Primary leptomeningeal melanoma in an adolescent: Case report and review of the literature

Abstract

A previously healthy 16-year-old male patient came to the emergency department with a six-week history of left posterior hip pain following a head-on ATV collision. After failing conservative therapy, he was found to have weakness and atrophy of the left lower extremity on exam. MRI demonstrated an epidural mass that was hyperintense on T1 and hypointense on T2. Biopsy of the mass revealed a melanocytic lesion; further lesions were identified in the lungs, which biopsy proved to be malignant melanoma. Dermoscopy of the entire body, anoscopy, and retinal exam were negative for melanoma; a whole-body PET scan did not reveal any further lesions or evidence of a primary lesion. Given the lack of a primary lesion, this was thought to be a primary leptomeningeal melanoma. Primary melanomatous tumors of the spine are rare entities, with fewer than 40 cases described in the literature. This case was unique due to the patient's very young age and the presence of metastases on presentation.