Generalized eruptive histiocytoma: a pediatric case.

Generalized eruptive histiocytoma (GEH) is a rare, benign, papular, self-healing histiocytosis characterized by recurrent crops of small, firm, tan to reddish papules that appear in a symmetrical fashion on the face, trunk and arms, affecting mainly adults. Approximately 31 cases have been described, of which 8 were in children. A new concept unifying the confusing potpourri of non-Langerhans cell histiocytosis has recently been described in which GEH has been considered to represent an early undifferentiated stage of various histiocytic disorders. We describe a 9-year-old boy who had all the features of GEH and emphasize the importance of clinical, histologic, immunohistochemical, and ultrastructural examination in the diagnosis of histiocytic disorders. On the basis of the increasing numbers of similar reported cases showing overlap in clinical and histologic features and in accordance with the new unifying concept of non-Langerhans cell histiocytosis, we presume that this group of disorders may represent a continuous spectrum of a single disease rather than a collection of separate disorders.