Sinonasal Mucosal Melanoma Response to Immunotherapy: Surgical Resection of Necrosis

 

Introduction: Sinonasal mucosal melanoma carries a very poor prognosis with limited treatment options for late-stage disease. Immunotherapy has emerged as a promising treatment modality in patients with mucosal and cutaneous melanomas, and may provide benefit in patients with advanced disease.

Methods: Retrospective case review.

Results: A 58-year-old male diagnosed with a bulky sinonasal mucosal melanoma presented to our tertiary care academic medical center. MRI scan demonstrated a 3.7 cm enhancing mass obliterating the left maxillary sinus with infiltration of the ipsilateral ethmoid air cells and extraconal orbit. Imaging findings were suggestive of retrograde perineural spread across the left infraorbital nerve resulting in expansion of the infraorbital canal from the left pterygomaxillary fissure through the subcutaneous premaxillary soft tissues adjacent to the infraorbital foramen. Images were also concerning for retrograde perineural spread in the left foramen rotundum and anterior aspect of the left cavernous sinus. Operative biopsies confirmed sinonasal mucosal melanoma. Genetic testing was negative for the BRAF V600E, V600K, and KIT mutations. The patient underwent first line therapy with combination ipilimumab and nivolumab for two doses followed by definitive radiation. He then received single agent nivolumab bi-monthly for an additional ten weeks. Imaging revealed an excellent response to treatment. He was taken to the operating room for surgical resection of disease to assess if viable tumor remained. Final pathology revealed necrotic neoplasm and abundant pigment-laden macrophages. There was no viable neoplasm identified on final pathology. Serial imaging continues to show no evidence of new tumor growth. The patient currently receives monthly nivolumab infusions. [Fig. 1] provides representative radiologic findings throughout disease course.

Conclusion: This case highlights the potential of immunotherapy as a promising treatment modality in patients with sinonasal mucosal melanoma. The biopsy-confirmed bulky sinonasal mucosal melanoma showed complete response to immunotherapy as evidenced by surgical resection showing only necrotic tumor without any residual viable neoplasm.

Publication History

Article published online:
15 February 2022

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