title: The frequency of dual TCR-PCR clonality in granulomatous disorders.
abstract: BACKGROUND
  A granulomatous infiltrate in association with cutaneous T-cell lymphoma is uncommon. The diagnosis of mycosis fungoides can be difficult in the setting of an exuberant granulomatous infiltrate that obscures the neoplastic lymphoid infiltrate, thereby mimicking a granulomatous dermatitis. Therefore, the clinical context and supplemental molecular analysis, such as the demonstration of a monoclonal T-cell population, may assist in diagnosis. Monoclonal T-cell populations have been reported in association with inflammatory conditions and serve as a diagnostic pitfall. The frequency of T-cell clonality in association with granulomatous dermatitides has not yet been established.
  
  
  METHODS
  We identified 29 patients with granulomatous dermatitis who had biopsies at two distinct body sites. Results were correlated with clinical follow up and with clonal T-cell receptor-gamma chain rearrangement as detected by polymerase chain reaction-based analysis (dual TCR-PCR).
  
  
  RESULTS
  Clinical follow up was obtained in 17 of 29 cases (58.6%). Twenty-five of 29 cases of granulomatous dermatitis lacked T-cell monoclonality. Three cases of granuloma annulare contained a T-cell clone in one of the two biopsies. One case of necrobiotic xanthogranuloma showed an identical T-cell clone in multiple biopsies.
  
  
  CONCLUSIONS
  The use of dual TCR-PCR analysis, that is, T-cell clonality analysis in biopsy specimens from two different sites, serves as an adjunct to assist in distinguishing granulomatous inflammatory reactions from granulomatous T-cell lymphoma, including granulomatous mycosis fungoides. The occasional finding of a T-cell clone in a granulomatous dermatitis underscores the importance of clinicopathological correlation in daily diagnosis.
authors.affiliation: Department of Pathology, Stanford University Medical Center, Stanford, CA 94305, USA.
authors.forename: Salma
authors.initials: S
authors.lastname: Dabiri
authors.forename: Anjali
authors.initials: A
authors.lastname: Morales
authors.forename: Lisa
authors.initials: L
authors.lastname: Ma
authors.forename: Uma
authors.initials: U
authors.lastname: Sundram
authors.forename: Youn H
authors.initials: YH
authors.lastname: Kim
authors.forename: Daniel A
authors.initials: DA
authors.lastname: Arber
authors.forename: Jinah
authors.initials: J
authors.lastname: Kim
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001706:Biopsy; D002648:Child; D002675:Child, Preschool; D003937:Diagnosis, Differential; D005260:Female; D005500:Follow-Up Studies; D006105:Granulomatous Disease, Chronic / Q000175:diagnosis / Q000473:pathology; D006801:Humans; D008297:Male; D008875:Middle Aged; D009182:Mycosis Fungoides / Q000235:genetics* / Q000473:pathology*; D016133:Polymerase Chain Reaction; D016692:Receptors, Antigen, T-Cell, gamma-delta / Q000235:genetics*; D012878:Skin Neoplasms / Q000235:genetics* / Q000473:pathology*; D013601:T-Lymphocytes / Q000473:pathology*
chemical_list: D016692:Receptors, Antigen, T-Cell, gamma-delta