A rare case of CD1a-negative Langerhans cell histiocytosis of the central nervous system in a child

Abstract

Langerhans cell histiocytosis is a dendritic cell disorder with a wide spectrum of severity and presentations. Histopathology typically demonstrates a proliferation of Langerhans cells and a lymphohistiocytic inflammatory infiltrate with eosinophils. The diagnosis is supported by immunohistochemistry with the cell markers S100, CD1a, CD68, and Langerin [Blood, 126, 2015, 26 and N Engl J Med, 331, 1994, 154].

Keywords: Basal ganglia; CD1a; Langerhans cell histiocytosis; S100; dendritic cell disorder; diabetes insipidus.

Figure 1

S100 immunohistochemistry. Close examination reveals that the perivascular Langerin‐positive cells express S100 protein. Note that the background glioneuronal tissue is also S100 protein positive.

Figure 2

Histopathology of brain lesion. (A, B) Dendritic cell infiltration with mixed inflammation including histiocytes, lymphocytes, plasma cells, and rare eosinophils (H&E 200× and 400×). (C) Langerhans cells lack CD1a expression (200×). (D) Langerin immunohistochemistry demonstrates Langerhans cells predominantly involving the Virchow–Robin spaces (200×).