[Thymic carcinoma associated with pulmonary sarcoidosis]

A 54-year-old man who worked as a farmer was admitted to the hospital in August 1989 because of bilateral hilar adenopathy that was detected during a mass screening. Laboratory examination showed a high serum lysozyme level and the PPD skin test was negative. Examination of a specimen obtained by transbronchial lung biopsy revealed non-caseous epithelioid cell granuloma. Sarcoidosis was diagnosed. The patient was not treated, and the bilateral hilar adenopathy had lessened by 1992. The patient was readmitted to our hospital because of right hilar and upper mediastinal enlargement seen on a chest radiograph in April 1994. Computed tomography and magnet resonance imaging disclosed an anterior mediastinal tumor in contact with the right upper lobe, the left inominate vein, and the pericardium. Bronchoscopy showed no abnormality in the right upper-lobe bronchus. Examination of a specimen obtained from the B3b bronchus showed no evidence of malignant cells. Examination of a tumor specimen obtained by transdermal biopsy showed squamous cell carcinoma. After the patient underwent combination chemotherapy, the tumor ws resected, along with the right upper lobe, the left inominate vein, and the pericardium, which were difficult to separate from the tumor. Postoperative pathological examination showed that squamous cell carcinoma was intermingled with normal thymus tissue. We believe that squamous cell carcinoma originated in the thymus. Non-caseous epithelioid cell granulomas were also found in the resected right upper lobe and in a mediastinal lymph node. The patient was discharged after post-operative irradiation of the mediastinum. Thymic carcinoma is rare, and sarcoidosis in a patient with thymic carcinoma is very rare. T lymphocytes are very important in the pathogenesis of sarcoidosis, and the thymus is involved in the growth and differentiation of T lymphocytes. The occurrence of these two diseases in one patient is interesting, but the relationship is not clear.