A case of co-existing pigmented villonodular synovitis and tuberculosis infection of the foot and ankle.

A woman presented with chronic left ankle pain and swelling with no systemic upset. Magnetic resonance imaging suggested pigmented villonodular synovitis (PVNS) of her left ankle joint and flexor hallucis longus tendon. Combined arthroscopic and open synovectomy was performed. Histological examination of the synovium confirmed the diagnosis of PVNS, but culture of the diseased synovium yielded mycobacterium tuberculosis. This case illustrates the possibility of double pathology and the importance in excluding tuberculosis infection.