Thymic Carcinomas and Second Malignancies: A Single-Center Review

SIMPLE SUMMARY: Thymic carcinoma (TC) is a rare neoplasm that accounts for less than 0.01% of all tumors. The aim of our retrospective observational analysis is to review the incidence of second cancers associated with this histological type of cancer. We identified 92 patients with TC referred to our consultation practice and reviewed their clinical data for diagnosis of another cancer pre- or post-diagnosis of TC. This resulted in identification of 14 patients with additional cancers. The incidence of second cancer is similar to that observed in thymomas. ABSTRACT: Thymic carcinomas account for less than 0.01% of new cancer diagnoses annually and are more aggressive than thymomas. Autoimmune disorders have been associated with thymomas and only recently with thymic carcinomas. Second malignancies are well described after thymomas. The aim of this study was to analyze the incidence of second malignancies in patients with thymic carcinomas. All cases of thymic carcinomas were identified from the pathology archives of Indiana University. Histological materials were reviewed and further correlated with clinical data to identify incidence of second cancers in patients with thymic carcinomas. Histological material was available for review in 92 cases of thymic carcinoma. Clinical data were available for 85 patients. Fourteen of these (16.5%) patients had a second malignancy; these included small cell lung carcinoma, “testicular cancer”, embryonal carcinoma, seminoma, breast carcinoma (two cases), prostatic adenocarcinoma, Hodgkin’s lymphoma, thyroid carcinoma, bladder carcinoma (two cases), renal cell carcinoma, and melanoma. The latter could precede, be concurrent with, or follow the diagnosis thymic carcinoma. The incidence of second cancers in patients with thymic carcinomas is similar to that reported for thymomas. Abnormalities in immunological surveillance may be responsible for this high incidence of second malignancies in thymic tumors.