Carcinoid tumorlets of the lung with metastasis to a peribronchial lymph node. Report of a case and review of the literature.

A case of a rare entity, pulmonary tumorlets that metastasized to a peribronchial lymph node, is reported. The patient, a 38-year-old man, underwent a right pneumonectomy for end-stage lung disease caused by bronchiectasis, chronic bronchitis, and pulmonary fibrosis. No tumors were detected on radiologic or on gross examination of the lung. Microscopically, multiple tumorlets were identified in the fibrotic pulmonary parenchyma. Five peribronchial lymph nodes were found and appeared grossly normal. A microscopic focus of metastatic tumor, histologically identical to the pulmonary tumorlets, was discovered in one of these nodes. This metastasis was identified only because a diligent search for peribronchial lymph nodes was undertaken, and because sections of each node were obtained. Pathologists usually do not extensively examine peribronchial lymph nodes in cases of chronic inflammatory disease of the lung, even when small tumorlets are discovered as incidental findings, because it is presumed that the tumorlets have not metastasized. As shown by our case, this presumption is not always correct. Pulmonary tumorlets may metastasize to peribronchial lymph nodes more frequently than has been previously recognized.