Exceptional examples have been reported from children and in other sites. These are thought to be of neural origin, but this interpretation is not conclusive. Few cases have been reported in the dermatologic literature.
Local recurrence is common.
Atypical as well as malignant variants have been described ref2 . An incompletely ossified fibrous rim that may or may not be continuous surrounds a central cellular area in most cases. The round tumor cells of medium size are relatively uniform in most areas, but spindle cell differentiation can be present. The tumor cells are often found in nests or clusters that are incompletely separated by delicate connective tissue. The clusters of cells can also be separated by a hyalinized fibrous matrix.