The utility of fluorodeoxyglucose positron emission tomography in the evaluation of carcinoid tumors presenting as pulmonary nodules.

BACKGROUND: Fluorodeoxyglucose positron emission tomography (FDG-PET) is sensitive for detection of neoplastic solitary pulmonary nodules but may have decreased sensitivity for detection of carcinoid tumors. Our purpose was to determine the sensitivity of FDG-PET to detect pulmonary carcinoid tumors.

METHODS: We performed a retrospective review of our institutional results regarding FDG-PET in the setting of thoracic carcinoid neoplasms. We identified 16 patients with a pathologic diagnosis of bronchial carcinoid who had an antecedent FDG-PET (from 2000 to 2004). All patients but one presented with pulmonary nodule(s).

RESULTS: Sixteen patients had a diagnosis of carcinoid tumor, typical in 11 patients and atypical in 5 patients. The mean greatest pathologic dimension was 2.08 cm (range, 1.0 to 8.3 cm). Overall positron emission tomography (PET) sensitivity was 75% (12 true-positive and 4 false-negative results). The mean (+/- SD) size of carcinoids with false-negative PET results was not significantly different from carcinoids with true-positive results (1.6 +/- 0.81 cm and 2.35 +/- 1.87 cm, p = 0.54). Fifteen of 16 patients were staged pathologically, and positive nodes were found in 2 of these patients. PET lymph node staging agreed with pathologic staging in one stage 4 patient with positive lymph nodes and distant metastasis, but PET results were false negative in the other patient who had N2 with micrometastatic disease; stage IIIA.

CONCLUSIONS: FDG-PET imaging is useful for evaluation of typical and atypical thoracic carcinoid tumors. Although overall PET sensitivity for detection of carcinoid tumors is somewhat reduced as compared to non-small cell lung cancer, it is much higher than prior reports suggest.