Debut of childhood acute lymphoblastic leukemia with malignant hypercalcemia, unusual presentation: a case report

Abstract

Introduction. Leukaemia is the leading childhood cancer, with a 2022 incidence rate of 5.5 per 100,000 children. In the pediatric population, Hypercalcaemia maligna is one of its rare and severe paraneoplastic manifestations (overall incidence 0.4 - 1.3%). Objective. To present a case of acute lymphoblastic leukemia that debuted with severe hypercalcemia. Case description. It is about a 3-year-old female preschooler who started with a clinical picture characterized by bone pain and functional limitation; initial haemograms showed no alteration of cell lines, radiographs showed generalized osteopenia, accompanied by severe hypercalcemia, inhibited parathyroid hormone and secondary hypercalciuria, which were managed with intravenous hydration, diuretic, steroid and zoledronic acid. She also presented electrolyte imbalances that required potassium and phosphorus replacement with adequate response. Bone marrow studies were performed, confirming the diagnosis of acute lymphoblastic leukemia; she received ALLIC 2009 protocol chemotherapy with refractory disease at the end of the induction phase, and finally, a haploidentical bone marrow transplant, which was successful. Discussion. Hypercalcemia of malignancy is one of the endocrinological oncological emergencies with a low incidence, which is more frequent in the adult population. So, it is not the first diagnostic impression to be considered in pediatrics, leading to delays in aetiological diagnosis and prognosis. Conclusion. Hypercalcaemia accompanied by diffuse osteolytic lesions may be the first and only manifestation in the pediatric population with a diagnosis of acute lymphoblastic leukemia. Recognizing it will lead to the timely initiation of treatment, with an impact on survival.