Congenital agminated Spitz nevi: immunoreactivity with a melanoma-associated monoclonal antibody

Agminated, or grouped Spitz nevi are a curious expression of nevomelanocytic growth; and represent an uncommon manifestation of these nevi. We encountered an example of agminated Spitz nevi present at birth, which showed progression and rapid growth over months. All showed histologic Spitz nevus features. Avidin-biotin immunohistochemical techniques using anti S-100 protein, neuron-specific enolase (NSE), and melanoma-specific monoclonal antibody, HMB-45 labelled the nevi as follows: diffuse S-100 and NSE staining in most and HMB-45 positivity in sporadic cells deep in the dermis. HMB-45 reactivity occurred in both spindle cells and epithelioid forms.