Keep Your Eye On the Ball (slideshow)

In August 2015, the patient complained that a firm area developed along the left side of his nose. MRI showed a new soft tissue mass along the left lateral nose and anterior to the left maxillary sinus, tracking posteriorly along the inferior orbital groove towards the left foramen rotundum and left cavernous sinus. There was progressive enhancement of the proximal left fifth and sixth cranial nerves. Transnasal biopsy demonstrated high-grade spindle cell neoplasm, positive for SOX-10, S-100 immunostains and rare tumors cells were Melan-A positive, consistent with desmoplastic melanoma (DM). DM, a spindle cell neoplasm, is a rare cause (less than 4% of cases) of cutaneous melanomas. DM most commonly presents as a painless non-pigmented plaque of the head or neck (1) and is most commonly positive for S-100 and rarely HMB-45 and Melan-A (2,3). In the literature, there are only seven reported cases of perineural invasion of the intracranial trigeminal nerve secondary to DM (3). Treatment with immunotherapy and radiation has been described (3,4). The patient was treated with Pembrolizumab, but the mass grew and he was switched to hypofractionated radiation therapy and ipilimumab/nivolumab in November 2015. MRI in July 2016 showed decreased enhancement and reduction in tumor size.