Melanocytic tumors of uncertain malignant potential (MELTUMP) are melanocytic lesions in the dermis that cannot be classified by morphology as either benign naevi (moles) or malignant melanomas because the mass shows features of both.

Several lesion types may be classified as MELTUMPs: atypical Spitz naevi, dysplastic naevi, pigmented epithelioid melanocytoma, deep penetrating naevi, congenital neavi, cellular nodules in congenital naevi, possible naevoid melanomas, and cellular blue naevi.^[1][2]

A related category of melanocytic proliferation is superficial atypical melanocytic proliferations of uncertain significance (SAMPUS), which includes junctional melanocytic proliferations and proliferations in the epidermis and papillary dermis that are not accompanied by tumorigenic cell mitosis.^[1]