Langerhans Cell Histiocytosis

Langerhans cell histiocytosis is characterized by a proliferation of CD1a, langerin (CD207), S100 positive cells presenting as a localized, multifocal, or disseminated disease. Multisystem disease portends a more aggressive clinical course compared to localized disease. The Birbeck granule is seen on electron microscopic examination. The implicated cell typically shows a folded grooved nucleus likened to a coffee bean and is frequently seen in association with eosinophils and scattered lymphocytes.

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Slide 1: 6 month-old girl with a recalcitrant diaper rash consisting of few pink papulonodules. The biopsy shows a band-like infiltrate of histiocytoid appearing cells. The infiltrate is focally permeative of the epidermis. The actual biopsy is centered around a follicle which is infiltrated by neutrophils with an overlying neutrophil imbued scale crust.

Slide 2: In examining the cells under higher magnification they are intermediate in size.

Slide 3: The cells do exhibit a cytomorphology typical of a Langerhans cell. These cells have eccentrically disposed nuclei with fairly abundant eosinophilic cytoplasms. The nuclei range in quality from being round, oval to frankly reniform.

Slide 4: The abnormal cells are diffusely positive for CD163.

Slide 5: Langerin is strongly positive as well.