γδ T‐cell in cutaneous and subcutaneous lymphoid infiltrates: malignant or not?

T‐cell receptor‐δ expression and γδ+ T‐cell infiltrates in primary cutaneous γδ T‐cell lymphoma and other cutaneous T‐cell lymphoproliferative disorders

“…Numerous γδ expressing T-cells can be found not only in GDTCL, but also in low-grade CTCL, CLPDs 14 , and inflammatory self-limited and indolent skin conditions 10, 17, 20, 21 In our study, 13 cases with typically indolent CTCL and CLPDs were shown to have lymphocytic infiltrates with 10%–25% TCRδ positivity, including 9 MF cases, 2 SPTCLs and 2 CD30-positive LPDs. One case of CD30-positive LPD showed TCRδ expression in 80–90% of the T-cell infiltrate and negative TCRβ labeling.…”

“…It has been suggested that these cells may represent either a subset of the malignant clone or a reactive T-cell population. 20 While we did not comparatively assess the intensity of staining within the different compartments of individual patients’ infiltrates in this study, we did observe qualitative differences in staining between small peripheral or intraepidermal TCRδ+ cells and larger clearly neoplastic cells. Comprehensive characterization of these subsets may help to better understand these diseases in the future.…”

“…Our findings align more closely with reports of intraepidermal MF-like GDTCL noted to evolve into aggressive cytotoxic lymphomas after many years of follow up. 20 We concur that caution is warranted when following such patients. Of note, we did not include CD4−/CD8−, TCRδ high patch/plaque type T-cell lymphomas within our MF cohort, as we feel that the follow-up on these cases is too limited for meaningful classification.…”

NK/T-cell lymphoma, nasal type, γδ T-cell lymphoma, and CD8-positive epidermotropic T-cell lymphoma—clinical and histopathologic features, differential diagnosis, and treatment

“…PCGDTCL was classified as a provisional cutaneous lymphoma entity by the WHO/EORTC in 2005 1 and as a definitive entity in the 2008 WHO lymphoma classification. 39 A lack of reliable immunohistochemical markers for the detection of the TCR γ/δ chains, controversy over the positive predictive value of absent TCR α/β labeling, the presence of reactive γδ T-cell subsets in indolent cutaneous lymphoma types, 42 and inexperience in the interpretation of these infiltrates have made this a challenging diagnosis.…”

“…Moreover, lymphoid infiltrates with a predominant γδ phenotype are not unequivocally associated with aggressive disease and can be found in cases of indolent lesions such as lym-phomatoid papulosis and pityriasis lichenoides. 42,48 However, the majority of PCGDTCL can be efficiently diagnosed with an adequate cutaneous punch or core biopsy and accurate clinicopathologic correlation. Often difficulties in diagnosing this disease arise from inadequate (eg, too superficial or too narrow) biopsy material or poor clinical history.…”