangalore, Karnataka, India\n \n \n3\nOBG PG, 3rd Year, Vydehi Institute of Medical Sciences and Research Centre, Bangalore, Karnataka, India\n \n \n \nAbstract\n: \nAccessory Cavitated Uterine Myometrium (ACUM) is a rare Müllerian anomaly characterized by an isolated endometrium\n-\nlined cavity within the myometrium. It commonly presents in young women with severe dysmenorrhea and is often misdiagnosed as\n \nadenomyosis or leiomyoma. We report a case of a 43\n-\nyear\n-\nold woman presenting with chronic lower abdominal pain and severe \ndysmenorrhea for three years. She had regular menstrual cycles with prolonged and heavy bleeding. Clinical examination reveal\ned a \nmobile abdominopelvic mass corresponding to 16\n–\n18 weeks gestational size. Imaging suggested a localized intramyometrial lesion. \nSurgical exploration revealed a well\n-\ndefined cavitated lesion within the myometrium containing altered blood. Histopathological \nexamination confirmed the presence of an endometrial lining with surrounding smooth muscle hyperplasia, consistent with ACUM.\n \nThis case is notable for its atypical age of presentation and highlights the importance of considering ACUM in the differenti\nal diagnosis \nof dysmenorrhea associated with uterine enlargement. Surgical management resulted in significant symptomatic relief.\n \n \nKeywords\n: \nAccessory cavitated uterine myometrium, ACUM, dysmenorrhea, Müllerian anomaly, adenomyosis mimic, uterine mass\n \n \n1.\n \nIntroduction \n \n \nAccessory Cavitated Uterine Myometrium (ACUM) is a rare \nand distinct Müllerian anomaly characterized by a non\n-\ncommunicating cystic cavity within the myometrium lined \nby functional endometrium. It is increasingly being \nrecognized as a separate clinical entity distinct from \nadenomyosis and other uterine pathologies.\n \n \nTypically, ACUM presents in adolescents or young women \nwith severe dysmenorrhea that is often refractory to medical \nmanagement. The lesion contains hemorrhagic content due \nto cyclical bleeding within the cavity, leading to progressive \npain.\n \n \nThe etiology is thought to involve duplication or persistence \nof Müllerian tissue during embryological development. \nDespite advances in imaging, ACUM is frequently \nmisdiagnosed due to overlapping features with more \ncommon conditions such as fibroids and adenomyosis.\n \n \nThis report describes an unusual case of ACUM in a \nperimenopausal woman, highlighting the diagnostic \nchallenges and emphasizing the importance of considering \nthis entity even beyond the typical age group.\n \n \n2.\n \nMethodology\n \n \nA 43\n-\nyear\n-\nold multiparous woman presented with \ncomplaints of lower abdominal pain and severe \ndysmenorrhea for three years. The pain was cyclical, \nprogressively worsening, and interfering with daily activities.\n \n \nHer menstrual cycles were regular, occurring every 30 days, \nbut were prolonged with bleeding lasting 10 days. The flow \nwas heavy, requiring approximately six sanitary pads per \nday.\n \n \nOn \nE\nxamination\n \n•\n \nPer abdomen: A well\n-\ndefined, mobile mass \ncorresponding to 16\n–\n18 weeks size was palpable.\n \n•\n \nPer vaginal examination: Uterus was enlarged to 16 \nweeks size, bilateral fornices were free, and no \ntenderness was noted.\n \n \nUltrasonography revealed a bulky uterus with a localized \nintramyometrial lesion. Based on clinical findings, \nprovisional diagnoses included adenomyosis and fibroid \nuterus.\n \n \nThe patient was planned for surgical management. \nIntraoperatively, a well\n-\ncircumscribed cavitated lesion was \nidentified within the myometrium, separate from the \nendometrial cavity. The cavity contained thick, chocolate\n-\ncolored fluid.\n \nSurgical excision of the lesion laparoscopic hysterectomy \nwas performed. The specimen was sent for histopathological \nexamination.\n \n \n3.