Recurrent thymic carcinoid tumor in the pleural cavity. 2 cases of long-term survivors

Locally advanced primary mediastinal atypical carcinoid successfully resected after neoadjuvant treatment: A case report

Neuroendocrine tumors (NETs) are epithelial neoplasms with predominant neuroendocrine differentiation that arise in most organs of the body. Mediastinal NETs are very rare, and account for no more than 5% of all mediastinal tumors. R0 surgery represents the milestone of treatment. Here, we describe a case of a locally advanced primary atypical carcinoid of the mediastinum. This was initially considered inoperable due to infiltration of a great vessel and was successfully resected after neoadjuvant treatment as a result of very extensive surgery. Only through an accurate preoperative diagnosis and good radiological planning is it possible to obtain satisfactory oncological results.

Neuroendocrine tumors of the thymus

Primary neuroendocrine tumors of the thymus (NETTs) are rare and biologically very aggressive neoplasms, usually located in the anterior mediastinal space. They are more frequently observed in males, in their fourth/fifth decades of life. In 50% of cases, NETTs are associated with endocrinopaties [Cushing's syndrome, acromegaly or Multiple Endocrine Neoplasia-1 (MEN-1) syndrome]. NETTs very often present with invasion of the surrounding mediastinal anatomical structures. Surgery, even in advanced stages, is the mainstay of treatment: a compete resection through a median sternotomy or a combined access (sternotomy + thoracotomy) should be always attempted. Induction chemotherapy (± radiotherapy) is usually administered in advanced neoplasms, with the aim to achieve tumor shinkage, increasing, therefore, the chance to obtain a complete resection. Postoperative radiotherapy (± chemotherapy) is administered in case of invasive lesions, or incomplete resections. NETTs long-term outcome is poor, even in case of completely resected tumors, due to high risk of recurrence or distant metastases development. Prognosis mainly depends on tumor stage, invasivity, completeness of resection, possible association with endocrinopaties and recurrence/distant metastases development.

Neuroendocrine tumors of the thymus and mediastinum

Neuroendocrine tumors of the thymus (tNET) and mediastinum are very rare neoplasms with scarce available data. All subtypes [typical and atypical carcinoid tumors (TC and AC), large cell neuroendocrine and small cell carcinoma (SCC)] observed elsewhere in the body occur also in the mediastinum and show only few if any organ-specific morphological differences. Although all available data suggest that the broad principles that govern the biology (and hence) the classification of these tumors in general apply also to tNET, there are a few noteworthy peculiarities related e.g., to risk factors, relative frequency and also to molecular genetic features. In this review, we will briefly summarize current knowledge on tNET with a special emphasis on shared and private features in comparison e.g., with pulmonary NET, which have traditionally been regarded the next closely related NET group.