Pelvic retroperitoneal paraganglioma mimicking an ovarian mass

A 75-year-old hypertensive woman was referred with ultrasound findings of a 40 x 35 mm semi-solid right adnexal mass and right hydroureteronephrosis. She complained of headache and right-sided back pain. Computed tomography demonstrated a cystic adnexal mass that did not appear to originate from the right ovary and grade 2 hydroureteronephrosis. Magnetic resonance imaging indicated that the mass originated from the right ovary. Tumor markers were in the normal range. Exploratory laparotomy was performed to determine the origin of the lesion, and revealed a retroperitoneal mass obstructing the right ureter. The mass was completely removed and and the histopathologic diagnosis was paraganglioma.