OBJECTIVE: To report a case of primary melanoma of the maxillary sinus and to raise awareness of this diagnosis in patients with inexpressive nasal symptoms. CASE REPORT: A 46-year-old man visited the otolaryngology department complaining of pain in the right hemifacial region associated with periorbital edema for the past 6 months. The ear, nose, and throat (ENT) physical examination was normal. A computed tomography scan revealed a large mass in the right maxillary sinus with bone erosion. Magnetic resonance imaging showed a heterogeneous, expansive formation in the right maxillary sinus with bone erosion and extension into the adjacent soft tissues and primary neoplastic involvement of the maxillary sinus was suspected. A maxillary sinusotomy was performed using the Caldwell-Luc approach, and the results of the pathological and immunohistochemical examinations were compatible with a diagnosis of melanoma. The patient was referred to the oncology and head and neck surgery departments. CONCLUSION: Primary sinonasal melanoma affects 0.15 individuals per 100,000 individuals. The most common symptoms are nasal obstruction and epistaxis. It presents as a polypoid, intra-nasal mass, blackish or yellowish in color, and the most frequent tumor sites are the nasal septum and the inferior and middle turbinates. This condition, although rare, should be included in the differential diagnosis of sinonasal tumors, even in patients who present atypical symptoms.