Suspicion of recurrent osteosarcoma in a patient with pseudotumour adjacent to the endoprosthesis
Marek Duczkowski1, Agnieszka Duczkowska1, Elżbieta Michalak2, Agnieszka Tomasik-Kowalska1, Sylwia Szkudlińska-Pawlak1, Bartosz Pachuta3, Anna Raciborska3, Monika Bekiesińska-Figatowska1
1 Department of Diagnostic Imaging, Institute of Mother and Child, Poland
2 Department of Pathomorphology, Institute of Mother and Child, Poland
3 Department of Oncology and Surgical Oncology for Children and Youth, Institute of Mother and Child, Poland
Correspondence: Agnieszka Duczkowska, Department of Diagnostic Imaging, Institute of Mother and Child, Kasprzaka 17a, 01-211, Warsaw, Poland; e-mail: email@example.com
Purpose: Pseudotumor is a rare complication after arthroplasty, most often of the hip joint, in response to metal particles present in the implant. There are merely sporadic reports of pseudotumor in patients with bone sarcoma after sparing surgery with endoprosthesis implant. The aim of this study is to present the characteristic imaging features of pseudotumor. Case report: We present a case of a 21-year-old male patient in whom a scheduled follow-up ultrasound revealed a painless lesion suspected of local recurrence at the border of the endoprosthesis and the bone stump 3.5 years after the end of treatment for osteosarcoma of the femur. Histopathology of the biopsy specimen revealed that the lesion was a pseudotumor. Conclusions: Although pseudotumor is sporadic in patients treated with endoprosthesis for bone sarcoma, their prolonged survival could bear the risk of such a complication. Imaging studies, in particular ultrasound, may be helpful in differentiating from local recurrence of sarcoma, however, the histopathology of the specimen obtained by open biopsy at a reference center is crucial for the final diagnosis.