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The frequency of dual TCR-PCR clonality in granulomatous disorders

Authors


Jinah Kim, MD, PhD, Department of Pathology, Stanford University Medical Center, 300 Pasteur Drive, L-235, MC 5324, Stanford University Medical Center, Stanford, CA 94305, USA
Tel: +650 736 1068
Fax: +650 723 7409
e-mail: jinahkim@stanford.edu

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.

Dabiri S, Morales A, Ma L, Sundram U, Kim YH, Arber DA, Kim J. The frequency of dual TCR-PCR clonality in granulomatous disorders.

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