USMLE PRACTICE QUESTION OF THE WEEK

Question for February 20, 2026

A 42-year-old woman comes to the clinic with progressive abdominal distension and early satiety for 3 months. She has no history of liver disease. She has smoked 1 pack/day for 20 years and drinks socially. Family history includes breast cancer in her mother. On exam, she has shifting dullness, a palpable fluid wave, and bilateral adnexal masses. CA-125 is elevated. Abdominal ultrasound confirms ascites and complex ovarian masses bilaterally.

Which of the following is the most likely diagnosis?

Correct Answer:

C. Serous cystadenocarcinoma

Correct Answer Explanation:

This woman with bilateral ovarian masses, ascites, and elevated CA-125 most likely has epithelial ovarian cancer, specifically serous cystadenocarcinoma. Endometriomas (“chocolate cysts”) are benign. Mature teratomas are benign germ cell tumors. Theca-lutein cysts are related to pregnancy/ovulation induction.

Further Insight:

  • Epithelial ovarian cancers are often bilateral and diagnosed late due to nonspecific symptoms.
  • Risk factors: BRCA mutations, nulliparity, early menarche, late menopause.