*Department of Pathology, the Tumor Bank and Tumor Biology Laboratory, the departments of Statistics and Dermatology, University Hospital of Bordeaux †Departments of Pathology and Dermatology, University Hospital of Paris-Est Créteil ‡Departments of Pathology and Dermatology, University Hospital of Montpellier §Departments of Pathology and Dermatology, University Hospital of Paris, APHP ∥Departments of Pathology and Dermatology, University Hospital of Tours ¶Departments of Pathology and Dermatology, University Hospital of Lyon #Departments of Pathology and Dermatology, University Hospital of Clermont-Ferrand, France.
Am J Surg Pathol. 2013 Dec;37(12):1845-54. doi: 10.1097/PAS.0000000000000091.
Mycosis fungoides (MF), the most common primitive cutaneous T-cell lymphoma, can undergo transformation in about 10% of cases. Transformed mycosis fungoides (T-MF) is often associated with the appearance of a CD20 component. The aim of this study was to analyze whether such cells are reactive or lymphomatous and to evaluate their prognostic impact. Among 311 T-MFs from the French Cutaneous Lymphoma Study Group registry, we studied 148 cases. CD20 was expressed in 88 cases (59%). The proportion of CD20 cells among T-MF lesions was <10% for 54 cases (38%), 10% to 49% for 71 cases (81%), and >50% for 17 cases (19%). We focused the study on 23 cases that contained >50% CD20 cells. To evaluate the nature of the CD20 component, we used immunohistochemistry (2 anti-CD20 antibodies, L26 and 7D1 clones, and 2 other anti-B-cell antigen antibodies, CD22 and PAX5) and a double-stain immunofluorescence technique (anti-CD20 and anti-CD3 antibodies). The clonality of B cells was studied by polymerase chain reaction. Three profiles were observed. In 15 of the 23 cases, the CD20 cells were reactive. In 6 cases, CD20 protein was aberrantly expressed in T-MF lesions. Lastly, there were 2 composite lymphomas (T-MF infiltrate with a B-cell follicular lymphoma). In view of this series, we propose a simple algorithm to help pathologists evaluate the nature of the CD20 component associated with T-MF. Although statistically not significant, there was a trend toward a worse prognosis in the presence of >50% CD20 cells and of a nodular perifollicular pattern of this component.
蕈样肉芽肿（MF）是最常见的原发性皮肤 T 细胞淋巴瘤，约 10%的病例可发生转化。转化型蕈样肉芽肿（T-MF）常伴有 CD20 成分的出现。本研究旨在分析这些细胞是反应性的还是淋巴瘤性的，并评估其预后影响。在法国皮肤淋巴瘤研究组登记处的 311 例 T-MF 中，我们研究了 148 例。CD20 在 88 例（59%）中表达。在 T-MF 病变中，CD20 细胞的比例<10%的有 54 例（38%），10%-49%的有 71 例（81%），>50%的有 17 例（19%）。我们将研究重点放在含有>50%CD20 细胞的 23 例病例上。为了评估 CD20 成分的性质，我们使用了免疫组织化学（2 种抗 CD20 抗体，L26 和 7D1 克隆，以及 2 种其他抗 B 细胞抗原抗体，CD22 和 PAX5）和双染免疫荧光技术（抗 CD20 和抗 CD3 抗体）。通过聚合酶链反应研究了 B 细胞的克隆性。观察到三种模式。在 23 例中的 15 例中，CD20 细胞是反应性的。在 6 例中，CD20 蛋白在 T-MF 病变中异常表达。最后，有 2 例复合淋巴瘤（T-MF 浸润伴 B 细胞滤泡性淋巴瘤）。鉴于本系列，我们提出了一种简单的算法来帮助病理学家评估与 T-MF 相关的 CD20 成分的性质。尽管统计学上无显著意义，但在存在>50%CD20 细胞和该成分结节性毛囊周围模式时，存在预后不良的趋势。
