Sinonasal mucosal melanoma

Case contributed by Luis Fernando Avalos Quiroz

Presentation

Headache, epistaxis, rhinorrhea.

Patient Data

Age: 50 years
Gender: Female
CT

Soft tissue lesion inside the sphenoid and ethmoid sinus extends into the left maxillary sinus with a permeative pattern at this level, and it also extends into the left nasal fossa and left frontal sinus with partially defined margins and heterogeneous enhancement after intravenous contrast application . This lesion erodes the maxillary bones, medial wall of the left orbit, left lesser wing of the sphenoid and sella turcica. Involves the extraconal space of the left orbit and causes thickening of the medial rectus muscle.

Pathology

Histopathology Report

MRI

The expansive lesion appears heterogeneous, predominantly isointense to gray matter in T1 and FLAIR, and predominantly hyperintense in T2, with heterogeneous enhancement after
intravenous contrast application.

Case Discussion

The most likely origin of extracutaneous melanomas is from melanocytes present in the mucosa, which have migrated as neuroectodermal derivatives in epithelia of ectodermal origin of the upper respiratory and digestive tract. This would explain the low frequency of extracutaneous melanomas in sites lined by epithelia of endodermal origin such as the nasopharynx, larynx, tracheobronchial tree and esophagus.

Extracutaneous melanomas are neoplasms of adults and old people, most of the patients are between 50 and 70 years, almost two decades after the age of presentation of cutaneous melanomas.

Most extracutaneous melanomas arise in the nose and paranasal sinuses, followed by those located in the oral cavity or pharynx, there are very rare cases located in the larynx.
Patients with extracutaneous melanoma often present with symptoms related to the affected area, the majority being located in the nose, presenting nasal obstruction, epistaxis or rhinorrhea.

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