Abstract
Pulmonary carcinoids are the type of thoracic malignant tumors classified as neuroendocrine tumors. Case 1 involved a 59-year-old woman with a nodular shadow in the left upper pulmonary field observed on chest radiography. Chest computed tomography (CT) scan revealed a nodule in the left upper lobe and a soft tissue tumor near the left third rib. Given her elevated plasma progastrin-releasing peptide (ProGRP) level, a CT-guided biopsy was performed, confirming a diagnosis of pulmonary carcinoid with solitary bone metastasis. She subsequently underwent partial resection of the left upper lobe and the rib tumor. Case 2 involved a 67-year-old woman referred to our hospital after a chest CT scan revealed a nodule in the left lingular region. Her plasma ProGRP level was elevated, and a CT-guided biopsy confirmed a diagnosis of pulmonary carcinoid. As no lymph node metastases were detected, she underwent segmental resection of the left upper lobe. In both cases, plasma ProGRP levels decreased following surgical resection. These findings suggest that plasma ProGRP levels may serve as a useful diagnostic marker for pulmonary carcinoids.