Malignant melanoma metastatic to the ovaries: a clinicopathological and immunohistochemical study of four cases

Abstract

Introduction: Ovarian involvement with malignant melanoma (MM) is extremely rare often leading to a misdiagnosis of ovarian cancer. We present the clinicopathological and immunohistochemical features of four cases of ovarian metastatic MM diagnosed at our Department over a 23-year period (1989–2011). Materials and Methods: The patients’ age ranged from 28 to 72 (mean 49.5) years. All presented with a pelvic mass and a past history of MM (three cutaneous, one anorectal), although at the time of the histopathological evaluation it was known in only two cases. The interval between the primary and ovarian MM ranged from 3 to 72 months. The initial treatment was surgery, followed by chemoimmunotherapy in three of them. One patient died of an unrelated cause 29 months following surgery with metastatic disease, while the other three died from metastatic disease within 41 days, 15 months, and 10 years, respectively. Two of these patients had lymph node metastases previously and all three had synchronous metastases at other sites at the time of the surgery. Results: The ovarian tumors were unilateral, varied in size from 14 to 25 cm, and only two were grossly pigmented. Histologically, they were composed of large epithelioid cells with eosinophilic cytoplasm, small cells, spindle-shaped cells, or a combination. The predominant architectural patterns were nodular in one, and diffuse in the other three tumors. Immunostains for S-100, HMB-45, and melan-A were positive in all tumors tested. Conclusion: The presented cases illustrate the clinical variability and unpredictable biologic behavior of ovarian metastatic MM and emphasize the value of immunohistochemistry in establishing the diagnosis.