Locked hip joint: an uncommon presentation of localized pigmented villonodular synovitis.

We report a 24-year-old male who was admitted to the emergency department with an unusual complaint of locked hip joint. Magnetic resonance imaging (MRI) showed a 3-cm intra-articular synovial nodular mass and a 3.0x2.4x1.6-cm yellow-brownish colored pediculed synovial nodular mass was excised with hip arthroscopy. Pathological examination confirmed the diagnosis of pigmented villonodular synovitis. Excision of the mass allowed prompt resolution of the symptoms and there was no sign of recurrence at 3-year follow-up.