Primary ovarian melanoma arising from ovarian teratomas are rarely reported and difficult to accurately diagnose. Cases in the literature rely on a diagnosis of exclusion, and cases of primary ovarian melanoma with pathologic evidence of melanoma in situ are exceedingly rare. We report a case of a 66-yr-old female who presented to emergency department with abdominal pain and bloating. Computed tomography scan showed a 21 cm complex pelvic mass. An urgent laparoscopic bilateral salpingo-oophorectomy was performed. Pathologically the mass was identified as a mature teratoma. Within the cystic teratoma, there was an area showing a sheet arrangement of atypical cells. Those atypical cells were positive for Melan A, Sox10, HMB45, and c-KIT, and negative for PD-L1. Melanoma in situ was present in both the squamous and ciliated columnar epithelium. The melanoma was negative for PD-L1, and no BRAF (codon 600, exons 11, 14, and 15) or c-KIT (exons 2, 9, 10, 11, 13, 14, 15, 17, 18) mutations were identified, thus supporting the so-called triple negative malignant melanoma. A thorough dermatologic exam was conducted and only a 3 mm skin basal cell carcinoma was confirmed on biopsy. At 11 mo of follow-up, the patient is disease free and doing well and no metastatic melanoma has been identified. To the best of our knowledge, this is the first documented case of a primary ovarian melanoma arising in a mature teratoma with evidence of melanoma in situ present in both ciliated columnar and squamous epithelium in a patient with synchronous skin basal cell carcinoma. Our case is positive for c-KIT protein (CD117) by immunohistochemistry, but negative for KIT mutation. More case reports are needed to further characterize the disease.
Copyright © 2021 by the International Society of Gynecological Pathologists.