Clinical and histologic features of level 2 cutaneous malignant melanoma associated with metastasis.
BACKGROUND
Metastatic melanoma developing in patients with a level 2 primary cutaneous malignant melanoma (CMM) is rare but has been reported in studies with follow-up periods ranging up to 15 years. The objective of this study was to investigate level 2 CMM associated with metastasis in a population-based retrospective study.


METHODS
In this retrospective population-based study, all level 2 CMMs associated with metastases were identified in Western Australia during 1982-1989 and were followed up to the end of 1996.


RESULTS
Pathology reports of 2834 patients were examined. Of these, 1716 had a CMM of maximum tumor thickness 1 mm or less recorded on the pathology report. Of these, 67 had a metastatic melanoma reported on follow-up. Histologic review of these 67 cases under blind conditions identified 5 cases with a level 2 primary CMM followed by metastasis without another primary CMM. All these level 2 CMM showed established regression. Eight other patients were identified with a level 2 CMM, metastatic melanoma, and another primary CMM of at least level 3 invasion. These subsequent primaries occurred before the metastasis had been reported.


CONCLUSIONS
These findings suggest that metastasis from level 2 CMM without regression is very rare, if it occurs at all.
Taran
J M
JM
Department of Pathology, University of Western Australia, Queen Elizabeth II Medical Centre, Nedlands, Western Australia. pheenan@cyllene.uwa.edu.au
Heenan
P J
PJ
D006801:Humans; D008545:Melanoma / Q000473:pathology / Q000556:secondary*; D009361:Neoplasm Invasiveness; D009362:Neoplasm Metastasis / Q000175:diagnosis; D009367:Neoplasm Staging; D011379:Prognosis; D012189:Retrospective Studies