5例甲状腺原发性恶性淋巴瘤通过临床分析及光镜、免疫组化观察，经LCA、L26、UCHL、Mac387、A-ACT、K、λ、IgA、IgG、IgM标记，结果显示肿瘤多数为B细胞性。甲状腺恶性淋巴瘤瘤细胞有IgA、K阳性表达与桥本氏甲状腺炎IgA阳性表达相同。瘤细胞浸润甲状腺滤泡上皮形成淋巴上皮病变，提示桥本氏甲状腺炎起源的恶性淋巴组织发生的淋巴瘤，属粘膜相关淋巴组织发生的淋巴瘤。临床特点生长缓慢，无甲状腺机能改变，5例均无转移，低度恶性，以手术切除为主，并加化疗，预后较好。本文并对其病因、发病机理及鉴别诊断进行讨论。 Five cases of primary malignant lymphoma of the thyroid gland were identified by clinical analysis, light microscopy, and immunohistochemical staining. LCA, L26, UCHL, Mac387, A-ACT, K, λ, IgA, IgG, and IgM were the markers. The results showed that the majority of tumors were B cell. Thyroid malignant lymphoma cells have IgA, K positive expression and Hashimoto’s thyroiditis IgA positive expression. Tumor cells infiltrate the thyroid follicular epithelium to form lymphoepithelial lesions, suggesting that lymphomas arising from malignant lymphoid tissues of Hashimoto’s thyroiditis are lymphomas of mucosa-associated lymphoid tissues. The clinical features were slow growth, no thyroid function changes, no metastasis in 5 cases, and low grade malignancy. Surgical resection was the main method, followed by chemotherapy, and the prognosis was good. This article discusses its etiology, pathogenesis and differential diagnosis.