Pulmonary tuberculoma evaluated by means of FDG PET: Findings in 10 cases

PURPOSE: To describe findings of pulmonary tuberculoma at 2-[fluorine 18]fl uoro-2-deoxy-D-glucose (FDG) positron emission tomography (PET). MATERIALS AND METHODS: Ten consecutive patients who underwent PET and subse quently were proved to have pulmonary tuberculoma were analyzed. Tuberculos is was proved histopathologically in eight by means of wedge resection or l obectomy (n = 7) or needle biopsy (n = 1) and in two by means of clinical f ollow-up for more than 2 years. PET scans were evaluated by using peak stan dardized uptake values. Computed tomographic (CT) and histopathologic findi ngs also were reviewed. RESULTS: Nine of 10 tuberculomas showed FDC uptake at PET, and the mean pea k standardized uptake value was 4.2 +/- 2.2 (SD). FDC uptake (range, 1.9-3. 7) in lesions adjacent to main abnormalities was demonstrated in four patie nts. On CT scans, the mean of the longest nodule diameters was 21 mm +/- 8, and there were some areas of branching linear opacities or satellite nodul es that suggested pulmonary tuberculosis in seven patients. Histopathologic findings were chronic granulomatous inflammation with caseation necrosis ( n = 7) and healed tuberculosis with aspergilloma (n = 1). CONCLUSION: Pulmonary tuberculoma commonly causes an increase in FDC uptake . These results suggest that in geographic regions with a high prevalence o f granulomatous lesions, positive FDC PET results should be interpreted wit h caution in differentiating benign from malignant pulmonary abnormalities.