[Mucosal malignant melanoma of the nasal cavity and paranasal sinuses: two case reports of nonspecific clinical features].

Mucosal malignant melanoma of the nasal cavity and paranasal sinuses are rare. Because symptoms and radiological examinations of this disease are generally nonspecific, the diagnosis is often difficult. Diagnosis can be confirmed by the immunohistochemical profile of staining with HMB-45 and S-100. This study deals with two cases of nonspecific clinical features. The factors of misdiagnosis were discussed and the lesson was summarized.