Malignant melanotic nerve sheath tumors in the spinal canal of psammomatous and non psammomatous type: Two case reports Since melanoma develops on the skin, it can often be seen without special tests. Regular skin self exams and professional skin checks by a dermatologist can help detect melanoma early, when Rare Forms of Melanoma and Melanocytic Tumors IntechOpen Rare Forms of Melanoma and Melanocytic Tumors IntechOpen Rare Forms of Melanoma and Melanocytic Tumors IntechOpen