title: A case of cutaneous mastocytosis in a child with prominent Langerhans cell infiltration.
abstract: 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.
authors.affiliation: Department of Dermatology, Nihon University School of Medicine, Itabashi-ku, Tokyo, Japan.
authors.forename: Juniku
authors.initials: J
authors.lastname: Mitsuya
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Hara
authors.forename: Naozumi
authors.initials: N
authors.lastname: Fukuda
authors.forename: Tadashi
authors.initials: T
authors.lastname: Terui
mesh_terms: D015703:Antigens, CD / Q000378:metabolism; D018949:Antigens, CD1 / Q000378:metabolism; D015214:Antigens, Differentiation, Myelomonocytic / Q000378:metabolism; D002675:Child, Preschool; D003533:Cyproheptadine / Q000627:therapeutic use; D006634:Histamine H1 Antagonists / Q000627:therapeutic use; D006801:Humans; D007801:Langerhans Cells / Q000187:drug effects / Q000378:metabolism* / Q000473:pathology / Q000648:ultrastructure; D008297:Male; D008407:Mast Cells / Q000187:drug effects / Q000378:metabolism / Q000473:pathology; D034701:Mastocytosis, Cutaneous / Q000175:diagnosis* / Q000188:drug therapy / Q000378:metabolism* / Q000473:pathology; D019009:Proto-Oncogene Proteins c-kit / Q000378:metabolism; D009418:S100 Proteins / Q000378:metabolism; D016896:Treatment Outcome; D000097382:CD68 Molecule
chemical_list: D015703:Antigens, CD; D018949:Antigens, CD1; D015214:Antigens, Differentiation, Myelomonocytic; D003533:Cyproheptadine; D006634:Histamine H1 Antagonists; D019009:Proto-Oncogene Proteins c-kit; D009418:S100 Proteins; C419393:CD1a antigen; C067980:CD68 antigen, human; D000097382:CD68 Molecule