Case History

A 26-year-old female presents with a 11 cm unilateral ovarian mass and massive ascites. Immunohistochemical test for SMARCA4 / BRG1 shows loss of expression.

Given the H&E morphology and stain result presented above, what is the correct diagnosis?

A. Dysgerminoma
B. Granulosa cell tumor (juvenile)
C. Small cell carcinoma of the ovary hypercalcemic type
D. Lymphome

Correct Answer: C. Small cell carcinoma of the ovary hypercalcemic type

Discussion:

This is small cell carcinoma of the ovary, hypercalcemic type (SCCOHT), an undifferentiated tumor composed of small cells, with or without a large cell component. It is a rare ovarian tumor with poor prognosis, often associated with paraneoplastic hypercalcemia, and occurs in women of reproductive age and children. Tumor cells typically show sheets, nests, cords and trabeculae growth patterns, with or without follicle-like spaces with eosinophilic or basophilic secretions. SCCOHT is molecularly defined by inactivating SMARCA4 mutations.  In this case, the tumor cells show loss of nuclear SMARCA4 / BRG1 immunohistochemical expression.

Case contributed by: Hui Zhang, M.D., Assistant Professor, Women's Health, UAB Pathology