title: Histiocytoid Sweet's Syndrome: A localized cutaneous proliferation of macrophages frequently associated with chronic myeloproliferative disease.
abstract: BACKGROUND
  Histiocytoid Sweet's syndrome was originally described as cutaneous lesions of Sweet's syndrome where the infiltrate is mostly composed of histiocytoid mononuclear cells. The putative cell has been interpreted as an immature neutrophil based on the intense expression of myeloperoxidase.
  
  
  METHODS
  To better understand the nature of the infiltrate and potential mechanisms leading to this distinct form of cutaneous inflammatory cell influx, thirteen cases of histiocytoid Sweet's syndrome, encountered in the routine and consult practice of one of the authors, were studied. The clinical features and microscopic findings are summarized.
  
  
  RESULTS
  The study comprised eight men and five women aged from 23 to 80. There was a significant association with underlying myeloproliferative disease. In particular, five patients had underlying myelodysplastic syndrome. One patient had unspecified chronic myeloproliferative disorder and another had AML. Two cases were triggered by drug therapy (Cox-2 inhibitors). One patient had familial Mediterranean fever. The eruption was asymptomatic and an aggressive clinical course was not observed in most cases. Skin biopsies were composed of striking angiocentric and intersititial mononuclear cell infiltrates, often accentuated in the deeper dermis and subcutaneous fat. There was marked leukocytoclasia. Neutrophils were sparce or absent. These cells were strongly positive for CD163 and either expressed CD16 or myeloperoxidase. Variable positivity for myeloid dendritic cell markers including CD11c, BDCA-3, TCL1 oncogene, MXA and CD123 was observed.
  
  
  CONCLUSIONS
  The histiocytoid cells of histiocytoid Sweet's syndrome define a novel subset of activated monocytes. This variant of Sweet's syndrome has a significant association with underlying myeloproliferative disease.
authors.affiliation: Department of Pathology, Laboratory Medicine, Weill Medical College of Cornell University, 1300 York Ave, Room F309, New York, NY 10065, USA.
authors.forename: Cynthia M
authors.initials: CM
authors.lastname: Magro
authors.affiliation: Department of Pathology, Laboratory Medicine, Weill Medical College of Cornell University, 1300 York Ave, Room F309, New York, NY 10065, USA.
authors.forename: Shabnam
authors.initials: S
authors.lastname: Momtahen
authors.affiliation: Department of Medicine, Georgetown University Hospital, Washington, DC 20007, USA.
authors.forename: Giang H
authors.initials: GH
authors.lastname: Nguyen
authors.affiliation: Department of Pathology, Laboratory Medicine, Weill Medical College of Cornell University, 1300 York Ave, Room F309, New York, NY 10065, USA.
authors.forename: Xuan
authors.initials: X
authors.lastname: Wang
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015703:Antigens, CD / Q000032:analysis; D015214:Antigens, Differentiation, Myelomonocytic / Q000032:analysis; D000954:Antigens, Surface / Q000032:analysis; D039521:CD11c Antigen; D003713:Dendritic Cells / Q000737:chemistry / Q000473:pathology; D005260:Female; D058851:GPI-Linked Proteins / Q000032:analysis; D006644:Histiocytes / Q000737:chemistry* / Q000473:pathology; D006801:Humans; D053650:Interleukin-3 Receptor alpha Subunit / Q000032:analysis; D015470:Leukemia, Myeloid, Acute / Q000150:complications; D007963:Leukocytes, Mononuclear; D008297:Male; D008875:Middle Aged; D009190:Myelodysplastic Syndromes / Q000150:complications*; D009196:Myeloproliferative Disorders / Q000150:complications*; D064547:Myxovirus Resistance Proteins / Q000032:analysis; D009504:Neutrophils; D009195:Peroxidase / Q000032:analysis; D010641:Phenotype; D011518:Proto-Oncogene Proteins / Q000032:analysis; D011956:Receptors, Cell Surface / Q000032:analysis; D017452:Receptors, IgG / Q000032:analysis; D016463:Sweet Syndrome / Q000150:complications* / Q000473:pathology*; D018180:Thrombomodulin; D055815:Young Adult; D000098902:CD163 Antigen
chemical_list: D015703:Antigens, CD; D015214:Antigens, Differentiation, Myelomonocytic; D000954:Antigens, Surface; D039521:CD11c Antigen; D000098902:CD163 Antigen; C428200:FCGR3B protein, human; D058851:GPI-Linked Proteins; D053650:Interleukin-3 Receptor alpha Subunit; C579071:MX1 protein, human; D064547:Myxovirus Resistance Proteins; D011518:Proto-Oncogene Proteins; D011956:Receptors, Cell Surface; D017452:Receptors, IgG; C090851:TCL1A protein, human; C546931:THBD protein, human; D018180:Thrombomodulin; D009195:Peroxidase
keywords: Sweet's syndrome; clonal cutaneous monocytosis; histiocytoid Sweet's syndrome