[Three cases of small intrapulmonary lymph nodes coincidental with primary lung cancer]

We report three cases of intrapulmonary lymph nodes coincidental with primary lung cancers. In the first case, a 56-year-old man had a small subpleural nodule in the right lower lobe associated with adenocarcinoma of the right upper lobe. The small nodule was 10 mm in diameter and was difficult to differentiate radiologically from intrapulmonary metastasis. Wedge resection of this small nodule was performed. Histologic examination of the nodule revealed an intrapulmonary lymph node with anthracotic pigmentation. A right upper lobectomy for adenocarcinoma was performed, and was completely curative. The second patient, a 77-year-old woman, had adenocarcinoma in the right lower lobe diagnosed by transbronchial biopsy. Computed tomography (CT) revealed a small nodule 5 mm in diameter in the right upper lobe. Histologic examination of the small wedge-resected nodule revealed a lymph node. Lower lobectomy was performed with completely curative results. In the third case, a 63-year-old man was admitted for investigation of a mass shadow in the right upper lobe. CT showed a small nodular shadow in the right middle lobe, confirmed histologically to be lymphoid tissue, in addition to the original mass, which was diagnosed by transbronchial biopsy as squamous cell carcinoma. Upper lobectomy was performed and proved to be curative. Small intrapulmonary lymph nodes are very difficult to diagnose by methods other than surgical resection. When a small intrapulmonary nodule is detected in a patient with primary lung cancer, the presence of an intrapulmonary lymph node must be considered. If radiological characters compatible with an intrapulmonary lymph node are found and there is no other metastasis indicating poor prognosis, it should be considered as a possible indication for surgical resection.