Solitary congenital Langerhans cell histiocytoma: A pattern of benign, spontaneous regression in patients with single lesion disease.

Langerhans cell histiocytosis (LCH) is the neoplastic proliferation of dendritic langerin-positive histiocytes manifesting as either single system unifocal, single system multifocal, or multisystem disease. The designation Hashimoto-Pritzker, or self-healing LCH, has fallen out of favor since it is impossible to predict at time of diagnosis whether the disease is truly self-remitting or capable of spreading to other organ systems. We review the English literature on solitary congenital Langerhans cell histiocytoma, draw novel conclusions from the data provided by 81 cases in the literature, and illustrate a typical presentation of the diagnosis with a previously unreported patient. Each of the patients diagnosed with solitary congenital histiocytoma experienced spontaneous resolution and had no signs of systemic disease at latest follow-up. Furthermore, we offer an analysis of the histopathological findings available from the 81 cases and our patient. Based on our study observations, we propose solitary congenital Langerhans cell histiocytoma may portend a good prognosis and represent a distinct entity. However, until further confirmation with prospective studies, we recommend clinicians continue conducting appropriate workup to rule out systemic involvement.