[Cardiac block caused by metastasis of lung adenocarcinoma to the bundle of His].
It is well known from autopsy series that metastatic tumors of the heart can be found in 1.5% to 21% of patients with malignancies and the incidence of cardiac metastases is showing a gradual increase in recent years. The most common cause of metastatic heart disease is bronchial carcinoma followed by carcinoma of the breast, pleural mesothelioma, malignant melanoma, leukemia and lymphoma, in decreasing order of frequency. However metastatic cancer to the heart is not commonly diagnosed prior to death. Atrial extension has been reported as a common route of local spread in patients with bronchial carcinoma, but cardiac conduction system invasion is infrequent. The purpose of this report is to describe an unusual case of pulmonary adenocarcinoma that presented with cardiac manifestations mimicking atrioventricular (AV) block. This AV block was corrected by pacemaker. Chest radiography and bidimensional echocardiography didn't visualize important lesions. The cardiac findings at autopsy were remarkable not only for the severity of epicardial, myocardial and endocardial involvement, but for the metastatic implants into the His bundle and for the elective and wide infiltration of bifurcating His bundle. On addition histological examination revealed neoplastic emboli in the myocardial lymphatics. No valvular involvement was noted. Technical annotation: histological examination of the conduction system of the heart has been carried out on serial sections with the technique devised by one of the present authors. Bichromic (hematoxylin-eosin) and trichromic (Heidenhain-azan) stainings have been routinely employed.
Instituto di Anatomia Patologica, Università degli Studi di Milano.
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D000230:Adenocarcinoma / Q000150:complications* / Q000473:pathology / Q000556:secondary*; D000368:Aged; D002036:Bundle of His; D006327:Heart Block / Q000209:etiology*; D006338:Heart Neoplasms / Q000150:complications* / Q000473:pathology / Q000556:secondary*; D006801:Humans; D008175:Lung Neoplasms / Q000473:pathology*; D008297:Male
Blocco cardiaco da metastasi di adenocarcinoma polmonare nel fascio di His.