INTRODUCTION:Thymoma is a neoplasm, which is usually localized and cured by surgical resection. However metastatic disease from resected thymoma has been described. Late onset pleural metastasis as the sole manifestation of thymoma recurrence is rare.
CASE PRESENTATION:62 year old man with myasthenia gravis diagnosed 12 years ago being treated with pyridostigmine, immunosuppressants and steroids presented with a flu like illness. He had thymectomy 11 years ago for invasive thymoma and multiple admissions for pneumonia requiring mechanical ventilation in the last 10 years. His physical examination was unremarkable. Chest radiograph showed multiple large pleural based masses. CT chest revealed multiple pleural masses ranging in size from 2 to 7cm. A few of the nodules arouse from the fissures, diaphragmatic pleura and one from the anterior junctional line. A trans thoracic core biopsy revealed dense hyalinized tissue along with admixture of lymphocytes and epithelial cells with nuclear pleomorphism. Tumor cells were positive for MOC 31, P 63, A-3, which was indicative of thymoma.
DISCUSSIONS:Thymoma is the most common neoplasm of anterior mediastinum and is frequently associated with immunological disorders such as myasthenia gravis, pure red cell aplasia and hypogammaglobulinemia. It is a slow growing tumor and rarely produces distant metastasis and therefore surgery remains the main stay of treatment. However a small number of thymomas show invasive growth locally. Although thymomas have a favorable clinical course after complete resection, recurrences after several years have been reported. Pleural dissemination and extra thoracic metastasis have been described. Pleural metastatic involvement may present as unilateral pleural thickening, pleural masses, or diffuse nodular circumferential pleural thickening encasing the ipsilateral lung usually without pleural effusion as seen in our patient. WHO classified these tumors based on the histology. Type A tumors composed predominantly of spindle cells. Type AB tumors have mixed cellularity (both spindle and epithelioid cells). Type B tumors have predominantly epitheloid cells and are subdivided as B1 with cortical thymoma and abundant lymphocytes, B2 with predominant lymphocytes and epithelial cells with prominent nucleoli, and B3 tumors with predominant epithelial cells with mild atypia and few lymphocytes. Treatment of these recurrent thymomas include re-resection, if resectable.
CONCLUSION:Thymomas usually have a favorable outcome after complete resection, but late recurrences more than 10 years after surgery have been reported. Our patient’s presentation is unique in that the only recognizable evidence of recurrent thymoma 11 years after resection for cure was in the form of multiple pleural metastasis. Even in patients who are unresectable chemotherapy is a viable option.
DISCLOSURE:Hima Kona, No Financial Disclosure Information; No Product/Research Disclosure Information