胸腺上皮肿瘤分级的临床病理意义

Clinicopathological significance of grading on thymic epithelial tumors

目的 提出胸腺上皮肿瘤 (TET)分级标准 ,并探讨该分级与WHO组织学分型、临床分期的相关性及其临床病理学意义。方法 对 2 0 0例TET采用WHO病理分型和Masaoka临床分期 ,结合临床治疗和随访资料进行了系统的相关性研究并进行了TET分级。结果 胸腺瘤A型 8例(4 0 % ) ,AB型 6 8例 (34 0 % ) ,B1型 17例 (8 5 % ) ,B2型 39例 (19 5 % ) ,B3型 2 7例 (13 5 % ) ,C型 36例 (18 0 % ) ,其他 5例 (2 5 % )。组织学分型与预后的相关性有非常显著性意义 (P <0 0 0 1) ,A和AB型预后好 ,无一例患者死于肿瘤 ,B2、B3和C型较差。临床Ⅰ期 :96例 (4 8 0 % ) ,Ⅱ期 :2 6例 (13 0 % ) ,Ⅲ期 :6 5例 (32 5 % ) ,Ⅳ期 13例 (6 5 % )。临床分期与预后的相关性亦有非常显著性意义 (P <0 0 0 1) ,Ⅲ期和Ⅳ期预后较差。组织学分型与临床分期的相关性同样有非常显著性意义 (P <0 0 0 1) ,组织学分型提示在Ⅰ期、Ⅱ期TET中 ,B2、B3和C型的预后明显较其他类型差 (P <0 0 0 1)。根据TET的组织学、临床资料、生物学行为和预后情况提出了TET分级的建议 :胸腺瘤Ⅰ级、Ⅱ级、Ⅲ级和Ⅳ级 ,统计学分析表明TET分级与患者的治疗和预后的相关性有非常显著性意义 (P <0 0 0 1) ,Ⅰ级和Ⅱ级TET在根治术后仅需密切随访 。

Objective To study the clinicopathologic relevance of a thymic epithelial tumor (TET) grading standard with the WHO classification. Methods A grading system for TET was proposed based on the application of WHO histological typing of thymic tumors and analyzed in relation to clinical therapy results and follow up data of 200 TET cases. Results In this series, 8 patients (4.0%) belonged to type A, 68 (34.0%) were type AB, 17 (8.5%) were type B1, 39 (19.5%) were type B2, 27 (13.5%) were type B3 and 36 (18.0%) were type C. The remaining 5 cases were rare thymomas. The overall postoperative survival data showed highly significant differences among the histological subtypes ( P <0.001). Type A & type AB thymomas showed excellent prognosis, none of these patients died of tumor; in type B1, only 1 case (5.9%) died at 22 months postoperatively. Types B2, B3 and C thymomas shared the bad, worse and worst prognosis. Ninety six patients (48 0%) were in stage I, 26 (13.0%) in stage II, 65 (32.5%) in stage III and 13 (6.5%) in stage IV. Clinical stage is also highly significant in predicting survival ( P <0.001). It was found that tumor histology could predict survival expectancies well in stage I and stage II cases. It was also found that type B2, B3 and C thymomas had a statistically significant worse prognosis than type A, AB and B1 thymomas ( P <0 001). According to the histology, clinical data, biological behavior and prognosis, it is proposed that thymomas be divided into 4 grades: grade I, II, III and IV. Follow up is the best strategy for grade I & II patients after radical surgery. In this series, the 30 patients (15.0%) presenting clinical signs of myasthenia gravis were mostly in type B2 and B3 groups ( P <0.01). Conclusions The WHO classification for TET provides good pathological definitions and criteria for diagnosis, which can independently predict the invasiveness and prognosis of TET. TET grading is of use in unifying pathological and clinical findings, in selection of proper therapy and in predicting prognosis.