Pediatric acute promyelocytic leukemia and Fanconi anemia: Case report and literature review.

Acute promyelocytic leukemia (APL) represents 5%-10% of childhood acute myeloid leukemia (AML) and is the most curable subtype of AML. Fanconi anemia (FA) is one of the most common inherited bone marrow failure syndromes caused by biallelic pathogenic variants (PV) in specific DNA-repair genes. Biallelic PVs in FANCD1/BRCA2 (FA-D1) account for 3% of FA and are associated with early-onset leukemia and a high risk of solid tumors. We report a 4 year-old boy from non-consanguineous parents diagnosed with standard risk APL. This child had café-au-lait spots and an extra thumb remnant. Genomic sequencing revealed two PV in FANCD1/BRCA2 confirming a diagnosis of FA-D1. Chromosomal breakage studies were compatible with FA. Each parent carried one variant and had no personal history of cancer. Morphological then molecular remissions were achieved with all-trans retinoic acid and Arsenic trioxide. This patient underwent haploidentical stem cell transplant. In addition to our patient, a literature search revealed four additional patients with APL/FA, with a total of three patients with FA-D1. This raises the possibility of an association between such rare disorders. Practical management of APL in the setting of FA-D1 is discussed with an overview of current evidence and knowledge gaps.

Case Report of Renal Calculi in a Child Receiving Imatinib for Acute Lymphoblastic Leukemia.

Rationale: Imatinib is used in the treatment of Philadelphia chromosome positive (Ph+) leukemias and has been reported to have a direct effect on bone physiology. Presentation: To report on a child with Ph+ acute lymphoblastic leukemia who presented with bilateral flank pain and gross hematuria. Diagnosis: She was diagnosed with obstructive kidney stones 101 days after commencing daily oral imatinib. Stone analysis revealed the presence of calcium phosphate. Interventions and outcome: The patient passed the stones spontaneously with medical therapy that included the use of thiazide, allopurinol, and potassium citrate, but she required temporary insertion of a double-J stent to relieve an obstruction. Novel findings: Imatinib inhibits receptor tyrosine kinases and stimulates the flux of calcium from the extracellular fluid into bone, resulting in hypocalcemia with a compensatory rise in parathyroid hormone that may result in phosphaturia and the formation of calcium phosphate stones. Given that kidney stones are rare events in children, we believe that monitoring for kidney stone formation needs to be performed in children receiving imatinib.

Justification: L'imatinib est utilisé dans le traitement des leucémies à chromosome Philadelphie (Ph+) et a été décrit comme ayant un effet direct sur la physiologie osseuse. Présentation du cas: Une enfant atteinte d'une leucémie lymphoblastique aiguë à Ph+ présentant des douleurs lombaires bilatérales et une hématurie macroscopique. Diagnostic: La patiente a reçu un diagnostic de calculs rénaux obstructifs 101 jours après avoir commencé la prise quotidienne d'imatinib par voie orale. L'analyse des calculs a révélé la présence de phosphate de calcium. Interventions et résultats: La patiente a éliminé spontanément ses calculs grâce à un traitement médical qui comprenait un diurétique thiazidique, de l'allopurinol et du citrate de potassium, mais on a dû lui insérer temporairement une endoprothèse double J pour traiter une obstruction. Nouveaux enseignements: L'imatinib inhibe les récepteurs de la tyrosine kinase et favorise le flux du calcium du liquide extracellulaire vers les os, ce qui entraîne une hypocalcémie avec élévation secondaire de l'hormone parathyroïdienne pouvant provoquer une phosphaturie et la formation de calculs de phosphate de calcium. Puisque la formation de calculs rénaux est rare chez les enfants, nous pensons qu'elle devrait faire l'objet d'une surveillance chez les enfants qui reçoivent de l'imatinib.