Differential diagnosis of pulmonary nodular mucinous adenocarcinoma and tuberculoma with dynamic CT: a retrospective study

BACKGROUND: Pulmonary nodular mucinous adenocarcinoma (PNMA) tends to be easily misdiagnosed as tuberculoma in practice. In this study, we aimed to discriminate PNMA from tuberculoma with dynamic computed tomography (CT). METHODS: In this study, 38 consecutive pathologically confirmed cases of PNMA and 23 cases of tuberculoma from January 2015 to December 2019 were retrospectively collected. The mean CT attenuations of each lesion were examined. The values on the plain scan, the venous scan, and the enhanced values (CT attenuation of lesion of venous scan minus that of the plain scan) were tested with an independent t-test pair-wisely. Receiver operating characteristic (ROC) curve analyses were performed to test the differential diagnosis values. The presence of satellite lesions was determined with the chi-square test. RESULTS: The mean CT attenuation of tuberculoma shown on the plain scan was significantly higher than that of PNMA (35.15±16.00 vs. 24.00±12.67 HU; P<0.01). The enhanced value of tuberculoma on venous scan was significantly lower than that of PNMA (13.44±13.40 vs. 22.52±14.00 HU; P=0.02). The optimum CT attenuation of the plain scan and the enhanced value for differential diagnosis were 28.80 and 14.25 HU [area under the curve (AUC) =0.72, 95% confidence interval (CI): 0.58–0.86; and AUC =0.70, 95% CI: 0.59–0.84], with sensitivity (78.3% vs. 71.1%) and specificity (63.8% vs. 69.6%) respectively. The satellite lesions were more often observed in the tuberculoma group (P<0.01). CONCLUSIONS: The CT attenuation of the plain scan, the enhanced value after enhancement, and the presence of satellite lesions might be useful in differentiating PNMA from tuberculoma.