THYMOMA: A clinicopathological correlation of 1470 cases

Publication date: Available online 26 August 2017
Source:Human Pathology
Author(s): Annikka Weissferdt, Neda Kalhor, Justin A. Bishop, Se Jin Jang, Jae Ro, Fredrik Petersson, Bingcheng Wu, Gerald Langman, Hollie Bancroft, Yalan Bi, Yunxiao Meng, Filomena Medeiros, Hans Brunnstrom, Dominic Spagnolo, Siaw Ming Chai, Andrew Laycock, Paul E. Wakely, Goran Elmberger, Fernando A. Soares, Antonio H. Campos, Derya Gumurdulu, Isabel Alvarado-Cabrero, Domenico Coppola, Arlene M. Correa, David Rice, Reza J. Mehran, Boris Sepesi, Garrett Walsh, Larry Kaiser, Cesar A. Moran
We present 1470 surgical resections for thymoma identified in the pathology files of 14 institutions from 11 countries with the purpose to determine and correlate a simplified histological classification of thymoma and pathological staging with clinical outcome. The study population was comprised of 720 men and 750 women between the ages of 12 and 86years (average: 54.8years). Clinically 137 patients (17%) had a history of myasthenia gravis, 31 patients (3.8%) of other autoimmune disease, and 55 (6.8%) patients of another neoplastic process. Surgical resection was performed in all patients. Histologically, 1284 (87.13%) cases were thymomas (World Health Organization [WHO] types A, B1, and B2, and mixed histologies), and 186 (12.7%) were atypical thymomas (WHO type B3). Of the entire group, 630 (42.9%) were encapsulated thymomas and 840 (57.9%) were invasive thymomas in different stages. Follow-up information was obtained in 1339 (91%) patients, who subsequently were analyzed by univariate and multivariate statistical analysis. Follow-up ranging from 1 to 384months was obtained (mean: 69.2months) showing tumor recurrence in 136 patients (10.1%), while 227 died- 64 (28.2%) due to tumor and 163 (71.8%) due to other causes. Statistical analysis shows that separation of these tumors into- thymoma and atypical thymoma- is statistically significant (P=.001), while tumor staging into categories of encapsulated, minimally invasive, and invasion into adjacent organs offers a meaningful clinical assessment with a p=value of 0.038. Our findings suggest that our simplified histological schema and pathological staging system are excellent predictors of clinical outcome.



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