Department of Pathology, Fudan University Shanghai Cancer Center, 270 Dong-an Road, Xuhui District, Shanghai, 200032, China.
Department of Oncology, Shanghai Medical College, Fudan University, Shanghai, 200032, China.
Diagn Pathol. 2021 Jan 5;16(1):1. doi: 10.1186/s13000-020-01059-y.
Anaplastic large cell lymphoma (ALCL) with uniform CD56 expression is a rare condition, that has been described in limited literature, and its clinicopathological features have not yet been well illustrated. The aim of our study was to fully investigate the clinical, histological, immunohistochemical and molecular features of CD56+ ALCL.
The clinical and histological characteristics of CD56+ ALCL cases were retrospectively evaluated. The immunohistochemical phenotype, status of Epstein-Barr virus (EBV) and T-cell receptor (TCR) gene rearrangement were examined. Overall survival was also analyzed.
Eighteen (5.8%) cases with diffuse CD56 expression were identified out of 313 archived ALCL cases with CD56 test. CD56 expression was significantly higher in ALK+ systemic ALCLs (sALCLs) (13/64, 20.3%) than in ALK- sALCLs (3/101, 3.0%) (p < 0.001) as well as primary cutaneous ALCLs (2/148, 1.4%) (p < 0.001). Regarding the CD56+ ALK+ sALCLs, the median age was 20 years (range, 8-60 years) with a male-to-female ratio of 2.3:1, and these cases more frequently affected extranodal sites (11/38, 28.9%) rather than lymph nodes (2/26, 7.7%) (p = 0.038). Eleven (84.6%) cases presented with stage I-II diseases, which was significantly more than their CD56- ALK+ counterparts (45.5%) (p = 0.015). Histologically, 2 ALK+ cases were of small cell variant and all the others displayed characteristic morphology of classic ALCL. Regarding the immunophenotype, both CD30 and CD56 were diffusely positive in all cases. CD3, CD43, anaplastic lymphoma kinase-1 (ALK1), TIA-1, EMA expression was observed in 30.8% (4/13), 90.9% (10/11), 100% (13/13), 100% (9/9), and 80.0% (8/10) cases, respectively. EBV infection was consistently absent. Monoclonal TCR gene rearrangement was found in 100% (5/5) of investigated ALK+ cases. Chemotherapy with a CHOP regimen was most frequently employed. The 3-year overall survival (OS) rate for CD56+ ALK+ patients was 92.0%, compared with 73.0% for their CD56- counterparts, but there was no significant difference in OS between the two groups (p = 0.264).
Uniform CD56 expression is an unexpected condition in ALCL. Of ALK+ ALCLs, CD56 expression correlated with a high frequency of early stage and an extranodal predominance. It is of great importance to raise awareness of this condition and familiarity with its characteristic features to avoid diagnostic and therapeutic pitfalls. Further investigations are warranted for a better understanding of this unusual phenotype and the significance of CD56 expression in ALCL.
具有均匀 CD56 表达的间变大细胞淋巴瘤（ALCL）是一种罕见的疾病，仅在有限的文献中有所描述，其临床病理特征尚未得到充分阐明。本研究旨在全面研究 CD56+ALCL 的临床、组织学、免疫组织化学和分子特征。
回顾性评估 CD56+ALCL 病例的临床和组织学特征。检查了 EBV 和 TCR 基因重排的免疫表型、状态。还分析了总生存率。
在 313 例存档的 CD56 检测 ALCL 病例中，鉴定出 18 例（5.8%）弥漫性 CD56 表达病例。ALK+系统性 ALCL（sALCL）（13/64，20.3%）中 CD56 表达明显高于 ALK-sALCL（3/101，3.0%）（p<0.001）和原发性皮肤 ALCL（2/148，1.4%）（p<0.001）。关于 CD56+ALK+sALCL，中位年龄为 20 岁（范围 8-60 岁），男女比例为 2.3:1，这些病例更常累及结外部位（11/38，28.9%）而不是淋巴结（2/26，7.7%）（p=0.038）。11 例（84.6%）表现为 I-II 期疾病，明显多于 CD56-ALK+病例（45.5%）（p=0.015）。组织学上，2 例 ALK+病例为小细胞变异型，其余均表现为经典 ALCL 的特征形态。关于免疫表型，所有病例均弥漫性表达 CD30 和 CD56。30.8%（4/13）、90.9%（10/11）、100%（13/13）、100%（9/9）和 80.0%（8/10）的病例分别观察到 CD3、CD43、间变性淋巴瘤激酶-1（ALK1）、TIA-1、EMA 表达。均未发现 EBV 感染。在所有研究的 ALK+病例中均发现单克隆 TCR 基因重排。最常使用 CHOP 方案进行化疗。CD56+ALK+患者的 3 年总生存率（OS）为 92.0%，而 CD56-患者为 73.0%，但两组之间的 OS 无显著差异（p=0.264）。
在 ALCL 中，均匀的 CD56 表达是一种意外的情况。ALK+ALCL 中，CD56 表达与早期和结外优势的高频率相关。提高对这种情况的认识并熟悉其特征对于避免诊断和治疗陷阱非常重要。需要进一步研究以更好地理解这种不寻常的表型和 CD56 在 ALCL 中的表达意义。
