Diagnosis and therapy of sinonasal mucosal melanoma

Sinonasal mucosal melanoma (SNMM) is a rare and aggressive disease representing only 4% of all sinonasal malignancies and 1.4% of all melanomas. With an incidence of approximately 0.2 to 2 cases per million, the disease represents a very rare cancer type. As a result, there is a lack of data and most of the evidence for this highly aggressive disease is based on retrospective observations and analyses. The standard of care is radical tumor resection followed by an adjuvant radiotherapy. Nevertheless, the rate of local recurrence is high, up to 50%. In addition, the majority of patients (up to 70%) develop distant metastases during the course of their disease. Both contribute to the extremely poor prognosis of the disease. Mucosal melanomas (SM) and cutaneous melanomas (CM) behave differently with respect to biology, clinic presentation and prognosis. Compared to CM, survival rates are significantly lower for SM. The 5-year survival rate is around 25% in SNMM but 39-97% in cutaneous melanoma. Similar to CM, immune checkpoint inhibitors achieve promising results in SM. However, response rates are lower in SM compared to CM. The goal of this CME article is to provide an overview on biology, diagnosis, therapy, and prognosis of SNMM.