Résumé
Granuloma Annulare [GA] is a granulomatous inflammatory lesion with unknown etiology. The etiologic relation between this disease and mycobacterium is still controversial. In this descriptive-Cross sectional study, specimens of GA have been assessed for mycobacterium infection. Paraffin embedded specimens of GA from archive of Pathology department of Emam Reza hospital, during 2001 to 2005, have been selected Multiplex PCR were done on them, with primers of 162bp and 123bp for mycobacterium in general and tuberculosis respectively. A total of 38 cases [31 female and 7 male] with the mean age of 42 years were found. The lesions were most commonly on upper extremities and the most common histological feature was lymphohistiocytic granulomatous inflammation of interstitial type [incomplete form of GA]. With Zeil Nelson staining all cases were negative for acid fast bacilli. PCR In one case detected amplification of both 123 bp and 162 bp segments which were compatible with M. tuberculosis infection. This case had extensive lesions all over the upper extremities and back of the trunk and in histology it had a lot of giant cells which is not a usual finding in GA. Mycobacterium may cause some types of GA lesions