H&E
Microscopy: 1. to 3. Biopsies are from one intraoperative lesion and are described together. There is a pleomorphic neoplasm infiltrating the leptomeningeal space and extending into the cortex along Virchow-Robin space (also seen in specimens 2 and focally in specimen 3). The cells show nuclear pleomorphism with eosinophilic nucleoli and cytoplasmic melanin, and form sheet-like nodules with brain invasion. No necrosis is present and mitotic figures are not seen (0/10 HPF). The neoplastic cells express SOX10 and HMB45 (majority of cells). Ki67 proliferation index is estimated at 5%. The neoplasm shows pleomorphic melanocytes with leptomeningeal spread and brain invasion. The features are of leptomeningeal melanomatosis.
Supplementary report: c-Kit staining is positive.
Summary: 1.-3. Cortex, left frontal lobe; Parenchyma, left frontal lobe; Deep lesional tissue - Leptomeningeal melanomatosis, please see description.
