Bosisio Francesca M, Cerroni Lorenzo
*Research Unit of Dermatopathology, Department of Dermatology, Medical University of Graz, Austria; and †Department of Surgical Sciences, Milano-Bicocca State University, Monza, Italy.
Am J Dermatopathol. 2015 Feb;37(2):115-21. doi: 10.1097/DAD.0000000000000258.
T-follicular helper (Tfh) lymphocytes represent the neoplastic cells of angioimmunoblastic T-cell lymphoma and have been observed also in several cutaneous T-cell lymphomas (CTCLs) and extracutaneous T-cell lymphomas, including peripheral T-cell lymphoma, not otherwise specified, mycosis fungoides (MF), cutaneous CD4 small/medium T-cell lymphoma (CD4SMTCL), and Sezary syndrome. We studied a large number of different types of primary CTCL for expression of Tfh markers, including 36 biopsies from 21 patients with MF (with sequential biopsies from patch stage and tumor stage of 15 patients), 13 patients with CD4SMTCL, 9 with lymphomatoid papulosis, 11 with cutaneous anaplastic large cell lymphoma (cALCL), 2 with cutaneous γ/δ T-cell lymphoma, 8 with subcutaneous panniculitis-like T-cell lymphoma, 3 with cutaneous aggressive epidermotropic CD8 cytotoxic T-cell lymphoma, 6 with cutaneous peripheral T-cell lymphoma, not otherwise specified, and 1 with Sezary syndrome. Expression of at least 3 of 5 markers (PD-1, CXCL-13, ICOS, Bcl-6, and CD10) in >10% of tumor cells was observed in 33 biopsies (MF = 20; CD4SMTCL = 11; 1 each cutaneous anaplastic large cell lymphoma and subcutaneous panniculitis-like T-cell lymphoma, respectively). Our study shows that a Tfh phenotype is very common in MF and CD4SMTCL but can be observed rarely also in other types of CTCL. Expression of Tfh markers should not be used for classification of any entity of CTCL and may only integrate other immunohistochemical stainings for a more accurate characterization of these disorders. Precise distinction of Tfh-positive CTCLs from secondary skin manifestations of angioimmunoblastic T-cell lymphoma cannot rest on demonstration of a Tfh phenotype alone and should be achieved by a synthesis of clinical, histological, and phenotypic features.
滤泡辅助性T（Tfh）淋巴细胞是血管免疫母细胞性T细胞淋巴瘤的肿瘤细胞，在多种皮肤T细胞淋巴瘤（CTCL）和皮肤外T细胞淋巴瘤中也有发现，包括未另行指定的外周T细胞淋巴瘤、蕈样肉芽肿（MF）、皮肤CD4小/中T细胞淋巴瘤（CD4SMTCL）和Sezary综合征。我们研究了大量不同类型的原发性CTCL的Tfh标志物表达情况，包括21例MF患者的36份活检标本（其中15例患者有斑块期和肿瘤期的连续活检标本）、13例CD4SMTCL患者、9例淋巴瘤样丘疹病患者、11例皮肤间变性大细胞淋巴瘤（cALCL）患者、2例皮肤γ/δ T细胞淋巴瘤患者、8例皮下脂膜炎样T细胞淋巴瘤患者、3例皮肤侵袭性亲表皮CD8细胞毒性T细胞淋巴瘤患者、6例未另行指定的皮肤外周T细胞淋巴瘤患者以及1例Sezary综合征患者。在33份活检标本中观察到超过10%的肿瘤细胞表达5种标志物（PD-1、CXCL-13、ICOS、Bcl-6和CD10）中的至少3种（MF = 20；CD4SMTCL = 11；分别有1例皮肤间变性大细胞淋巴瘤和皮下脂膜炎样T细胞淋巴瘤）。我们的研究表明，Tfh表型在MF和CD4SMTCL中非常常见，但在其他类型的CTCL中也很少见。Tfh标志物的表达不应被用于CTCL任何实体的分类，仅可与其他免疫组织化学染色相结合以更准确地表征这些疾病。Tfh阳性CTCL与血管免疫母细胞性T细胞淋巴瘤的继发性皮肤表现的精确区分不能仅依靠Tfh表型的证明，而应通过综合临床、组织学和表型特征来实现。
