[A Case of Pulmonary Carcinoid That Has Regressed Spontaneously]

A 65-year-old woman who had diabetes mellitus was referred to the Department of Diabetes Internal Medicine of our hospital in June 201X due to disease progression. Chest radiography revealed an abnormal shadow, and computed tomography( CT)showed a 2 cm nodular shadow in the right S10. Lung cancer was suspected because of increased serum progastrin- releasing peptide(ProGRP)level and smoking history. She was referred to our department and was diagnosed with carcinoid on transbronchial biopsy. After 1 month, CT demonstrated regression of the carcinoid and improved serum ProGRP level. After more than 1 month, the carcinoid size did not change, and serum ProGRP level slightly increased. We expected that it would be difficult for the carcinoid to regress. After glycemic control was improved, the patient underwent right lower lobectomy via video-assisted thoracoscopy. In the resected specimen, the border of carcinoid was clear. She was diagnosed with a typical carcinoid. The carcinoid was not accompanied by inflammation or necrotic tissue. A carcinoid is a low-grade malignant tumor and does not usually regress spontaneously. However, in this case, it regressed spontaneously.