Abstract
INTRODUCTION: PSCM is exceedingly rare, comprising 1% of all melanomas. Unlike their cutaneous counterparts; the origin and clinical characteristics of these malignancies is poorly characterized. Mutations in GNAQ have been implicated in non-cutaneous melanocytic tumors. We present a case of PSCM and review the literature, with a focus on intramedullary PSCMs. CASE REPORT: A 64-year-old woman presented with patchy dysesthesias in the right leg from L1-S3 followed by weakness in the left lower extremity. Spinal MRI showed a large intramedullary mass at T9-T10. Biopsy confirmed PSCM. Clinical examination and whole-body PET were unremarkable for systemic malignancy. GNAQ mutation analysis pending. METHODS: The patient's clinical, radiographic, and pathologic evaluation led to a detailed exploration of the topic, including a review of the case literature and their references. Cases that met Hayward's criteria and were intramedullary, from the first report in 1906 to the present, were included. REVIEW: 34 cases were consistent with PSCM. 21 (63%) were female. The median age was 62. Symptoms were progressive over months. The median duration of symptoms prior to presentation was 12 months. Survival from the time of presentation varied greatly from <1 month to 13 years, with a median of 12 months. The anatomic distribution was predominantly thoracic (25, 74%), with the remainder of lesions in the cervical spine (9, 26%). A consistent pattern of imaging is evident; almost all tumors demonstrated hyperintensity on T1 weighted imaging. T2 imaging demonstrated more heterogeneous characteristics. CONCLUSION: Presentation of this disease is insidious in nature and presents with months of progressive neurologic deficits. Tumors are typically located in thoracic spine with characteristic imaging findings. GNAQ oncogene testing is pending and may indicate a distinct underlying biology to PSCM compared to cutaneous melanoma. Awareness may encourage surgical intervention, which is often delayed given the high risk of operation.