Metastatic melanoma of the vulva identified by peritoneal fluid cytology

Malignant melanoma of the vulva is an uncommon disease, with a significant portion of cases demonstrating metastasis to inguinal lymph nodes with potential distal spread. Identification of such metastases often requires fine-needle aspiration or biopsy. The cytologic diagnosis of metastatic vulvar melanoma from peritoneal effusions has not been previously described. We present the case of a 54-yr-old woman who underwent en bloc radical vulvectomy with bilateral inguinal lymphadenectomy for melanoma of the right labium minora. No evidence of metastatic disease was identified, and all surgical margins were free of tumor. Despite chemotherapy, the patient returned approximately 2 yr later with abdominal pain and distention. Computed tomography revealed marked ascites and three hepatic lesions. Cytologic examination of the ascites revealed recurrent, metastatic melanoma. Although very rare, metastatic melanoma of the vulva may present as a malignant effusion. In such an event, the diagnosis may be rendered by exfoliative cytology.