LAUSR

could be affected by other factors. Some elderly, weak, or immunosuppressive patients may have a false negative result. Inoculation with Bacillus Calmette-Gu Rin (BCG) can produce a false positive result; however, BCG is usually inoculated in childhood and its influence diminishes with time. In CTB patients, PPD can be from negative to different degrees of positive. Although it was impossible for the patient to recall the history of BCG vaccination, the results of PPD positive still indicate TB infection; (iv) It is difficult to find TB in the pathological section because of small number of active TBs, so other examinations and repeat biopsy may be necessary. Experimental anti-tuberculosis treatment is an important supplementary means for diagnosis of highly suspected patients. If there is no sign of improvement after 3 weeks of anti-tuberculosis drugs, TB infection should be excluded. The long-term misdiagnosis of the present case is due to lack of familiarity of CTB. We should realize that the incidence of CTB has been increasing in recent years, so we should pay more attention to this old but not obsolete disease.