Spontaneous regression of a carcinoid tumor that required resection owing to its reappearance and subsequent enlargement after 2 years: a case report.

We present a rare case of spontaneous regression in a typical lung carcinoid. A 20-year-old woman with an abnormal shadow on a chest radiograph was admitted to our hospital. Computed tomography revealed a smooth nodule in the left S1 + 2 segment. At the 6-month follow-up, the nodule had regressed without treatment. At the 2-year follow-up, the tumor reappeared in the same place as before. We performed left upper lobectomy via 4-port thoracoscopic surgery. A pathological examination revealed a typical carcinoid. Lung carcinoids can spontaneously regress; long-term follow-up is important for timely detection of tumor reappearance.