PMC4900124_01
16-year-old male with primary leptomeningeal melanoma. A T1-weighted image of the lumbar spine shows a hyperintense epidural mass.
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T1-weighted images (Fig. 1) and hypointense on T2-weighted images (Fig. 2). The lesion had significant mass effect on the left sacral nerve roots, with hemorrhage extending into the S1-S2 and S2-S3 neuroforamina and accompanying severe central spinal stenosis.
16-year-old male with primary leptomeningeal melanoma. A slide from the resection of the epidural lesion at the base of the spine shows a largely necrotic tumor. The better preserved cells are dyscohesive, with round pyknotic nuclei and moderately abundant eosinophilic cytoplasm. Mitoses are not seen, and the MIB-1 rate (a measure of the cellular reproductive rate) was very low. Abundant dark brown patches suggest a melanocytic neoplasm.
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In order to rule out metastatic disease, two pulmonary nodule biopsies were obtained and interpreted as malignant melanoma; the lesions appeared black when removed (Figure 3, Figure 4).
16-year-old male with primary leptomeningeal melanoma. Immunohistochemistry for the melanocyte-specific marker Melan-A shows the characteristic cytoplasmic staining, confirming the diagnosis of a melanocytic neoplasm.
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In order to rule out metastatic disease, two pulmonary nodule biopsies were obtained and interpreted as malignant melanoma; the lesions appeared black when removed (Figure 3, Figure 4).