Clinical Features, Dermoscopic Patterns, and Histological Diagnostic Model for Melanocytic Tumors of Uncertain Malignant Potential (MELTUMP).

Cutaneous melanocytic lesions with atypical histological features can be difficult to categorize as benign or malignant. In the diagnosis of melanocytic lesions, the melanocytic tumor of uncertain malignant potential (MELTUMP) category has been widely used. Although one may favor a benign or malignant interpretation, a definitive diagnosis is not always possible, and long term clinical follow-up remains the only true evidence of biological behavior. We report 14 cases of MELTUMP with expert second opinion. Clinical pictures were available in 8 cases; dermoscopy was available in 5 cases. Accurate guidelines are delineated in the formulation of the diagnosis. We think that the histological diagnosis should be accompanied by a note in which the pathologist describes the histological pattern that has generated diagnostic uncertainty. Since the MELTUMP term does not exclude the malignant nature of the lesion, all microstaging attributes for melanoma should be added. Moreover, superficial atypical melanocytic proliferation of uncertain significance (SAMPUS) and MELTUMP categories should be included in the WHO classification of melanocytic tumors of the skin. The role of sentinel lymph node biopsy in MELTUMP has not yet been established. Recent studies have looked at concurrent tumor deposits in lymph nodes of MELTUMP, mostly of atypical Spitzoid lesions, and shown that these lesions rarely progress to overt malignancy. In our study, sentinel node metastasis was found in only one case. The follow-up period of this case and of the others has shown that the clinical outcome of MELTUMP tends to be favorable.