Knee Tuberculosis Presenting As Pigmented villonodular Synovitis

INTRODUCTION: Extra pulmonary Tuberculosis (TB) May mimic other diseases in clinical presentation which might be difficult to differentiate and diagnose. Pigmented villonodular synovitis (PVNS) may closely resemble tuberculosis of the knee joint. In younger patients, without any other co-morbid conditions TB of knee joint and PVNS in the knee might present with involvement of the isolated joint, with swelling which is painful for long duration with restriction in the range of motion. Treatment of both the conditions differs vastly and delay in the treatment can result in permanent disfiguration of the joint. CASE REPORT: A male 35 years old having a right knee painful swelling since last 6 months. The thorough physical examination, radiographs, and MRI suggest PVNS but an altogether different diagnosis is made after confirmatory investigations, i.e. Histopathological examination. CONCLUSION: Clinical and radiological presentation of TB and PVNS can mimic each other . Therefore TB should be suspected specially in the like India (endemic). For confirmation of diagnosis hisptopathological and mycobacterial results are important.