Langerhans Cell Histiocytosis

Question 1

What are Langerhans cells?

Answer 1

Specialized dendritic cells found predominantly ion the skin derived from BM monocytes, present antigen to naive T cells

Question 2

What is Langerhans cell histiocytosis? Histo findings?

Answer 2

Neoplastic proliferation of LH cells; Birbeck (tennis racket) granules seen on EM, cells are CD1a+ and S100+ by immunohistochemistry

Question 3

What is Letterer-Siwe Disease? Classic presentation? Complications?

Answer 3

Malig prolif of Langerhans cells; Skin rash and cystic skeletal defects in an infant (< 2yo); Multiple organs, rapidly fatal

Question 4

What is Eosinophilic Granuloma? Presentation? Biopsy?

Answer 4

Benign proliferation of Langerhans cells in bone; Pathologic fracture in adolescent, skin NOT involved; Biopsy: LH cells with mixed inflammatory cells + MANY eosinophils

Question 5

What is Hand-Schueller-Christian Disease? Classic Presentation?

Answer 5

Malignant proliferation of Langerhans cells; Scalp rash, lytic skull defects, diabetes insipidus, exophthalmos in child

Question 6

Mnemonic to remember LH cell histiocytosis subtypes

Answer 6

Named after someone, normally malignant. If two names seen in children under 2 yo; If 3 names, seen in people older than 3