Benign subpleural lymph node appearing as a pulmonary "coin" lesion.

Abstract

A peripheral, pulmonary lymph node large enough to appear on chest roentgenograms as a coin lesion is unique. The pulmonary lymph nodes are situated in the parenchyma of the lung adjacent to the larger bronchi and tend to lie in the angles between the bronchial branches, usually extending only as far peripherally as the third bronchial branching. Most lymph tissues found beyond this point consist simply of aggregations of lymphoid cells and can not be regarded as normally occurring structures or true lymph nodes. They are generally caused by a response of the lymphoid tissue to infections, inhalation of irritating substances, or other noxious stimuli (1, 2). Miller, in his text on The Lung, (1) noted a definite increase in the pulmonary lymphoid tissue of older persons and attributed much of this increase to prior inhalation of carbon or other irritating particles rather than to past infections. The hyperplastic subpleural lymph node in the following case probably represents such a lymphatic response to the inhalation of anthracotic particles. This benign peripheral node appeared on the scout chest roentgenograms as a noncalcified, noncavitary, solitary pulmonary nodule. Case Report Mr. S. A., a well developed 58-year-old office worker, was hospitalized on Dec. 10, 1959, because of persistent epistaxis following an upper respiratory tract infection. Hemostasis was obtained by the insertion of anterior and posterior nasal packs, and the bleeding did not recur. Chest roentgenograms made on admission (Fig. 1) revealed a discrete, circumscribed area of increased density, 1.2 cm. in diameter, without calcification or cavitation, situated in the lateral basal segment of the lower lobe of the right lung. There was a calcific infiltrate in the right upper lobe. The patient gave a history of a chronic nonproductive cough often interrupting his sleep. He stated that he habitually smoked one and one-half packs of cigarettes daily. Physical examination of the chest was negative. There was slight digital clubbing. Intradermal tests with blastomycin and coccidioidin antigens and sputum examinations and cultures for M. tuberculosis were negative. A surgical consultation was obtained and a thoracotomy was recommended. It was subsequently performed without difficulty. A sharply defined, apparently encapsulated tumor, 1.2 cm. in diameter, was resected. Microscopic examination showed the subpleural mass to be a well circumscribed, hyperplastic lymph node with a rim of cortical follicles and a medullary portion containing a large amount of carbon pigment (Fig. 2). Comment In this patient the peripheral, pulmonary lymph node probably became hyperplastic in response to the presence of anthracotic particles. The hazard of carcinoma in the pulmonary coin lesion, particularly in men past the age of forty, has necessarily resulted in the resection of benign, asymptomatic lesions discovered on scout chest roentgenograms (3–5).