A 35-year-old woman presents with a unilateral ovarian mass. Histology shows a multilocular cyst lined by tall columnar cells with basally located nuclei and abundant intracellular mucin. Immunohistochemistry shows CK7 positive and CK20 negative. Which is the most likely diagnosis?
- A Primary ovarian mucinous carcinoma ✓
- B Ovarian serous cystadenoma
- C Metastatic colorectal adenocarcinoma
- D Ovarian mature cystic teratoma
Correct answer: A. Primary ovarian mucinous carcinoma
Explanation
Primary ovarian mucinous tumors are typically CK7 positive and CK20 negative, distinguishing them from metastatic gastrointestinal adenocarcinomas which are usually CK7 negative and CK20 positive. The histology described (tall columnar cells with intracellular mucin) is classic for a mucinous neoplasm.
Reference: Robbins and Cotran Pathologic Basis of Disease, 10th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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