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Thymoma presenting as chest pain.

CLINICAL PRESENTATION A 75-year-old ex-smoker male with hypertension and diabetes presented to the emergency room with pressure-like, midsternal, nonradiating chest pain for 2 hours, not associated with dyspnea, diaphoresis, palpitations, fever and pleurisy. Electrocardiogram and cardiac enzymes were normal. Chest x-ray revealed a rounded mass along the left heart border (Figure 1A). A contrast-enhanced computed tomography scan of the chest defined it as a well-circumscribed, solid, lobulated anterior mediastinal mass measuring 6.2 [times] 5.3 [times] 9.5 cm consistent with thymoma (Figure 1B). Patient underwent a radical thymectomy that involved en-block resection of the tumor, 10.5 cm in greatest dimension, with adherent portion of the lung, mediastinal fat and portion of the pericardium (Figure 1C). Histopathology confirmed it as a Modified Masaoka Stage III, WHO Type A Thymoma with focal tumor extension into lung parenchyma and mediastinal fat (Figure 1D). Although tumor margins were uninvolved, the distance of tumor from the closest margin was only 0.5 mm. Therefore, the patient was referred to Radiation Oncology and was treated with 30 sessions of radiotherapy. After radiation therapy, the patient remains tumor-free and is being monitored at regular intervals for reoccurrence. Thymoma is a rare tumor. It originates within the epithelium of thymus and generally arises in the anterior mediastinum, where it represents 50% of all anterior mediastinal masses. Onethird to half of the patients are asymptomatic, one-third are diagnosed during a workup for myasthenia gravis and the remaining cases present with chest pain, cough, hoarseness, dysphagia or superior vena cava syndrome. Complete surgical resection, when feasible, is the preferred therapeutic modality. Chemotherapy and radiotherapy are used for patients with residual disease after resection or with histopathology revealing thymic carcinoma. Patients with locally advanced disease may undergo initial chemotherapy with re-evaluation for possible surgery afterward. Patients presenting with metastatic disease are treated with chemotherapy initially. Prognosis depends upon Masaoka Staging and WHO Histologic Classification. Surveillance is usually performed annually with computed tomography scan of the chest.