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Query: UMLS:C0019621 (Langerhans cell histiocytosis)
 3,250 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Histiocytosis X and mastocytosis are proliferative processes that may have similar cutaneous manifestations. However, a positive Darier's sign (urtication on stroking of the lesion) is thought to reliably distinguish between these two diseases. We recently studied a 13-year-old girl with a 2-year history of extensive skin lesions and a positive Darier's sign. Routine histopathologic studies revealed a polymorphous cutaneous infiltrate composed of histiocytes, mast cells, eosinophils, and lymphoid cells. Electron microscopic studies demonstrated Langerhans granules in some of the histiocytes, and immunologic studies of frozen tissue showed that a significant subpopulation of the histiocytes marked as Langerhans cells. Giemsa staining of specimens from eight other cases of cutaneous histiocytosis X from our files revealed mast cells in all of the lesions, although none showed the abundance of mast cells present in the case with urtication. Our studies emphasize the often polymorphous nature of the cell population in cutaneous histiocytosis X and demonstrate that confusing clinical findings can result when the mast cell population in histiocytosis X produces urtication.
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PMID:Urticating histiocytosis: a mast cell-rich variant of histiocytosis X. 242 66

We recently encountered a 2-year-old boy with slightly infiltrative brown papules on the face, trunk, and extremities. Stroking of one of the papules produced an urticarial wheal (positive Darier's sign). Histopathologic tests revealed a dense infiltration of mast cells containing numerous granules and showing metachromasia under Toluidine blue staining. Immunohistochemical tests revealed that these cells were positive for CD68 and for c-kit. In addition, dermal dendritic cells that were positive for S100 and CD1a immunostaining were intermingled with the mast cells. We confirmed through electron microscopy that the dermal dendritic cells that were observed adjacent to the infiltration of mast cells had Birbeck granules in their cytoplasm, namely Langerhans cells. However, because of the greater numbers of mast cells than Langerhans cells, and because of the absence of both monomorphic LC proliferation and systemic symptoms of Langerhans cell histiocytosis, the present case favors a diagnosis of cutaneous mastocytosis in a child with Langerhans cell infiltration.
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PMID:A case of cutaneous mastocytosis in a child with prominent Langerhans cell infiltration. 2073

Scabies is a common parasitic human infection in infants and children. However, diagnostic pitfalls are frequent in infants, in whom the clinical presentation is usually atypical and different from that in adults. In nodular scabies, lesions may be clinically or histologically misdiagnosed as Langerhans cell histiocytosis, insect bite reaction, non-Langerhans cell histiocytosis, lymphoma, or urticaria pigmentosa. We report two misleading cases of young infants (10- and 12-month-old infants) who presented with pruritic brown-red lesions on their trunks and showing a positive Darier's sign, suggestive of urticaria pigmentosa.
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PMID:Scabies mimicking mastocytosis in two infants. 2438 36