Clinical history: A 61-year-old female presents with a pelvic mass. A hysterectomy, bilateral salping-oophorectomy and omentectomy were performed for definitive diagnosis.
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Discussion and answer
Microscopically, adenocarcinoma invades the right and left ovarian surface and parenchyma, small bowel serosa and omentum. The malignant glandular architecture ranges from tubular to complex glands. The nuclei are elongated to round, hyperchromatic with pseudostratification. Rare intracellular mucin vacuoles are seen. Extensive “dirty-type” necrosis is prominent. Tumour cells are positive for CK20 and CDX2 and negative for CK7, ER, PR and CA125. The diagnosis is metastatic colon adenocarcinoma.
The patient had a right hemicolectomy one year ago and was diagnosed with a pT4 pN1 colon adenocarcinoma. She was on chemotherapy when the bilateral ovarian masses developed. Metastatic colon carcinoma to the ovary occurs in 4% of women with colon cancer and may be misdiagnosed as a primary ovarian tumour. Tumours are bilateral in 60% of patients and may present as solid/cystic masses. The microscopic features include: a prominent desmoplastic response, glands with cribriform pattern and “dirty-type” necrosis. Mucin containing goblet cells are infrequently seen.
Immunohistochemistry usually shows the following profile: CK7-, CK20+, CDX2+, CEA +. Primary ovarian mucinous adenocarcinomas are usually unilateral and less commonly exhibit extensive “dirty-type” necrosis. These tumours are usually CK7+ and CK20+ with variable CDX2 positivity.