\n \nResults and Discussion\n \n \nACUM is a rare entity that poses a diagnostic challenge due \nto its resemblance to more common uterine conditions. It is \ndefined by the presence of a cavitated lesion within the \nmyometrium, lined by functional endometrium and \nsurrounded by smooth muscle.\n \nPaper ID: SR26322114652\nDOI: https://dx.doi.org/10.21275/SR26322114652\n1319 \n\nInternational Journal of Science and Research (IJSR)\n \nISSN: 2319\n-\n7064\n \nImpact Factor 2025: 7.089\n \nVolume 15 Issue 3, March 2026\n \nFully Refereed | Open Access | Double Blind Peer Reviewed Journal\n \nwww.ijsr.net\n \nIn this case, the patient presented at 43 years of age, which is \natypical. Most reported cases occur in younger women, \nmaking this presentation unusual and clinically significant.\n \n \nThe clinical findings of an enlarged uterus and severe \ndysmenorrhea initially suggested adenomyosis or fibroid \nuterus. However, intraoperative identification of a localized \ncavity containing altered blood pointed towards ACUM.\n \n \nOperative Findings\n \nEnlarged uterus (~16\n–\n18 weeks size)\n \nWell\n-\ndefined intramyometrial cystic lesion\n \nNo communication with uterine cavity\n \nThin serous fluid of approximately 30ml within cavity\n \n \nHistopathological Findings\n \nMicroscopic examination revealed:\n \nCystic cavity lined by endometrial glands and stroma\n \nSurrounding smooth muscle hyperplasia\n \nAreas of hemorrhage and hemosiderin\n-\nladen macrophages\n \nNo evidence of malignancy\n \nThese findings confirmed the diagnosis of ACUM.\n \n \nDifferential Diagnosis\n \nAdenomyosis (diffuse involvement rather than localized \ncavity)\n \nDegenerating fibroid (absence of endometrial lining)\n \nRudimentary uterine horn (usually communicates or \nassociated with anomalies)\n \n \nManagement\n \nSurgical excision remains the definitive treatment. Removal \nof the lesion leads to complete resolution of symptoms. In \nthis patient, postoperative recovery was uneventful with \nsignificant relief in dysmenorrhea.\n \n \n4.\n \nOperative Photographs (Captions)\n \n \n \nFigure 1:\n \nIntraoperative image showing enlarged uterus \nwith a well\n-\ndefined bulge over the myometrium\n \n \n \nFigure 2:\n \nExcised specimen showing a cystic lesion within \nthe myometrium\n \n \nFigure 3:\n \nCut section of the specimen revealing a well\n-\ncircumscribed cavity lined by endometrial tissue\n \n \n \nFigure 4\n: \nHistopathology Photograph: Surrounding smooth \nmuscle hyperplasia around the cavity (H&E stain)\n \n \n5.\n \nConclusion \n \n \nAccessory Cavitated Uterine Myometrium is a rare and \nunderdiagnosed condition that should be considered in \nwomen presenting with severe dysmenorrhea and uterine \nenlargement. Although commonly reported in younger \npatients, it can also occur in perimenopausal women, as \ndemonstrated in this case.\n \n \nAccurate diagnosis requires a combination of clinical \nsuspicion, imaging, and histopathological confirmation. \nSurgical management is curative and significantly improves \nquality of life.\n \n \nGreater awareness of this entity can help prevent \nmisdiagnosis and ensure timely and appropriate treatment.\n \n \nReferences\n \n \n[1]\n \nAcién P, Acién M. Accessory cavitated uterine mass: a \nnew Müllerian anomaly. Eur J Obstet Gynecol Reprod \nBiol. 2010.\n \n[2]\n \nTakeuchi H, et al. Accessory cavitated uterine mass: a \nrare cause of severe dysmenorrhea. J Minim Invasive \nGynecol. 2006.\n \n[3]\n \nChun SS, et al. MRI findings of accessory cavitated \nuterine mass. AJR Am J Roentgenol. 2012.\n \n[4]\n \nJain N, et al. ACUM: diagnostic dilemma and \nmanagement. J Obstet Gynaecol India.\n \n[5]\n \nGupta N, et al. ACUM mimicking adenomyosis: case \nreport. Case Rep Obstet Gynecol.\n \nPaper ID: SR26322114652\nDOI: https://dx.doi.org/10.21275/SR26322114652\n1320","source_license":"CC0","license_restricted":false}