Melanocytic tumors of uncertain malignant potential: results of a tutorial held at the XXIX Symposium of the International Society of Dermatopathology in Graz, October 2008.
Several reports demonstrated the difficulties and lack of agreement in the histopathologic diagnosis of particular melanocytic tumors (atypical Spitz tumors, atypical blue nevi, deep penetrating nevi). These lesions are often referred to as "melanocytic tumors of uncertain malignant potential" (MELTUMP). We studied a large number of such tumors to find out whether repeatable histopathologic criteria for distinction of benign from malignant cases exist. Fifty-seven cases of MELTUMP were classified within 3 groups according to behavior as follows: (a) favorable (no evidence of metastatic disease after a follow-up of > or = 5 y), (b) unfavorable (tumor-related death and/or large metastatic deposits in the lymph nodes and/or visceral metastases), (c) borderline (small nodal deposits of tumor cells < or = 0.2 mm). There were no significant differences in tumor thickness and presence or absence of ulceration between the different groups. The only 3 histopathologic criteria that were statistically different between the groups of favorable and unfavorable cases were presence of mitoses, mitoses near the base, and an inflammatory reaction, all of them found more frequently in cases with unfavorable behavior. The major outcome of this study of a series of "MELTUMPs" suggests as a preliminary observation that these lesions as a group exist and that they may be biologically different from conventional melanoma and benign melanocytic nevi. The terminology remains highly controversial, reflecting the uncertainty in classification and interpretation of these atypical melanocytic tumors.
Cerroni
Lorenzo
L
Department of Dermatology, Medical University of Graz, A-8036 Graz, Austria. lorenzo.cerroni@medunigraz.at
Barnhill
Raymond
R
Elder
David
D
Gottlieb
Geoffrey
G
Heenan
Peter
P
Kutzner
Heinz
H
LeBoit
Philip E
PE
Mihm
Martin
M
Rosai
Juan
J
Kerl
Helmut
H
D000293:Adolescent; D000328:Adult; D000368:Aged; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007223:Infant; D007249:Inflammation / Q000473:pathology; D053208:Kaplan-Meier Estimate; D008207:Lymphatic Metastasis; D008297:Male; D008544:Melanocytes / Q000473:pathology*; D008875:Middle Aged; D008938:Mitosis; D009361:Neoplasm Invasiveness; D009367:Neoplasm Staging; D018329:Nevus, Blue / Q000145:classification / Q000401:mortality / Q000473:pathology* / Q000556:secondary / Q000628:therapy; D018332:Nevus, Epithelioid and Spindle Cell / Q000145:classification / Q000401:mortality / Q000473:pathology* / Q000628:therapy; D012878:Skin Neoplasms / Q000145:classification / Q000401:mortality / Q000473:pathology* / Q000556:secondary / Q000628:therapy; D009626:Terminology as Topic; D013997:Time Factors; D016896:Treatment Outcome; D055815:Young Adult