Mucosal Malignant Melanoma of Nasal Cavity Recurring a Year After Radiotherapy.

OBJECTIVE: Sinonasal mucosal malignant melanoma is a rare entity. In this report we present a nasal mucosal malignant melanoma case with its histopathological and clinical features.

CASE REPORT: An 88-year-old female patient presented with epistaxis a month ago. Examination revealed a polypoid mass lesion of right nasal cavity originating from the middle concha. Her medical history revealed that she had been found to have a mass lesion in the right nasal cavity 15 months ago. She then underwent a punch biopsy from that lesion. A definitive histopathological diagnosis was not made but it was declared that the lesion had been a malignant epithelial tumor. The patient then had radiotherapy and the lesion showed complete regression. One year after completion of radiotherapy, the lesion recurred. Her last PET-CT showed multiple metastatic foci. Endoscopic excisional biopsy was performed for her recurrent lesion. Fragmented tumoral tissues were measured as 3,6x3x0,5 cm. Macroscopically the tumor was brownish in color. Histopathologically the tumor consisted of spindled and epitheloid cells. Immunohistochemically the tumor cells displayed positivity for S-100, HMB-45 and Melan-A. Findings were consistent with malignant melanoma.

DISCUSSION: Mucosal malignant melanomas have a poor prognosis despite chemotherapy and radiotherapy. Five-year survival for sinonasal melanoma is reported to be lower than 35%. Sinonasal melanomas show a high recurrence rate. The immunohistochemical markers showing high specificity for malignant melanoma such as S-100, HMB-45 and Melan-A are used in order to reach a correct diagnosis. In our case the tumor showed recurrence and multiple metastases 1 year after completion of radiotherapy. For this recurrent tumor, chemotherapy and radiotherapy have been planned.