Malignant melanotic nerve sheath tumors in the spinal canal of psammomatous and non psammomatous type: Two case reports Interosseous Malignant Melanotic Nerve Sheath Tumor of the Sacrum Treated With an Innovative Reconstruction Technique Cureus Psammomatous melanotic schwannoma a rare neck lump The Annals of The Royal College of Surgeons of England Psammomatous melanotic schwannoma a rare neck lump The Annals of The Royal College of Surgeons of England