CHSU Discovery

Abstract:

Introduction/Background: Malignant Mucosal melanoma (MMM) arising from melanocytes in the mucosal linings of the body, is the least common and most aggressive form of melanoma. The Pathogenesis of mucosal melanoma is not well known compared to cutaneous melanomas. The poor prognosis of MMM is due to a variety of factors, including delayed diagnosis, lack of defined risk factors, and greater tumor mutational burden. This case report aims to describe the clinical, histopathological, and immunohistochemical features of a case of mucosal melanoma while contrasting it with other types of melanomas. 

Case: An 85-year-old Hispanic man presented with a two-week history of right-sided facial paresthesia, ophthalmoplegia with tearing, and odontalgia. Examination revealed a bulging mass within the right maxillary sinus. A head CT scan showed complete blockage of the right maxillary sinus with erosion of the surrounding bone, including the orbital floor. Biopsy confirmed the mass to be malignant, and a PET scan revealed metastasis to the lungs, liver, and bones. The patient was diagnosed with malignant mucosal melanoma of the right maxillary sinus. 
He received four cycles of immunotherapy with ipilimumab and nivolumab, and radiation therapy to the primary tumor in the right maxillary sinus. A follow-up PET scan showed marked improvement with a significant decrease in tumor size. 

Results and Conclusion: This case report provides insight into a rare presentation of MMM. Further investigation into the pathophysiology of MMM should be conducted to improve diagnostic approaches, early detection, tailored therapy and consequently, its outcome.