This tumour displays the common histologic characteristics of adult type granulosa cell tumor. Granulosa cell tumour is a low‐grade malignancy of the ovary, containing various cells of the ovarian follicle. Granulosa cell tumours vary greatly in size, and occur over a wide age range.

The tumor consists of neoplastic granulosa cells in a fibrothecomatous background. The cells themselves have scant eosinophilic cytoplasm and oval nuclei with a longitudinal groove (a so called "coffee bean nucleus"), minimal atypia and relatively few mitoses (often less than 5/10 HPF). The nuclei are typically central with a single prominent nucleolus.

Various patterns can be observed, occasionally with multiple patterns present in the same tumour; in particular, trabecular, microfollicular, macrofollicular, insular, gyriform, watered silk and pseudopapillary patterns can be seen. The microfollicular pattern exhibits Call-Exner bodies which are follicle-like structures filled with acidophilic material.

By immunohistochemistry, inhibin, calretinin, CD99, CD56, SF1 and FOXL2 are typically positive in an adult granulosa cell tumour.

See Related Content for references:

1) Sun, HD., et al. Gynecol Oncol. 124(2):244-9, 2012
2) Al-Agha, OM., et al. Am J Surg Pathol. 35(4):484-94, 2011
3) Ganesan, R., et al. Int J Gynecol Pathol. 30(5):452-9, 2011