Evaluation of a histogenetic classification for thymic epithelial tumours.
We reviewed 87 thymic epithelial tumours from Chinese patients and typed them according to the Marino and Müller-Hermelink classification as updated by Kirschner and Müller-Hermelink in 1989. Related categories were grouped for statistical analyses: group 1, medullary thymoma and mixed thymoma; group 2, cortical predominant thymoma; group 3, cortical thymoma and well-differentiated thymic carcinoma; group 4, other thymic carcinomas; and group 5, unclassified. Group 3 tumours were more frequently associated with the myasthenia gravis syndrome compared with group 1 tumours (P = 0.001). They also presented at a more advanced stage. Groups 1 and 2 showed an excellent prognosis (100% survival at 10 years). The 10-year survival for groups 3 and 4 patients was 40% and 30% respectively. Pure medullary thymoma made up a higher proportion of our cases (10.3%) than those of a similar Caucasian study (5.3%). The eight thymic carcinomas (group 4) included two thymic lymphoepitheliomas. We conclude that the histogenetic classification evaluated shows a clear correlation with prognosis and clinical features, even when tested on separate geographic groups, where pathogenetic factors may be different. A common approach to classification of thymic epithelial tumours would greatly facilitate future studies on these possible differences.
Department of Pathology, University of Hong Kong, Queen Mary Hospital, Pokfulam.
F C
FC
Ho
K H
KH
Fu
S Y
SY
Lam
S W
SW
Chiu
A C
AC
Chan
H K
HK
Müller-Hermelink
D000328:Adult; D000368:Aged; D002277:Carcinoma / Q000145:classification* / Q000453:epidemiology / Q000473:pathology; D002681:China; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D011237:Predictive Value of Tests; D013945:Thymoma / Q000145:classification* / Q000473:pathology; D013953:Thymus Neoplasms / Q000145:classification* / Q000453:epidemiology / Q000473:pathology