Carcinoid tumors are uncommon neuroendocrine malignancies representing 1-2% of all lung neoplasms, and present as solitary pulmonary nodules (SPN) only 20% of the time. FDG-PET is sensitive for detection of neoplastic SPN’s. However, previous reports suggest the hypometabolic growth of carcinoid neoplasms renders FDG-PET ineffective for their detection. Because of the rarity of carcinoid neoplasms, these conclusions are based on individual case reports and small reviews, which include carcinoids presenting as endobronchial lesions and pulmonary masses. Our purpose was to study the utility of FDG-PET in the evaluation of carcinoid neoplasms presenting as SPN’s.
Retrospective review of Mayo Clinic Rochester surgical pathology database from 5/00 to 3/03 revealed 98 patients with thoracic surgical resection of pathology proven typical or atypical carcinoid. Exclusion of patients with endobronchial lesions or pulmonary masses (tumor > 3cm) revealed 8 with a preceding FDG-PET study for evaluation of a pulmonary nodule. We reviewed these patients for FDG-PET result (+ or –) and Standardized Uptake Value (SUV), gross pathological size of the nodule, and tumor type.
Pathology showed 5 typical and 3 atypical carcinoids with average gross pathologic size of 1.43 cm (range, 0.8 – 2.0 cm). Overall PET sensitivity for detection of carcinoid tumors presenting as pulmonary nodules was 87.5% (7 true positives and 1false negative) with average SUV of 4.8 (range, 1.4 – 10.0). The one PET false negative carcinoid was a 1.3 cm, atypical carcinoid, with an SUV of 1.4.CONCLUSIONS: FDG-PET imaging is effective in detection of typical and atypical carcinoids presenting as SPNs. The sensitivity we report is higher than in previous studies and represents the largest series to date for FDG-PET evaluation of carcinoids presenting as pulmonary nodules.
FDG-PET imaging is effective for evaluation of suspected malignant pulmonary nodules including typical and atypical carcinoid
C.E. Daniels, None.