title: S100-Negative, CD1a-Positive Cutaneous Histiocytosis in a Patient with S100-Positive, CD1a-Positive Pulmonary Histiocytosis.
abstract: In the diagnostic approach to histiocytic proliferations, immunohistochemistry may be a source of both confusion and clarification. We present a case of a 60-year-old man with a generalized pruritic eruption that demonstrated positive staining for CD1a, but negative staining for langerin and S100 protein. This immunophenotype is neither representative nor characteristic of any recognized dendritic cell tumor but has been previously described in 3 cases of skin-limited histiocytosis. However, our patient also demonstrated pulmonary histiocytic infiltrates that were positive for both CD1a and S100 proteins. This differing expression of S100 protein witnessed in 2 separate organ systems affords us insight into the pathophysiology of these histiocytic proliferations.
authors.affiliation: *Department of Dermatology, Texas Tech University Health Sciences Center, Lubbock, TX; †Department of Dermatopathology, the University of Oklahoma Health sciences Center, Oklahoma, OK; ‡Department of Dermatology, The University of Oklahoma Health Sciences Center, Oklahoma, OK; and §Department of Pulmonology and Critical Care Medicine, Tulsa, OK.
authors.forename: Lisa
authors.initials: L
authors.lastname: Mask-Bull
authors.forename: Neil A
authors.initials: NA
authors.lastname: Crowson
authors.forename: Andrew
authors.initials: A
authors.lastname: John
authors.forename: Neal A
authors.initials: NA
authors.lastname: Mask
mesh_terms: D015703:Antigens, CD / Q000032:analysis; D018949:Antigens, CD1 / Q000032:analysis; D015214:Antigens, Differentiation, Myelomonocytic / Q000032:analysis; D006646:Histiocytosis, Langerhans-Cell / Q000378:metabolism* / Q000473:pathology*; D015616:Histiocytosis, Non-Langerhans-Cell / Q000378:metabolism*; D006801:Humans; D037181:Lectins, C-Type / Q000032:analysis; D008297:Male; D037241:Mannose-Binding Lectins / Q000032:analysis; D008875:Middle Aged; D009418:S100 Proteins / Q000032:analysis; D012871:Skin Diseases / Q000378:metabolism* / Q000473:pathology*; D000097382:CD68 Molecule
chemical_list: D015703:Antigens, CD; D018949:Antigens, CD1; D015214:Antigens, Differentiation, Myelomonocytic; D037181:Lectins, C-Type; D037241:Mannose-Binding Lectins; D009418:S100 Proteins; C419393:CD1a antigen; C121916:CD207 protein, human; C067980:CD68 antigen, human; D000097382:CD68 Molecule