skip to main content

CUP Peritoneal Müllerian — SCE Medical Oncology MCQ

Instant feedback + full explanation. One question, done properly.

ModerateCancer of Unknown PrimaryCUP Peritoneal MüllerianSCE Medical Oncology

A patient presents with cancer of unknown primary with peritoneal carcinomatosis and elevated CA-125. IHC shows PAX8+, WT1+, CK7+, CK20-. No ovarian mass is identified on imaging. What is the most likely diagnosis and management approach?

Educational content. Not a substitute for clinical judgement or local policy.

Reveal the answer and explanation

Correct answer: D — Primary peritoneal carcinoma (or occult tubo-ovarian cancer) — treat with carboplatin-paclitaxel as per ovarian cancer protocols, with consideration of PARP inhibitor maintenance if BRCA-mutant or HRD-positive

The PAX8+/WT1+/CK7+/CK20- immunophenotype with elevated CA-125 and peritoneal disease is diagnostic of a Müllerian origin (primary peritoneal, tubo-ovarian, or fallopian tube cancer). Primary peritoneal carcinoma is managed identically to advanced ovarian cancer: carboplatin-paclitaxel ± bevacizumab, with PARP inhibitor maintenance guided by BRCA/HRD status. Germline BRCA testing should be offered. Prognosis is similar to stage-matched ovarian cancer.

Reference: NICE NG36 CUP; ESMO 2024 Ovarian Cancer; ESMO CUP Guidelines