Late-onset self-healing reticulohistiocytosis: pediatric case of Hashimoto-Pritzker type Langerhans cell histiocytosis.

An 8-year-old otherwise healthy girl presented with a 3-month history of multiple asymptomatic, reddish-brown papules over the face and upper limbs. Histopathological and immunohistochemical examinations demonstrated an infiltrate of mononuclear cells containing abundant histiocytic cells in the dermis, and microabscess-like accumulation of the histiocytic cells in the epidermis. The histiocytic cells were positive for antibodies against S-100 protein and CD1a, but negative for anti-CD68. Lag and anti-langerin monoclonal antibodies reacted more weakly with these histiocytic cells than with Langerhans cells in the surrounding epidermis. The skin lesions spontaneously regressed within the following 3 months, and neither systemic involvement nor local recurrence was observed during the next 10 months. This case should be categorized as congenital self-healing reticulohistiocytosis (Hashimoto-Pritzker), although the onset was not early in life.