title: T-cell-rich angiomatoid polypoid pseudolymphoma of the skin: a clinicopathologic study of 17 cases and a proposed nomenclature.
abstract: BACKGROUND
  We describe a series of previously unreported, distinctive, polypoid solitary T-cell-rich cutaneous pseudolymphomas.
  
  
  METHODS
  The clinicopathologic features were examined in 17 cases.
  
  
  RESULTS
  Patient ages ranged from 16 to 71 years (mean = 38.5) with a female predominance (female : male = 14 : 3). All lesions, clinically diagnosed most often as pyogenic granuloma, presented as a solitary, polypoid, erythematous, papule ranging in size from 2.5 to 7.5 mm (mean = 5.8). Most occurred on the head and neck (7) and trunk (6) with other sites including the thigh (1), shoulder (1) and knee (1). A dense dermal infiltrate composed of mildly atypical lymphocytes with variable numbers of admixed plasma cells and histiocytes was prototypical. Commonly, there was an associated epidermal collarette (16/17), Grenz zone (11/17) or admixed eosinophils (8/17). Prominent vessels lined by plump endothelial cells, reminiscent of high endothelial venules of lymph nodes, were universal and some degree of telangiectasia was also common (12/17). CD3-positive T-cells consisted of an admixture of CD4-positive and CD8-positive forms (15/16). Multiple studies suggested polyclonality (seven cases). No recurrences after lesional excision were noted in the 17 patients with a follow-up range from 24 to 120 months (mean = 46.6).
  
  
  CONCLUSIONS
  Although these lesions share histopathologic features of the so-called acral pseudolymphomatous angiokeratoma of children (APACHE), they occur in a completely different clinical setting, present in solitary and polypoid fashion and are T-cell rich. We propose the diagnostic label T-cell-rich angiomatoid polypoid pseudolymphoma for this distinctive but presumably reactive lesion.
authors.affiliation: Department of Dermatopathology, St. John's Institute of Dermatology, St. Thomas' Hospital, London, UK.
authors.forename: Johannes F
authors.initials: JF
authors.lastname: Dayrit
authors.forename: Wei-Lien
authors.initials: WL
authors.lastname: Wang
authors.forename: Seng Geok Nicholas
authors.initials: SG
authors.lastname: Goh
authors.forename: Pratistadevi K
authors.initials: PK
authors.lastname: Ramdial
authors.forename: Alexander J F
authors.initials: AJ
authors.lastname: Lazar
authors.forename: Eduardo
authors.initials: E
authors.lastname: Calonje
mesh_terms: D000328:Adult; D000368:Aged; D015703:Antigens, CD / Q000096:biosynthesis; D015415:Biomarkers / Q000032:analysis; D005260:Female; D006801:Humans; D016130:Immunophenotyping; D008297:Male; D008875:Middle Aged; D016133:Polymerase Chain Reaction; D019310:Pseudolymphoma / Q000145:classification* / Q000473:pathology*; D012871:Skin Diseases / Q000145:classification* / Q000473:pathology*; D013601:T-Lymphocytes / Q000473:pathology*; D055815:Young Adult
chemical_list: D015703:Antigens, CD; D015415:Biomarkers