Not to be Forgotten: Cutaneous Langerhans' Cell Histiocytosis in an Adult
Campanati and coworkers (p. 299–301) describe an interesting differential diagnostic case: an elderly patient who developed large, diffuse erythematous inflammatory plaques resembling psoriasis inversa, impetiginized eczema or intertrigo. A skin biopsy revealed a lymphohistiocytic infiltration consisting of histiocytes with large kidney-shaped nuclei and abundant pink cytoplasm. A diagnosis of Langerhans' cell histiocytosis (LCH) was made. LCH is best known in neonates and young children, since the vast majority of LHC patients are children under 10 years of age. LCH can range from limited involvement that spontaneously regresses to progressive multiorgan involvement. Letterer-Siwe disease (LSD) is the disseminated multisystemic form of LCH and often, the course of LSD is rapid and fatal. However, LCH is also found in adults of all ages, although less often. Most adult patients will survive LCH but in some cases, the disease may run a progressive course and can be life threatening. Why do the Langerhans' cells proliferate is not known, and since LCH is so rare, very little research has been directed into its cause and treatment.