ObjectiveTo evaluate the Johns Hopkins Hospital experience with 136 thymomas over the past 40 years. This number of patients allowed quantitative estimation of the independent influence of common clinicopathologic risk factors using multivariate analysis. Summary Background DataThymomas vary widely in terms of recurrence and influence on overall survival. Several series have indicated the importance of initial tumor invasion, as well as the extent of surgical resection, as predictors of recurrence and survival after thymoma resection. However, findings have been equivocal when other predictors of prognosis were examined. MethodsThe authors evaluated 136 patients seen at the Johns Hopkins Hospital between 1957 and 1997 with a pathologic diagnosis of thymoma. Demographic information, clinical staging data, surgical and adjuvant treatment details, and patient follow-up data were obtained from the patient record and from detailed patient or family interviews. Microscopic sections of all 136 patients were reviewed by two pathologists blinded to the clinical data. All data were analyzed by multivariate Cox regression analysis, which allowed the quantification of the independent predictive value of 12 putative clinicopathologic prognostic indicators. ResultsCompleteness of follow-up was 99%, 99%, and 98% of eligible patients at 5, 10, and 15 years, respectively. Forty percent of the patients had associated myasthenia gravis and 27% had a secondary primary malignancy. Overall patient survival rates were 71%, 56%, 44%, 38%, and 33% at 5, 10, 15, 20, and 25 years, respectively. Overall, the thymoma-related mortality rate was 14%; the nonthymoma-related mortality rate was 26%. Incomplete resection, preoperative absence of myasthenia gravis, and advanced Lattes/Bernatz pathologic class were found to be independent predictors of poorer overall survival. ConclusionsThese findings support a policy of aggressive, complete surgical resection of all thymomas when feasible. Thymoma behaves as a rather indolent tumor, with most deaths from causes unrelated to thymoma or its direct treatment. Clinicians should have an increased awareness of the possibility of second primary malignancies in patients with thymoma.

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Immunohistochemical stains (IHC) stains for high molecular weight cytokeratin (HMWCK) may show the presence or absence of basal cells in a small focus of atypical glands helping to establish a benign or malignant diagnosis respectively. From January 1994 to the present, we have generated intervening unstained slides on all prostate needle biopsies for potential IHC stains for HMWCK because lesions may not survive deeper sectioning into the block. Of 1105 prostate needle biopsy cases seen at Johns Hopkins from January 1994 to December 1996, IHC staining for HMWCK was initially done on 94 (8.5%). To see whether lesions would still have been present for evaluation if we did not have intervening slides, we repeated the IHC stains for HMWCK off the paraffin blocks in 74 cases for which material was available for study. Care was taken not to trim the blocks. In 52 cases, the original HMWCK helped to establish a diagnosis; in 31 of these cases the lesion was not present on repeat IHC stains from the block. Of these 31 cases, the original HMWCK from intervening unstained slides helped to establish cancer (n = 23) or a benign (n = 8) diagnosis. The use of intervening unstained slides was critical to establish a diagnosis in 31 (2.8%) of 1105 prostate needle biopsies and saved the cost of repeat biopsy ($68,200) and spared these patients from a second surgical procedure.