Thymoma and thymic carcinoma

Abstract

Thymoma and thymic carcinoma are an extremely heterogeneous group of neoplastic lesions with an exceedingly wide spectrum of morphologic appearances. They show different presentations with a variable and unpredictable evolution ranging from an indolent non-invasive attitude to a highly infiltrative and metastasising one. Prognosis can be predicted on the basis of a number of variables, mainly staging, the WHO histological pattern and diameter of the tumour. Complete surgical resection is certainly the gold standard to achieve cure. However, especially in patients with lesions at advanced stage, complete resection may be difficult and recurrence often occurs; at these stages, disease-free long-term survival may be difficult to be accomplished. Chemo- and radiotherapy protocols have been designed to complete surgical treatment and improve results in inoperable patients as well, based on the reported sensitivity of thymic tumours to these treatment modalities. The integration of clinical staging and histology, with the new histogenetic morphological classification, has contributed to design multimodality treatment protocols that help to improve prognosis. Induction therapy can now be applied before surgery in patients with tumours considered inoperable, improving resectability and outcome without adding morbidity and mortality to the surgical procedure. This newly developed approach helps to reduce the recurrence rate and to ameliorate disease-free survival. New therapies are now being evaluated as for many other tumours; however, they still need confirmation in prospective randomised studies. In the future, integrated treatment modality should be incorporated in a standardised approach that goes from a careful assessment of histology, staging and lymph node status, and a constructive and non-empirical co-operation between medical and radiation oncologists, pathologists and thoracic surgeons.

Thymic carcinoma patients with myasthenia gravis exhibit better prognoses

“…Thymic carcinoma is exceedingly rare, accounting for less than 10-20 % of all thymic tumors [10,15]. Although MG is not commonly observed in patients with thymic carcinoma, it can still be considered as a paraneoplastic Although the underlying mechanisms that link MG to a better prognosis are unclear, the following theories may contribute.…”

“…Current incidence rates vary from 9 to 21 per million, and prevalence rates are between 50 and 125 per million worldwide [13]. Approximately 10-12 % of patients with MG have thymomas, whereas 30 % of thymomas are accompanied by MG [14,15]. Few studies report the coexistence of MG and thymic carcinoma, however, and the reported incidence varies dramatically, from 3.8 % to 32.5 % [2,4,16,17].…”

Importance of Lymph Node Dissection in Thymic Carcinoma

“…The first and most important is the rarity of thymic carcinoma [2,14]. The uncommonness of the malignancy makes it difficult to collect sufficient data to analyze the outcomes of lymph node dissection and suggest appropriate treatment recommendations.…”

The role of Tc-99m-2-Methoxy-Isobutyl-Isonitrile Single Photon Emission Computed Tomography in visualizing anterior mediastinal tumor and differentiating histologic type of thymoma

“…The stage of thymic disease was classified according to the clinical and pathological classification by Masaoka et al as following: (stage I) encapsulated thymoma with no findings of microscopic or gross capsular invasion; (stage II) microscopic transcapsular invasion or gross tumor growth into the mediastinal fat or pleura; (stage III) invasion of pericardium, great vessels, or lung; (stage IVa) pleural or pericardial dissemination through direct extension or drop metastasis; and (stage IVb) lymphatic or hematogenous metastases [6]. For patients with surgical excision, the stage was determinated by operative and pathological findings.…”

“…However, the results of 18 FDG-PET imaging in thymic pathology are frequently conflicting [4][5][6][7], and it remains an expensive and complicated procedure, performed with tracers and imaging equipment available at a limited number of sites in Italy.…”