Rare malignant melanotic nerve sheath tumors of the upper limb nerves: utility of high frequency ultrasonography in preoperative imaging Skeletal Radiology Springer Nature Link 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 Metastatic melanoma Tumoral Melanosis New England Journal of Medicine Frontiers Case report: Exceptional disease progression in a 70 year old patient: generalized melanosis and melanuria in the course of metastatic melanoma a case study