Malignant melanotic nerve sheath tumor with PRKAR1A, KMT2C and GNAQ mutations This is a very rare case of metastatic oral mucosal melanoma to the colon with an unusual presentation mimicking melanosis coli. The colonoscopy findings show no mass effect but multiple hyperpigmented lesions Malignant melanotic nerve sheath tumor Radiology Reference Article Radiopaedia.org Intracranial metastatic melanoma Radiology Reference Article Radiopaedia.org Diffuse Melanosis Cutis Under Immuno and Targeted Therapy Cussigh 2025 JEADV Clinical Practice Wiley Online Library