[Clinicopathologic analysis of 52 cases of thymic epithelial tumor].
OBJECTIVE
To study the clinicopathologic characteristics of thymic epithelial tumors and to evaluate the diagnostic reproducibility and clinical relevance of the 2004 WHO histologic classification system.


METHODS
The morphology and immunophenotype of 52 cases of thymic epithelial tumor were reviewed. The tumors were classified according to the new WHO classification system and the clinical data were analyzed.


RESULTS
Of the 52 cases studied, 45 were thymomas and 7 were thymic carcinomas. Amongst the 45 cases of thymoma, 6 (13.4%) were type A, 15 (33.3%) were type AB, 4 (8.9%) were type B1, 9 (20.0%) were type B2, 9 (20.0%) were type B3 and 2 (4.4%) were metaplastic thymoma. Amongst the 7 cases of thymic carcinoma, 6 were squamous cell carcinomas and 1 was neuroendocrine carcinoma. The commonest presentations were cough and chest pain. Some cases were incidentally discovered by routine physical examination. Thirteen cases (25.0%) of thymoma were associated with myasthenia gravis. CT scan showed that 49 cases (94.2%) were located in the anterior mediastinum. All cases of type A, AB and B1 thymoma and most cases of B2 thymoma appeared as well-defined homogeneous mass, whereas a few cases of type B2 thymoma and most cases of type B3 thymoma and thymic carcinoma were poorly demarcated and heterogeneous. According to Masaoka staging system, 20 cases (41.7%) belonged to stage I, 15 cases (31.3%) stage II, 11 cases (22.9%) stage III and 2 cases (4.1%) stage IV. The histologic subtypes of thymic epithelial tumors significantly correlated with the clinical stages (chi(2) = 32.5, P < 0.01).


CONCLUSIONS
The 2004 revision of WHO histologic classification system for thymic epithelial tumors shows a high degree of reproducibility. Correlation with the radiologic, clinical and prognostic parameters is helpful in determining the management strategy for individual patients.
Ma
Yu-qing
YQ
Department of Pathology, First Affiliated Hospital, Xinjiang Medical University, Urumqi 830054, China.
Miao
Na
N
Abulajiang
Gulinaer
G
Li
Qiao-xin
QX
Liu
Xia
X
Zhang
Wei
W
Wang
Chao-fu
CF
Wang
Jian
J
D000328:Adult; D000368:Aged; D000911:Antibodies, Monoclonal / Q000032:analysis; D018951:Antigens, CD20 / Q000378:metabolism; D018956:CD5 Antigens / Q000378:metabolism; D018278:Carcinoma, Neuroendocrine / Q000145:classification / Q000000981:diagnostic imaging / Q000378:metabolism / Q000473:pathology; D002294:Carcinoma, Squamous Cell / Q000145:classification / Q000000981:diagnostic imaging / Q000378:metabolism / Q000473:pathology*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007633:Keratins / Q000276:immunology; D008297:Male; D008875:Middle Aged; D009157:Myasthenia Gravis; D009364:Neoplasm Recurrence, Local; D009367:Neoplasm Staging; D011379:Prognosis; D018714:Radiotherapy, Adjuvant; D012189:Retrospective Studies; D013945:Thymoma / Q000145:classification / Q000000981:diagnostic imaging / Q000378:metabolism / Q000473:pathology*; D013953:Thymus Neoplasms / Q000145:classification / Q000000981:diagnostic imaging / Q000378:metabolism / Q000473:pathology*; D014057:Tomography, X-Ray Computed
D000911:Antibodies, Monoclonal; D018951:Antigens, CD20; D018956:CD5 Antigens; D007633:Keratins