[Atypical carcinoid of the lung with abnormal elevation of serum ProGRP level; report of a case].

We report a rare case of an atypical carcinoid of the lung with the elevation of serum ProGRP. A 79-year-old female was referred to our hospital presenting with an abnormal shadow by a chest X-ray film. Chest computed tomography (CT) scan revealed a well-defined solitary nodule in the left lower lobe. The serum level of ProGRP was elevated to 2.267 pg/ml (normal range: <46 pg/ml). Pulmonary carcinoid was pathologically suggested by a transbronchial lung biopsy. Considering the patient's general condition, a partial wide resection was performed. Pathological diagnosis was atypical carcinoid. After the operation, further increase of the serum ProGRP level was noted, and multiple liver metastases developed.