Pulmonary tumors of embryonic origin are rare, and pulmonary blastomas are probably the most uncommon. A thorough literature search disclosed no previous reports of extension of this type of tumor into the heart. We describe a patient whose initial clinical presentation suggested an obstructive left atrial mass; however, clinical and histologic findings indicated the mass was a tumor that origi-nated from a pulmonary blastoma that extended into the left atrium through a pulmonary vein. The unique aspect of this case is that the patient's symptoms were related to the obstructive effects of the atrial mass, not to the primary pulmonary tumor. Mayo Clin Proc. 2001;76:657-660A bout 10% of patients with malignant neoplasms have metastases to the heart. Of these patients, approximately 10% have clinical evidence of such metastases. Carcinomas invade the heart much more commonly than sarcomas. In up to 90% of patients with carcinomas, clinical findings are secondary to pericardial involvement, either effusion or pericardial thickening with restriction. 1 The only tumors not reported to metastasize to the heart are primary central nervous system neoplasms. In absolute numbers, the most common neoplasms that produce cardiac metatases are lung tumors in men and breast tumors in women, followed by leukemias and lymphomas in both sexes. The specific malignancy with the most frequent cardiac involvement is melanoma, which occurs in up to 70% of patients with disseminated disease. 2 The mechanism of metastatic growth to the heart depends on the tumor's origin and mode of spread. Lung and breast carcinomas tend to involve the heart and pericardium by direct extension from contiguous structures or from retrograde lymphatic spread. In some cases there is direct venous extension, such as renal and hepatic carcinomas that follow the inferior vena cava into the right atrium. Hematogenous spread is unusual for carcinomas, but it is the main route of cardiac metastasis for sarcomas, lymphomas, leukemias, and melanomas. 3 REPORT OF A CASEA 45-year-old man with a history of tobacco use presented to our emergency department because of a 3-week history of increasing dyspnea, orthopnea, and paroxysmal nocturnal dyspnea with progressively severe lower extremity edema. He denied having any previous serious medical problems.Review of symptoms disclosed a 2-month history of cough with white sputum when the patient was supine. On admission, he was normotensive, had hypoxemia with oxygen saturation of 88% while breathing room air, and had tachycardia at a rate of 123 beats/min. Physical examination showed a cachectic man with temporal wasting and slight tachypnea but in no acute distress. Jugular venous distention was noted. A lung examination revealed right basilar crackles, and the left lower lung was dull to percussion with decreased tactile fremitus and decreased breath sounds. Cardiac examination disclosed regular tachycardia with a positional mid diastolic click. Examination of the extremities showed 3+ pitting edema up to the knees bilate...

Pulmonary tumors of embryonic origin are rare, and pulmonary blastomas are probably the most uncommon. A thorough literature search disclosed no previous reports of extension of this type of tumor into the heart. We describe a patient whose initial clinical presentation suggested an obstructive left atrial mass; however, clinical and histologic findings indicated the mass was a tumor that originated from a pulmonary blastoma that extended into the left atrium through a pulmonary vein. The unique aspect of this case is that the patient's symptoms were related to the obstructive effects of the atrial mass, not to the primary pulmonary tumor.