Coxalgie migrante révélant une leucémie rare chez un adolescent: à propos d’un cas

Objective : Differential diagnosis of persistent migrating hip pain in adolescents is wide. Furthermore, non-traumatic causes of hip pain may be revealed by a traumatic episode. Material / Patients and Methods : We report the case of a 16-year-old boy who developed right hip pain within few days following a bike fall. After one week, he presented to the emergency department with isolated pain at right hip flexion. Conventional radiography was normal. He was discharged with rest and non-steroidal anti-inflammatory drug. A pelvic MRI was performed six week after the fall. It revealed major edema of the femoral head and neck, with heterogeneous enhancement following gadolinium injection. Two weeks later, the patient presented to our consultation with a one-week progressive pain of the left hip. There was no right hip complaint anymore. The patient also reported increased fatigue. Physical examination was normal for the right hip, but revealed a severe, painful, limitation of the flexion and internal rotation of the left hip. Hip ultrasonography and fluoroscopy showed mild left hip effusion. Blood analysis revealed severe hyperleucocytosis, with normal formula. Results : A bone marrow biopsy revealed chronic myeloid leukemia with presence of clonal (9:22) translocation (Philadelphia chromosom). Imatinib, a tyrosine kinase inhibitor, was initiated after complete work-up. Hip pain subsequently disappeared and cytologic remission was rapidly achieved. The child is currently in maintenance therapy. Discussion - Conclusion : This case emphasizes the importance of considering (1) non-traumatic causes of pain in front of atypical post-traumatic pain (2) bone marrow infiltration when facing migrant or persistent inflammatory hip pain.