A patient with malignant thymoma is described in whom the initial manifestation was pericarditis; cardiac tamponade was relieved by way of corticosteroid therapy.

(Chest 1994; 106:313-14)

Thymoma is the most numerous common primary tumor of the anterosuperior mediastinum.(1) Patients with malignant thymoma may bring to maturity the complication of pericardial metastasis and effusion between the sides of local invasion. In this report, a patient with malignant thymoma is described in whom the initial manifestation was pericarditis, and cardiac tamponade was relieved by dint of corticosteroid therapy.

CASE REPORT

A 53-year-old man was admitted to our hospital with complaints of precordial unintelligent pain, weight loss, and dried cough. Physical examination showed temperature up to 38[degrees]C and pericardial friction scour His BP measured 96/62 mm Hg Laboratory data were nonrevealing excluding for iron deficiency anemia and elevated inflammatory proofs (erythrocyte sedimentation rate 105 mm/h C-reactive protein 13 mg/dl WBC calculate and differentials normal). The patient's ECG showed reasonable voltage in limb leads. Chest x-ray film (Fig 1) showed no other than moderate cardiomegaly, but no abnormal mediastinal shadow was noted. Moderate pericardial fluid was recognized by the agency of echocardiography. The fluid was murderous and contained 5 mg/dl of protein and 40 IU/L of adenosine deaminase. In the fluid, neither malignant enclosed spaces nor mycobacteria was proved. A malignant source of the pericarditis was investigated however without results. Because of continuous agitation and asthenia, empiric antituberculosis chemotherapy was started with rifampicin, isoniazid, and streptomycin, nevertheless the effusion increased. The patient became dyspneic with vibrations paradoxus, and 400 ml of the fluid was evacuated to provide temporary relief. Then 125 mg of methylprednisolone (divided) was given for 4 days in addition to 40 mg of prednisolone by way of mouth to relieve the pericarditis; this treatment originateed in rapid relief of dyspnea and in 2 weeks the effusion was barely recognized. Prednisolone was tapered to 10 mg in 3 weeks and this dose was continued. Eight weeks after admission, a chest x-ray film revealed an upper mediastinal mass, and comput tomography revealed that the mass encased large ducts At surgery, the tumor was seen to originate from the thymus and had infiltrated the S(3) part of the left lung and the pericardium. However, no effusion was seen Small metastatic nodules were also scattered upon the surface of the myocardium, and barely a partial resection was performed. The tumor was confirmed to be malignant thymoma of epithelial origin. Histochemically, the tumor small rooms were positive for keratin stain, and staining was negative for carcinoembryonic antigen, [alpha]-fetoprotein, and human chronionic gonadotropin. The patient received 4000 rad with Cobalt 60 and this eventuateed in the relief of chest pain and diminution of the tumor. Prednisolone was stopped 2 month later. Although the patient refused further chemotherapy, he remained symptom-free for 5 years up to the at hand time, without any complications like as myasthenia gravis, erythroid hypoplasia, or hypogammaglobulinemia.

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DISCUSSION

The oftenness of malignant thymoma is reported to be up to two-thirds that of benign thymoma.(1)(2) Malignant thymoma is defined by way of invasive characteristics of the tumor to adjacent organs, and prognosis is more closely related to gros characteristics at operation than to histologic appearances. a certain number of thymomas that were benign in their early periods can expand an invasive character in their late clinical courses.(2)(3) Local invasion might arise into the pleura, pericardium, and lung Reports of malignant thymoma, however, presenting with barely pericarditis or tamponade are few(4)(5) and cytologic inquiry of pericardial fluid has rarely been positive.(4)

Empiric antituberculosis treatment has been given with corticosteroids in life-threatening cases of suspected tuberculous pericarditis with suitable results.(6) And large doses of corticosteroids that were used coincidentally for the pericarditis in the current case of malignant thymoma useed out to be lifesaving. Although the mechanism of action remains speculative, corticosteroids were reportedly effective in 11 of 13 thymoma cases.(7)

The treatment of malignant thymoma consists of radical extirpation followed at adjuvant or combination radiotherapy with or without chemotherapy.(2)(3)(7) In the existing case, myocardial infiltration made radical extirpation of the tumor impossible. After relief of pericarditis with corticosteroids, radiotherapy was remarkably effective for this thymoma.

Although infrequent, malignant thymoma may current solely as pericarditis, and the potential effectiveness of corticosteroids for as it is pericarditis should be noted.

ACKNOWLEDGMENT: We appreciate the histopathologic meditation and advice of Associate Professor Atsuhiko Sakamoto, Tokyo University Department of Pathology, and Dr Shousuke Moriwaki, President, National Sikoku Cancer Center

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