Abstract

A 57-year-old woman presented with two tender and sub-centimeter, subcutaneous nodules on the occipital scalp. The lesions were clinically suspected to be cysts. Histopathology of both lesions demonstrated perifollicular and periadnexal cords and nests of trabeculated malignant cells in mucinous stroma with vesicular chromatin, scant to moderate cytoplasm, and severe cytologic atypia including nuclear grooves and multinucleation. Single cell apoptosis/necrosis, perineural invasion, as well as frequent and atypical mitoses were identified. Immunohistochemistry was diffusely positive for Inhibin and SF-1. The patient's medical history was significant for primary ovarian adult granulosa cell tumor (AGCT), with a pathognomonic FOXL2 mutation, diagnosed at age 41. The patient had multiple intra-pelvic/abdominal/thoracic recurrences in the prior 16 years. During that time, the tumor underwent high grade transformation. AGCTs account for only 2–5% of all ovarian cancers. Diagnosis at an early stage and successful surgical resection is common, and while prognosis is generally favorable, these tumors have a propensity for late recurrence/metastasis. Almost all AGCTs are comprised of low-grade cells with bland nuclear features, even when these tumors recur or metastasize. High-grade transformation has only been reported in a small number of cases. Distant metastases are similarly uncommon, with most recurrences limited to the intra-abdominopelvic region. Rare intrathoracic and bony metastases have been reported. Our patient ultimately manifested all three. To our knowledge, there have not been prior reports of cutaneous metastasis of this tumor. We herein report a novel clinicopathologic occurrence: AGCT with high-grade transformation, metastatic to the skin. Despite aggressive therapy, this patient died 8 months after initial presentation to dermatology.

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