Primary neuroendocrine carcinoma of the thymus: A retrospective analysis from a regional cancer center in Western India

Primary neuroendocrine tumors of the thymus are unusual anterior mediastinal tumors with a variable prognosis. A retrospective analysis of five patients with primary neuroendocrine tumors of the thymus admitted to the Gujarat Cancer and Research Institute, Ahmedabad, between 2012 and 2016, was done to study the clinical profile and outcome of these patients. The role of various prognostic factors such as surgical resection, histological grade, and Masaoka-Koga staging was also analyzed. Majority of the patients present with signs and symptoms related to a rapidly expanding mediastinal mass, such as breathlessness, facial puffiness, edema over the neck and extremities, chest pain, and other features of superior vena cava (SVC) syndrome. Collateral venous dilatation over the neck and chest and edema over neck were the most common physical signs. All the patients enrolled in the study presented in advanced stages with a poor differentiation on histopathological examination. Thymic neuroendocrine tumors usually manifest as large, lobulated, and locally invasive anterior mediastinal masses surrounding the great vessels of the neck and thorax. None of the diagnosed patients underwent surgical resection in view of extensive vascular encasement in the neck and thorax, and all of them were started on platinum-based palliative chemotherapy. The median survival of the patients was 12 months with the longest survival of 16 months for one patient. Possibility of this potentially rare entity should be kept in mind when a patient presents with features of SVC syndrome and large mediastinal mass. Complete surgical resection of the tumor is prognostic of improved treatment outcome and long-term survival. Large tumor size could be a determinant of poor overall outcome, and tumor size should strongly be considered as a factor in the revised (NETT) Neuroendocrine tumours of thymus staging. Histological grade and Masaoka-Koga stage are the important prognostic factors, but this study emphasizes the utmost need to further validate the prognostic factors.