Clinicopathological analysis and outcome of primary mediastinal malignancies - A report of 91 cases from a single institute.

Background: Primary mediastinal malignancies are uncommon. They can originate from any mediastinal organ or tissue but most commonly arise from thymic, neurogenic, lymphatic, germinal or mesenchymal tissues.

Objectives: The aim of this study was to review the clinical presentations, diagnostic methods adopted, the histologies and the treatment outcomes of this rare subset of tumors.

Materials And Methods: Case records of 91 patients in the period 1993-2006 at our institute were retrospectively analyzed. Patients with primary mediastinal mass and supraclavicular nodes were included for the analysis. Patients with primary, extrathoracic disease of the lung and peripheral adenopathy were excluded. Actuarial method was used for calculating the disease-free survival and overall survival.

Results: Primary mediastinal tumors were seen commonly in males with mean age of 37.48 ± 17.04 years. As many as 97% of patients were symptomatic at presentation. Superior venacaval obstruction (SVCO) was seen in 28% of the patients. As many as 50% of the patients were diagnosed by a fine-needle aspiration or Trucut biopsy, while 28% of the patients required thoracotomy for a diagnosis. Majority of the tumors had anterior mediastinal presentation. Pleural effusion was seen in 20% of the patients, but diagnosis was obtained in only 1%. In adults, thymoma (39%), lymphoma (30%) and germ cell tumor (15%) were the common tumors. In the pediatric population, lymphoma, PNET and neuroblastoma were the common tumors. The 5-year DFS and OS are 50% and 55%, respectively.

Conclusion: Primary mediastinal tumors are a challenge to the treating physician because of their unique presentation in the form of medical emergencies, like superior venacaval obstruction and stridor. Diagnosis may require invasive procedures like thoracotomy. Treatment and outcome depend on the histologic subtypes.