Thymoma

Despite being the most common epithelial tumor in the anterior mediastinum, thymomas are uncommon tumors, as mediastinal pathology is unusual in general. There is controversy in terms of classification, staging, and clinical outcomes. Most publications about thymomas comprise small series of cases in which the authors have proposed their own views about classification, staging, or clinical behavior. In more recent times, some issues around thymomas have been resolved, but nevertheless, it is important to highlight that the published literature is rather empiric at best with little detail and with a wide spectrum of disparity in terms of pathology. It is important to clarify that thymoma is not the benign counterpart of thymic carcinoma nor is thymic carcinoma the malignant form of thymoma. Both conditions, thymoma and thymic carcinoma, represent unique clinicopathological entities, which require proper delineation not only for diagnostic purposes but also for prognosis, treatment, and outcomes. The clinical outcome in patients with thymoma is closely linked to the pathological stage at the time of diagnosis. In tumors that are encapsulated or minimally invasive, it is possible that only surgical resection offers a good clinical outcome while in those patients with invasive disease other treatment options such as radiation therapy and/or chemotherapy become possible alternatives.