Subacute (giant cell) thyroiditis and giant cell myocarditis in patient with carcinoma of lung

Subacute (giant cell) thyroiditis most probably represents a viral disease. Its coexistence with giant cell myocarditis, the etiology of which is unknown, in a patient with carcinoma of the lung is described. It is suggested that in this instance both the thyroiditis and myocarditis may be due to viral infection. The possible rule of autoimmunity in the development of the cardiac lesions is discussed.