Background
Patients with the atypical mole syndrome have multiple dysplastic nevithat appear to be randomly distributed on certain preferred anatomical sitessuch as the upper back. These dysplastic nevi are thought to be acquired melanocyticnevi that begin appearing at puberty. To our knowledge, the presence of agminatedatypical (dysplastic) nevi has not been reported.
Observation
We describe a patient with the atypical mole syndrome who has more than100 melanocytic nevi, many of which are clinically atypical and one of whichproved to be a melanoma. Among his many melanocytic nevi is a cluster of approximately50 nevi that are distributed in an area measuring 5 × 3 cm. The histopathologicfeatures of these nevi are consistent with the diagnosis of "dysplastic nevus."
Conclusions
To our knowledge, agminated atypical (dysplastic) nevi have not beendescribed previously. The presence of agminated atypical (dysplastic) neviin a patient with the atypical mole syndrome can be theorized to arise becauseof loss of heterozygosity.