Malignant melanoma presenting as nasal obstruction. Mucosal melanomas arising in the nasal cavity are rare tumors comprising less than 1 percent of all melanomas. Often, the common clinical symptom is nasal obstruction. Grossly, they may or may not be pigmented and frequently attain large sizes. Histologic diagnosis of these tumors may be difficult, requiring immunohistochemical or electron microscopic confirmation. Aggressive surgical management is the treatment of choice in clinical stage I disease. Subsequent surveillance for recurrence is mandatory. Markers such as 5-S-cysteinyldopa may prove useful in staging, prognosticating, and postoperative surveillance for early recurrence, but their exact role has yet to be delineated. Ultimate prognosis is poor. 