Primary malignant melanoma arising in a cystic teratoma
A 75-year-old postmenopausal woman was admitted with gall stones and was incidentally found to have a mass in her abdomen. She had no significant gynecologic history. Epigastric tenderness was noted during the general physical examination. The pelvic examination revealed a 20×10 cm, smooth, mobile, nontender cystic mass to the anterior aspect of the uterus. An ultrasound examination showed a pelvic mass measuring approximately 17×11 cm with mixed echogenicity and a thin septation, with no ascites. Computed tomography (CT-scan) revealed a multi-lobulated 19×15 cm cystic mass with calcification and fat, suggesting a teratoma. The mass was located centrally in the pelvis, appearing to originate from the right side of the uterus with no enlarged lymph nodes (). A 1-cm-sized gall stone was also seen. The tumor marker, CA-125, level was elevated at 56.60 IU/mL (range, 0 to 35 IU/mL), and levels of carcinoembryonic antigen and alpha feto-protein were normal. A frozen section of the ovarian tissue at the time of the laparoscopy suggested a malignant tumor of unknown type. As such, the patient underwent a laparoscopic total hysterectomy with bilateral salpingo-oophorectomy with partial omentectomy with cholectystectomy. The diagnosis of a malignant melanoma in an ovarian cystic teratoma was made by histologic examination. Grossly, the right ovary showed a 20×14 cm sized cyst and was solid in appearance, containing sebaceous material. Microscopically, an infiltrating area of atypical pleomorphic cells having macronucleoli and melanin pigments was found in the background of the mature cystic teratoma (). These pleomorphic cells were positive for melan A () and HMB 45 ().\nThe patient was re-evaluated, and the possibility of a melanoma at any other site, mainly skin, central nervous system, eye and gastrointestinal tract, was ruled out. Postoperatively, she received adjuvant immunotherapy with high-dose interferon (IFN)-α. Twelve months after the operation, a metastatic lesion of the liver was diagnosed. The patient underwent two cycles of Dacarbazine and two cycles of Cisplatin-Vinblastine-Dacarbazine chemotherapy. The patient died 17 months after the initial diagnosis.