Benign cephalic histiocytosis: a distinct entity or a part of a wide spectrum of histiocytic proliferative disorders of children? A histopathological study

When benign cephalic histiocytosis (BCH) was described for the first time in 1971, it was considered a nosologic entity due to its peculiar clinical presentation, but in the last few years its individuality has been questioned because of histopathological features overlapping with other non-X histiocytoses such as generalized eruptive histiocytosis (GEH). To solve this question, we examined with light microscopy using blinded technique 18 biopsy specimens obtained from 14 patients affected by BCH in comparison with 4 biopsies of GEH, 11 biopsies of papular xanthoma, and 25 biopsies of juvenile xanthogranuloma (JXG) of childhood. In the examined specimens, we identified three distinct patterns of proliferation of histiocytes we named "papillary dermal," "lichenoid," and "diffuse." With the exception of some peculiar histopathological features of BCH, observed only in the "papillary dermal pattern," a close histological relationship was observed among BCH, GEH, and JXG early nonxanthomatous stage. Our data suggest that BCH might be a localized form of GEH or an aborted phase of JXG.