Abstract: Objective  To raise the CT differential diagnosis level, comparative study CT imaging and clinic pathologic features in patients with atypical tuberculosis which were easily misdiagnosised as lung cancer. Methods  Retrospective studies 33 cases of atypical pulmonary tuberculosis patients (confirmed by pathology) were misdiagnosised as lung cancer by CT in Shanxi Tumor Hospital. Results  All the 33 focuses in 33 cases showed nodule or mass shadows，the diameter was around 0.9－5.7 cm， average value was（3.04±0.15）cm. Focuses of 25 cases were occurred at double upper lobe of lung and double lung dorsal segment of lower lobe. There were 7 cases with cavity in focuses interior(21.2%,7/33)，10 cases with calcification(30.3%,10/33). There were marginal spiculated sign in 8 cases(24.2%,8/33) and long streaks in 10 cases(30.3%,10/33). Eight cases were with the same lung field with satellite nodules(24.2%,8/33)，4 cases were with calcification and granular in other lung field(12.1%,4/33).One case was pleural effusion. CT appearance with enhancement scan: 28 cases with enhancement，there were inhomogeneous enhancement 35.7%(10/28)，honeycomb enhancement 32.1%(9/28). Seventeen cases with CT plain and enhancement scan，the results showed CT value of enhancement part can be increase 7-58HU, ave-rage（24.1±1.8）HU. Conclusion  The CT appearance and clinical characteristics of atypical pulmonary tuberculosis were multiform，such as honeycomb enhancement， long streaks and satellite nodules， which can help distinguish atypical pulmonary tuberculosis from lung cancer.

Key words: Tuberculosis pulmonary/radiography, Tomography, X-ray computed