Vulvar encapsulated solid papillary carcinoma with neuroendocrine differentiation: a case report.

A 40-year-old woman underwent excision of a painless left vulvar mass. The specimen showed a well-circumscribed mass measuring 3.5 × 2.7 × 2.5 cm. Microscopic examination exhibited an encapsulated neoplasm with a solid and papillary growth pattern. The tumor cells were oval to columnar and showed moderate nuclear atypia. No capsular invasion was identified. Immunonegativity for calponin and p63 confirmed the absence of myoepithelial cells either within or at the periphery of the tumor. The tumor was immunopositive for gross cystic disease fluid protein 15, synaptophysin, and chromogranin. The histologic and immunohistochemical characteristics were consistent with an encapsulated solid papillary carcinoma with neuroendocrine differentiation. The patient has been free of disease for 4 years after surgery. This is the first report of a vulvar encapsulated solid papillary carcinoma with neuroendocrine differentiation. Correct diagnosis is imperative because of the distinct biologic behavior of the tumor.