Temporal bone mucosal melanoma masquerading as otomastoiditis

Background: Temporal bone mucosal melanoma (MM) is exceedingly rare and presents with nonspecific symptoms with an insidious progression. For these reasons, patients with temporal bone MM may experience delays in diagnosis. Here, we present a case of temporal bone MM initially masquerading as chronic otomastoiditis. Case presentation: A 68-year-old male veteran with history of lymphoma, basal cell carcinoma, chronic hepatitis B, and significant smoking history without any family history of melanoma presented to the ED with ear pain and epistaxis. The patient returned to the same ED 4 more times before being seen by our institution's otolaryngology department. Here, the patient reported total right-sided hearing loss and a new right-sided CNV3 paresthesia. On microscopy, a violaceous mass was noted behind the tympanic membrane, and confirmed on imaging. Transcanal biopsy confirmed the diagnosis of mucosal melanoma, and the patient was subsequently placed on ipilumumab/nivolumab therapy. After four months of immunotherapy and palliative care, the lesion was found to have enlarged, prompting additional radiotherapy. Conclusions: Temporal bone MM are often diagnosed later, with poorer survival outcomes when compared to their cutaneous equivalents. Surgical management is often limited by the presence of distant metastases and advanced locoregional involvement. Advancements in immunotherapeutic options are promising but limited to a few reports in the literature. Future research is required to better characterize the presentation, diagnosis, treatment, and outcomes of temporal bone MM.