Background. Osteonecrosis (ON) is a long-known complication of acute leukemia (AL) management affecting 1 to 10% of young patients, leading to long-term morbidity. Widespread access to Magnetic Resonance Imagery (MRI) over the past ten years has allowed earlier detection and more accurate assessment. This study investigated clinical and radiological features of ON, among the large French cohort L.E.A (Leucémie Enfant Adolescent) Procedure. Patients with ON were retrospectively enrolled and risk factors for the onset, the multifocal involvement and severe damage were analyzed. Quality of life (QoL) was also evaluated. A sub-study described radiological features. Results. 129/4973 patients developed ON (2.5%) and were preferentially aged over 10 years at time of AL diagnosis (OR 22.46, p <10-6). Females were preferentially affected (OR 1.8, p=0.002) like patients treated for relapse (OR 1.81, p=0.041). Patients presenting ON suffered more frequently from other sequelae (p<10-6). Most of the necrosis were involving weight-bearing joints and multiple joints in 69% of cases. MRI of 39 patients with ON were double blinded reviewed. Overall, 14/39 suffered from severe impairment, preferentially on hips. QoL of adolescents and adults was poor and permanently affected once ON occurred. Conclusions. Age of over 10 years at diagnosis of AL, relapse and female sex were at risk of developing ON involving preferentially multiple joints. One third was severe and lasting poor QoL impacting several domains was found. Future studies should include prospective data on management and biological genetic features to build a targeted screening program to detect and manage ON earlier.

Introduction: Data regarding coronavirus disease 2019 (COVID-19) description are still limited in pediatric oncology. The French society of pediatric oncology (SFCE) has initiated a study to better describe the presentation and evolution of COVID-19 in patients followed in French pediatric oncology and hematology wards. Methods: All patients diagnosed with COVID-19 (polymerase chain reaction [PCR] positive for severe acute respiratory syndrome coronavirus 2 [SARS-CoV-2], or positive IgM serology, or chest computed tomography scan and clinical signs typical of COVID-19) and followed in a SFCE center were enrolled. Data from medical records were analyzed for all patients enrolled up to the end of May 2020. Results: Data was available for 37 patients. Thirty-one were children under 18 years of age. Nineteen patients were female. Seventeen patients had a solid tumor, 16 had a hematological malignancy and four recently underwent hematopoietic stem cell transplantation (HSCT) for non-oncological conditions. Twenty-eight patients presented symptoms, most often with fever, cough, rhinorrhea and asthenia. Ground-glass opacities were the most frequent radiological finding with abnormalities mostly bilateral and peripherally distributed. Twenty-four patients received chemotherapy a month prior to COVID-19 diagnosis. Most patients did not require hospitalization. Three patients required oxygen at the time of diagnosis. In total, five patients were admitted in an intensive care unit because of COVID-19 and one died from the disease. Conclusion: Children and young adults infected with SARS-CoV-2 and treated for a cancer and/or with a HSCT may be at risk for severe COVID-19 and should be closely monitored. (NCT04433871)

Pediatric cases represent a small part of COVID-19 cases reported worldwide and children seem to be mostly asymptomatic. The specific risks for patients in pediatric oncology wards are not well known yet. We describe here a pediatric hematopoietic stem cell transplant recipient infected by SARS-CoV-2. Despite being at high potential risk of a severe form of COVID-19 the patient we report only presented a rhinitis. She developed anti-SARS-CoV-2 IgM at D14 and IgG at D56 only and had a positive RT-PCR after 42 days. So far, it seems that in this fragile population COVID-19 is largely pauci-symptomatic.