Intrapulmonary lymph nodes. Clinical, radiologic, and pathologic features.

The clinical, radiographic, and pathologic material from ten patients with intrapulmonary lymph nodes was analyzed, along with information from all previously reported cases. In our series the median age was 56 years, and 80 percent (eight) of the patients were men. All patients are or were cigarette smokers. Sixty percent (six) had a history of exposure to either asbestos, nonfibrous silicates, or both. There were no characteristic symptoms attributable to the intrapulmonary lymph nodes. Forty percent (four) had an unexplained pulmonary nodule or nodules on the chest roentgenogram, which prompted further diagnostic studies, including thoracotomy, to rule out a malignant neoplasm. Radiographically, in our cases and in the literature, almost all cases of intrapulmonary lymph nodes are subpleural, inferior to the level of the carina, and less than 2.0 cm in diameter. Thirty-five percent are multiple. Pathologically, in our cases, all intrapulmonary lymph nodes were markedly anthracotic, and 60 percent were additionally silicotic. Although their histogenesis is uncertain, intrapulmonary lymph nodes are probably hyperplastic lymphoid nodules related to inhalation of irritant dusts and attendant distortion of local lymphatic vessels. Precise clinical and radiographic analysis correlated carefully with cytologic and histologic material obtained by percutaneous needle biopsy should obviate exploratory thoracotomy in most instances.