Abstract | April 5, 2022
A challenging case of Metastatic Mucosal Melanoma
Learning Objectives
- IL-6 is produced by malignant melanoma. CRP is a surrogate marker for IL-6, hence CRP is used to discriminate from non-progressive metastatic melanoma disease;
- Ipilimumab is a monoclonal antibody which works by activating the immune system by targeting CTLA-4, a protein receptor that downregulates the immune system;
- Nivolumab is a targeted therapy against human programmed death receptor-1 (PD-1).
Introduction: Mucosal melanoma is a rare and extremely aggressive malignancy, distinct from other melanomas. Melanocytes, though abundant in the skin, can also be found in the mucous membrane. By virtue of the cells being from different sites, their epidemiologic, genetic and physiologic behaviours are different, and has an implication in the prognosis and management. Here we present a patient with metastatic mucosal melanoma, intending to highlight the aggressive nature of the disease.
Case Report: A 63-year-old gentleman with recently diagnosed mucosal melanoma presented to our facility. He initially had a nasal polyp, which on resection confirmed mucosal melanoma. He underwent surgical resection of the mass, maxillary sinus exploration and right hemi-palate excision. There were no targetable mutations on next generation sequencing. He was MSI stable and TMB 3 mutations per megabase. There were several alterations in pro-proliferative genes including MYC, NRAS, PIK3CA, VEGF.
Unfortunately, he had recurrence within few weeks, in the form of cheek nodule. Oncologic evaluation showed multiple pulmonary nodule consistent with metastasis. Combination of ipilimumab and nivolumab was started in an aggressive effort to control his quickly progressing metastatic mucosal melanoma.
One week following initiation of immunotherapy, he presented to our facility with complaints of dyspnea. On presentation, he was hemodynamically stable, but hypoxic with saturation in 80s, requiring nasal canula oxygen. Investigations showed leukocytosis at 20.4x 103/µL. Chest X ray showed multifocal scattered patchy interstitial alveolar opacities. COVID-19 was negative.
Working diagnosis: Differentials for patient’s dyspnea included Pneumonia, Pneumonitis or Pulmonary metastasis.
Management: Patient was started on broad spectrum intravenous antibiotics with Vancomycin and Piperacillin Tazobactum. He was also initiated on high-dose steroids 1 mg/kg of prednisone for management of pneumonitis. CRP, which is a surrogate marker for IL-6, was elevated at 26.9 (ref range: 0-0.99). Following recommendations from infectious disease team, azithromycin was added for atypical coverage and micafungin added due to immunocompromised state of patient. With only modest improvement, patient was discharged on his insistence, on oral antibiotics, much against the medical team’s recommendations. He was advised close follow up with the oncology team soon after. He was hypoxic and oxygen dependent on discharge.
