Intra-Articular Tenosynovial Giant Cell Tumor Mimicking Septic Arthritis: A Report of Two Cases.

Introduction: Intra-articular tenosynovial giant cell tumor (IATGCT) is a type of tenosynovial giant cell tumor that typically occurs in the synovial tissues of large joints. It is also known as pigmented villonodular synovitis. Acute onset of the pain with irritable hip symptoms is very rare. In this paper, we presented two adolescents with acute onset of hip pain mimicking septic arthritis diagnosed with intra-articular tenosynovial giant cell tumor. Case Report: Healthy two adolescents, one male (14-year-old) and the other girl (15-year-old) with no history of the previous trauma or significant comorbidities were presented complaining of acute onset of hip pain to our emergency room. Although initial possible diagnosis was septic arthritis for both cases, laboratory findings were unequivocal for septic arthritis and magnetic resonance imaging (MRI) showed an intra-articular nodular mass. An open resection was performed and pathological evaluation revealed the masses to be intra-articular tenosynovial giant cell tumor. After 26 and 17 months follow-up there was no pain neither with activity nor in rest, hip range of motion was within normal ranges. There was no recurrence, avascular necrosis or destruction detected on control MRI for both patients. Conclusion: IATGCT is a rare disease of the pediatric population involving the hip. Inflammation or infarction of the lesion can trigger irritable hip findings in children. This diagnosis should be kept in mind mainly in cases with serohemorrhagic aspirate and unequivocal laboratory findings.