探讨ALK阳性的大B细胞淋巴瘤（ALK^＋LBCL）的临床病理学特征、免疫组化特点及鉴别诊断。

回顾性分析泰安市中心医院2018年经病理诊断的2例ALK^＋LBCL，收集患者的临床资料，观察ALK^＋LBCL的病理形态特点和免疫表型，并复习相关文献。

2例ALK^＋LBCL患者均为男性，年龄分别为45岁和50岁，均因颈部多发淋巴结肿大就诊。淋巴结切除活检示淋巴结结构破坏，肿瘤细胞成巢团状分布，可见瘤细胞侵犯淋巴窦。肿瘤细胞体积大，呈浆母细胞样和免疫母细胞样分化，免疫组化不表达常用的B细胞标记物（CD20、CD79a、PAX-5）和T细胞标记物（CD3、CD5），表达浆细胞标记物（CD38、CD138、MUM-1），kappa（＋），Lambda（-），EMA（＋），ALK呈胞浆颗粒状阳性。随访6~11个月，患者均存活。

ALK^＋LBCL是一种罕见的侵袭性B细胞淋巴瘤，与多种肿瘤在细胞形态及免疫表型上有重叠，误诊率较高。ALK抑制剂也许会成为ALK^＋LBCL新的治疗选择。

To investigate the clinicopathological and immunohistochemical features and differential diagnosis of ALK⁺ large B cell lymphoma (ALK⁺ LBCL).

The clinical data of two patients treated at the Tai′an City Central Hospital were analyzed retrospectively. The histopathologic features and immunophenotype of ALK⁺ LBCL were observed and the related literature was reviewed.

The age of the two male patients was 45 and 50 years old, respectively. Both of them presented with multiple enlarged lymph nodes on the neck. Lymphadenectomy biopsy showed that lymph node structure was destroyed and tumor cells were arranged in nests or invading the lymphatic sinus. The tumor cells were large in size with an immunoblastic or plasmablastic microscopical appearance. They did not express B-lineage markers (CD20, CD79α, and PAX-5) or T-lineage markers (CD3 and CD5). However, ALK, EMA, and plasmacytic markers, including CD138, CD38, and MUM-1, were characteristically expressed. Two patients were alive during the follow-up period of 6-11 months.

ALK⁺ LBCL is a rare aggressive B-cell lymphoma with unique morphologic, immunohistochemical, and cytogenetic characteristics. As it overlaps with many tumors in morphology and immunophenotype, the chance of misdiagnosis is relatively high. ALK inhibitors may become a new treatment option for ALK⁺ LBCL.