Abstract： A 70-year-old woman was admitted for a 2-year-history,pruritic and erythematous patches on the chest and back.Skin examination showed large-sized,infiltrative and red-brown patches,papules,plaques,and some lesions were covered with blood crusts.Histopathologically,there were epithelioid histiocyte masses in the upper and middle dermis,lymphocytic infiltrate were observed around some masses.No fungus was found from clinical specimens by microscopy or culture.Biopsy specimens were positive for an 8-week mycobacterium culture and acid-fast bacilli,and the isolate was identified as Mycobacterium tuberculosis by PCR-restriction fragment length polymorphism(PCR-RFLP)analysis.The case was diagnosed as lupus planus according to clinical manifestation and laboratory tests.