A puzzling pelvic passenger: case report of a wandering splenunculus.

A pelvic accessory spleen is a rare congenital anomaly. The majority of accessory spleens are found at the splenic hilum. This unusual localization may result in diagnostic uncertainty and may be an exceedingly rare cause of pelvic pain. This article reports the case of an accessory spleen presenting as a symptomatic left adnexal mass. The mass was removed laparoscopically and histological assessment revealed the mass to be an accessory spleen. An accessory spleen is not uncommon and would be of no clinical concern in the vast majority of patients. However, a pelvic accessory spleen is a rare condition and its presence can confound the typical differential diagnosis for pelvic pain. While a pelvic accessory spleen is not a typical cause of pelvic pain, this case report teaches the value of a broad differential diagnosis and continuing further investigations when there remains diagnostic uncertainty.