胸腺黏膜相关淋巴组织结外边缘区淋巴瘤9例临床病理分析

目的探讨胸腺黏膜相关淋巴组织结外边缘区(extranodal marginal zone lymphoma of mucosa-associated lymphoid tissue,MALT)淋巴瘤的临床病理学特征、免疫表型、分子特征及鉴别诊断。方法回顾性分析9例胸腺MALT淋巴瘤的临床资料、病理学形态、免疫表型及分子遗传学特征,结合文献对其临床病理学特点进行探讨。结果9例胸腺原发MALT淋巴瘤患者年龄35~72岁(平均50岁),男性2例,女性7例。5例患者体检发现纵隔占位,2例表现为胸痛、咳嗽及四肢面部浮肿等症状。4例患者既往伴有自身免疫性疾病。镜下肿瘤主要由小到中等的淋巴细胞样细胞构成,弥漫浸润生长,其内见大小不等的囊肿形成,囊腔内可见胆固醇结晶沉积,瘤细胞侵犯囊壁及胸腺小体而形成淋巴上皮病变。免疫表型:9例肿瘤细胞均表达B细胞标志物(CD20、CD79α、Pax-5),基因重排均显示单克隆性B细胞增生,FISH检测未见MALT1基因断裂。结论胸腺MALT淋巴瘤较少见,属于低度恶性肿瘤,多数伴有自身免疫性疾病。单一形态的瘤细胞结合免疫表型及基因重排可明确诊断,警惕漏诊或过诊。手术完整切除后密切随访即可。

Thymic extranodal marginal zone lymphoma of mucosa associated lymphoid tissue:a clinicopathologic analysis of 9 cases

Purpose To explore the clinicopathological characteristics,immunophenotype,molecular feature and differential diagnosis of thymic extranodal marginal zone lymphoma of mucosa associated lymphoid tissue(MALT)lymphoma.Methods The clinical data,pathological morphology,immunophenotype and molecular genetic charcteristics of 9 cases of thymic MALT lymphoma were analyzed retrospectively,and to discussed their clinicopathological features with a review of the relevant literatures.Results 9 cases of primary thymic MALT lymphoma were aged 35-72(mean 50)years old,there were 2 males and 7 females.7 cases with mediastinal lesions were observed by medical examination,and 2 cases had symptoms,such as chest pain,cough,edema of limbs and face.4 cases had autoimmune disorders in the past.Microscopically,the tumor was mainly composed of small to medium-sized lymphocytoid cells with diffuse infiltration growth.Cysts of different sizes were seen within the tumor,cholesterol clefts was observed in the lumen,and lymphoepithelial lesions were formed when tumor cells invaded the cystic wall and Hassall’s corpuscle.Immunophenotypically,all the tumour cells expressed B cell markers(CD20,CD79α,Pax-5),and gene rearrangement showed monoclonal B cell hyperplasia.No MALT1 gene split signal was detected by FISH.Conclusion Thymic MALT lymphoma is rare and low-grade malignant tumor,most of which are accompanied by autoimmune diseases.The monomorphic cells combined with immunophenotype and genetic rearrangement can be clearly diagnosed,but need to guard against missed or over-diagnosed.Close follow-up after surgery is required.