Can Primary Knee Tuberculosis Simulate the Clinical and Radiological Profile of Pigmented Villonodular Synovitis?

When faced with clinical and radiological findings suggestive of villonodular synovitis, tuberculosis is not often considered a differential diagnosis, especially when the patient is not a known tuberculosis carrier. In this paper, we present an exceptional case of a patient who had a tumefaction (measuring 17 cm in length) in the anterointernal region of her left knee, with a clinical and radiological picture in favor of villonodular synovitis. However, after tumor resection, the anatomopathological study of the surgical specimen came back in favor of a tuberculous lesion. This exceptional case shows that tuberculosis should be retained as a diagnostic possibility in the presence of clinical and radiological findings in favor of villonodular synovitis, even if the patient is not known to have a tuberculous lesion elsewhere.