Ovarian melanoma metastases are very rare. The case of a 53-year-old female patient with a history of abdominal mass is presented. The magnetic resonance study showed a mass in the pelvis. The histopathological diagnosis was right ovarian cystadenoma with melanoma metastasis. Patient had a history of melanoma of the skin of the abdomen.

Melanoma is a highly malignant neoplasm of the skin and mucous membranes. It is known for its strange and unpredictable behavior, mainly a history of long periods of rest and remissions, ending with rapid progression of recurrence as well as spreading patterns.[1] Melanomas of the female genital tract represent only 3% of all melanomas and ovarian melanomas, secondary or primary, are very rare. [2]

53-year-old female patient, resident in Guatemala, with a history of abdominal mass. History of melanoma on the skin of the abdomen, treated with chemotherapy and radiotherapy in the previous 5 years. Among the laboratory studies, negative tumor markers were found; Pap smear was negative for malignancy. She underwent an imaging study, which revealed a pelvic mass.

A laparotomy was performed with resection of the pelvic mass. The pathological study showed a cystic mass measuring 15 x 14 cm, which when cut contains hemorrhagic material and blood clots; The internal surface had several nodulations of 0.5 x 1 cm, dark brown. Uterine tube showed no abnormalities. In the histological study, a cystic mass wall with old and recent hemorrhage was observed, plus foci of nodular lesions formed by atypical spindle cells, with hyperchromatic nuclei and a moderate amount of cytoplasm; some with melanin pigment (Figure 1A). In immunohistochemistry, the cells showed positivity for Melan-A and HMB45 (Figure 1 B and C). The final diagnosis was cystadenoma with melanoma metastasis. The type of cystadenoma could not be defined due to neoplastic necrosis changes.

Source: San Juan De Dios General Hospital, Department of Pathology

Figure 1. A. Spindle cells, hyperchromatic nuclei and melanin pigments. B. Melan-A expression, diffuse and strong. C. Expression of HMB45, strong and diffuse.

Primary malignant melanoma arising from the ovary is extremely rare and is most associated with benign cystic teratomas. [2][3][4] Secondary spread of the disease, which initially presents as an ovarian tumor, is rare [2].

As the remission period of a malignancy is unpredictable and possibly long, an adequate history is essential to arrive at the correct differential diagnosis. Diagnostic difficulties abound, tumor marker levels are not discriminatory in the majority of patients[2]. In our case we had the advantage that we knew the history of melanoma.

A recent series of 23 cases identified 12 cases of metastatic ovarian melanomas, predominantly observed in women in the reproductive age group, the most common primary site being skin. The interval between primary cutaneous melanoma and metastatic ovarian tumor ranged from 15 to 28 months; The macroscopic appearance of cystic, hemorrhagic masses with friable and necrotic areas was common, [3] as were the characteristics found in our case.

Diagnostic difficulties also arise histologically, as the tumors do not have a uniform appearance and can be confused with germ cell and stromal and sex cord tumors; Therefore, we believe that both a good histological study and immunohistochemical studies help for a definitive diagnosis. The most useful antibodies are S-100, HMB-45 and Melan-A. [2,3] We encountered these difficulties, which is why these studies were performed to confirm the diagnosis.