Thymic Neoplasms: a Clinical Update

Abstract

Thymoma is a unique neoplasm of the anterior mediastinum that is frequently associated with indolent growth and a variety of paraneoplastic syndromes. One third of cases are detected during the evaluation of myasthenia gravis. Classification systems of thymoma have limited ability in accurately predicting prognosis and course of disease. Thus, staging is the only way to predict clinical behavior. Encapsulated tumors that are surgically resected carry the best prognosis. Adjuvant radiotherapy is recommended for incompletely excised and most invasive thymomas. Chemotherapy in anthracycline-based chemotherapy remains the most effective chemotherapy for neoadjuvant, adjuvant or palliative treatment.

Malignant Thymoma with Metastasis Associated with Paraneoplastic Myasthenia Gravis

“…Th ey account for 20% of anterior mediastinal neoplasms in adults, with an incidence of 0.15 per 100,000 person-years (5). Th e World Health Organization classifi cation distinguishes between subtypes of thymoma (subtype type A, AB, B1, B2, B3) and thymic carcinoma (type C) depending on histologic appearance (6).…”

“…Hourossadat Hashemi Jazi, MD, David M. Harmon, BS, Tuan Tran, MD, and Claude Denham, MD exhibits aggressive clinical behavior, atypical cytology, and poor prognosis (5). Both thymoma and thymic carcinoma may invade surrounding tissue such as the mediastinum, pericardium, and pleura.…”

Development of combined thymic carcinoma and thymoma in an extrathymic lesion during long follow-up for recurrent thymoma

“…Thymoma is the most common neoplasm in the anterior mediastinum and ~70% of the cases are well encapsulated, and therefore considered benign (1). However, thymoma has malignant potential and may invade into adjacent organs within the thorax or form distant metastasis.…”

“…However, thymoma has malignant potential and may invade into adjacent organs within the thorax or form distant metastasis. By contrast, thymic carcinoma differs from thymoma, not only morphologically, but also biologically (1)(2)(3)(4). The majority of cases of thymic carcinoma appear to arise de novo, however, there have been rare reports of their occurrence and/or coexistence in thymomas (5)(6)(7)(8)(9)(10)(11)(12)(13)(14).…”

Molecular Markers for Patients with Thymic Malignancies: not Feasible at Present?

“…Differently from thymomas, the epithelial component proliferates of thymic carcinomas are not characterized by the typical lymphocytic admixture (Kelly, 2013). The clinical manifestations of thymomas and thymic carcinomas generally reflect tumor invasion, local compression of neighboring organs, and distant metastasis (Mikhail et al, 2012). The paraneoplastic syndromes, such as myasthenia gravis, red cell aplasia, autoimmune diseases, and opportunistic infections, are uncommon in thymic carcinomas.…”