Case: A 17-year-old boy presented to the clinic complaining of right hip pain after soccer participation. Clinical findings and imaging studies led to the diagnoses of femoroacetabular impingement and diffuse tenosynovial giant cell tumor (TGCT). Comprehensive arthroscopic management and biopsy revealed a diagnosis of osteosarcoma. The patient subsequently underwent chemotherapy, surgical resection, and reconstruction.
Conclusion: Osteosarcoma of the proximal femur may mimic TGCT on imaging studies because osteosarcoma may show changes suggestive of inflammation. We recommend heightened clinical awareness and a comprehensive differential workup in the management of presumed TGCT about the hip in the pediatric patient population.
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