Non-Ovarian Pelvic Cyst: Not Specific Enough

A 39-year-old unmarried woman was referred for evaluation following an incidental ultrasound finding of a 5 4 cm pelvic cyst with a thick hyperechoic wall. Otherwise, her gynecological, medical, and surgical history was unremarkable. Her clinical examination was unremarkable. She was mildly obese with a body mass index of 32. There was no abdominal tenderness or palpable masses. Bimanual vaginal examination was not performed (as is the custom in Muslim countries for unmarried women). Tumor markers cancer antigen (CA)-125, human chorionic gonadotropin, lactate dehydrogenase, and alpha-feto-protein were all negative. Magnetic resonance imaging (MRI) of the pelvis showed a normal uterus and endometrium [Figure 1]. Both ovaries were normal. There was a well-defined, irregular pelvic mass lesion, measuring 4.5 3.8 3.5 cm compressing the bladder dome, but not arising from it. It was of mixed signal intensity on T2-weighted images and was of relatively thick hypointense wall, could represent hemosiderin or calcification. There was a small amount of fluid in the solid mass that was not enhancing on postcontrast examination. There was no ascites or pelvic lymph node enlargement. The MRI concluded that it was a pelvic mass, with no clear attachment to any of the pelvic organs. The most likely possible differential diagnoses were: urachal cyst, degenerated pedunculated subserous fibroid, peritoneal inclusion cyst, and ovarian dermoid cyst.