Spitz nevus is named after Dr. Sophie Spitz, who in 1948 reported a case series of “melanomas of childhood.”
Nearly all of Spitz’s original series of 13 cases are now regarded as representing Spitz nevi, only one case having proved to be a melanoma resulting in metastasis and death.
Despite its benign nature, Spitz nevus has also been described under the headings of “juvenile melanoma,” “benign juvenile melanoma,” and “prepubertal melanoma.” These terms are potentially confusing as Spitz nevus is benign, but as these synonyms imply, the differential diagnosis of Spitz nevus and spitzoid melanoma can be among the most challenging in dermatopathology. Elucidation of many of the molecular genetic underpinnings of Spitz nevi over the past several years have revealed a variety of mutations that support a biologic spectrum of Spitz tumors ranging from Spitz nevi to spitzoid melanoma, with an intermediate group designated “atypical Spitz tumors” (AST) representing tumors partly transformed towards potential melanoma and reflected by ambiguous, intermediate, or indeterminate histopathologic appearances and intermediate malignant potential.
Spitz nevus may still be regarded as a clinically and histologically distinct variant of melanocytic nevus composed of spindled and/or epithelioid melanocytes (in the configuration of a benign tumor). Synonyms include Spitz’s nevus, Spitz tumor, and spindle and epithelioid cell nevus.
The spectrum of Spitz nevi includes junctional, compound (most common), and intradermal variants. Most desmoplastic Spitz nevi are intradermal or predominantly intradermal. Pigmented spindle cell nevus (Reed nevus) is regarded by most authorities as a clinically and histologically distinct variant of Spitz nevus.
Many other clinical and histologic variants have been described.
Spitz nevus has been characterized as relatively uncommon: it is estimated to account for only about 1% of surgically removed nevi.
Spitz nevus affects males and females, and the majority arise before the age 20 years.