title: Clonality in sarcoidosis, granuloma annulare, and granulomatous mycosis fungoides.
abstract: The histological discrimination of granulomatous cutaneous T-cell lymphomas (CTCLs) from reactive granulomatous disorders such as sarcoidosis and granuloma annulare (GA) may be difficult due to overlapping histological features. We analyzed the T-cell receptor gene rearrangement in sarcoidosis and GA to investigate the value of the detection of clonal T cells as an adjunctive diagnostic marker in the differentiation between sarcoidosis and GA versus granulomatous CTCLs. Rearrangement of T-cell receptor γ genes was examined by the use of automated high-resolution polymerase chain reaction fragment analysis in 35 cases of sarcoidosis and 15 cases of GA and compared with a series of 19 cases of granulomatous CTCLs. A monoclonal T-cell population was found in none of the cases of sarcoidosis and in 2 of 15 cases of GA (13%). In granulomatous CTCLs, a neoplastic T-cell clone was detected in 94%. Presence of clonal T cells argues in favour of a granulomatous CTCL, while a polyclonal T-cell population makes the presence of a sarcoidosis or a GA more likely. The analysis of T-cell clonality is a useful diagnostic adjunct in the differentiation between sarcoidosis and GA from granulomatous CTCLs.
authors.affiliation: Kempf and Pfaltz Histological Diagnostics, Zürich, Switzerland.
authors.forename: Katrin
authors.initials: K
authors.lastname: Pfaltz
authors.forename: Katrin
authors.initials: K
authors.lastname: Kerl
authors.forename: Gabriele
authors.initials: G
authors.lastname: Palmedo
authors.forename: Heinz
authors.initials: H
authors.lastname: Kutzner
authors.forename: Werner
authors.initials: W
authors.lastname: Kempf
mesh_terms: D000328:Adult; D000368:Aged; D002999:Clone Cells; D003937:Diagnosis, Differential; D005260:Female; D015334:Gene Rearrangement, gamma-Chain T-Cell Antigen Receptor / Q000235:genetics*; D006099:Granuloma / Q000175:diagnosis / Q000235:genetics; D016460:Granuloma Annulare / Q000175:diagnosis / Q000235:genetics*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009182:Mycosis Fungoides / Q000175:diagnosis / Q000235:genetics*; D012507:Sarcoidosis / Q000175:diagnosis / Q000235:genetics*; D012878:Skin Neoplasms / Q000175:diagnosis / Q000235:genetics*; D055815:Young Adult