[Recurrence of chondroblastoma in the distal femur: a clinical case report]

Chondroblastoma is a benign bone tumor that arises from cartilaginous tissue in the long bones. It has a low incidence, and can be asymptomatic, or even presenting as a pathological bone fracture. The importance of diagnosis lies in extension, recurrence and risk of dissemination. Our objective is to show the evolution of a patient, who followed a favorable course after an episode of recurrence. A 15-year-old patient is presented who, after mild discomfort in her left knee for 6 months, suffered a level fall, with pain and functional impotence. X-rays and CT showed a fracture of the left distal femur, with an infiltrative lytic lesion in the distal epiphysis. Curettage was performed with local bone graft, open biopsy, electrofulguration, adjuvant therapy with alcohol and closure with osteoconductive matrix. The biopsy indicated a chondroblastoma without atypia, and the dissemination study was negative. She remained in periodic controls, and after 7 months an MRI was obtained with an image suggestive of recurrence in the adjacent metaphysis. A new curettage with biopsy was performed, which indicated a recurrence of chondroblastoma. Currently, she is being monitored, 5 years after the first intervention. In the last appointment, she reported anterior knee pain, without radiological signs of recurrence, which responded correctly to physical management, showing her complete current functional capacity, good exercise tolerance, and no limitations in daily life.