Malignant melanotic nerve sheath tumors in the spinal canal of psammomatous and non psammomatous type: Two case reports A Rare Case of Epithelioid Malignant Peripheral Nerve Sheath Tumor Mimicking Malignant Melanoma Cureus Pathology Outlines Malignant melanotic nerve sheath tumor Malignant peripheral nerve sheath tumour treated with Oncothermia Interosseous Malignant Melanotic Nerve Sheath Tumor of the Sacrum Treated With an Innovative Reconstruction Technique Cureus