Accessory and cavitated uterine mass in a perimenopausal woman

A 49-year-old nulliparous woman presented with abnormal uterine bleeding for 6 months.She had history of chronic pelvic pain for the previous 2 years.Transabdominal and transvaginal ultrasonography showed an anteverted uterus measuring 8.9 4.1 4.6 cm and two fibroids.A focal ovoid iso-to hypoechoic mass 42 21 mm was seen along the surface of the left uterine fundus with a partial echogenic rim and abundant vascularity at the margin and inside the mass (Fig. 1).Both ovaries were identified separately and appeared normal.Both cornua were seen.The endometrium measured 10 mm and was uniform, hyperechoic.The endometrial junction was normal and regular.Magnetic resonance imaging of the pelvis with contrast showed a contrast-enhancing mass of 36 24 38 mm, appearing iso-intense to the myometrium on T1/T2 sequences, in the left parametrium abutting the left lateral wall of the uterine body and cornua (Fig. 2).The mass enhanced homogeneously and contained central T2 hyperintensity resembling that of the endometrial cavity.A diagnosis of accessory and cavitated uterine mass (ACUM) was made.Laparoscopic resection of the ACUM was done and histology revealed a cavitated mass lined by functional endometrium with glands and stroma surrounded by irregularly arranged smooth muscle cells positive for oestrogen and progesterone receptors.ACUM is a rare congenital Mullerian anomaly which occurs when a non-communicating accessory cavity lined with endometrium and surrounded by uterine smooth muscle is attached to the normal functioning uterus. 1 The criteria for diagnosing ACUM are: (i) An isolated accessory cavitated mass usually located under round ligament; (ii) A normal uterus, fallopian tubes, and ovaries; (iii) A surgical case with excised mass and pathological examination; (iv) An accessory cavity lined by endometrial epithelium with glands and stroma; (v) Chocolate brown coloured fluid contents; (vi) No adenomyosis in the uterus. 2