Tehran University of Medical Sciences International Journal of Hematology-Oncology and Stem Cell Research 2008-2207 8 2 2014 06 15 38 40 Gholamreza Bahoush Assistant professor of pediatric hematology-oncology, Oncopathology research center, Ali Asghar children's hospital, Iran University of medical sciences, Tehran, Iran. Ghasem Miri-Aliabad Assistant professor of pediatric hematology-oncology, Children and Adolescent Health Research Center, Zahedan University of Medical Sciences, Zahedan, Iran. 2015 10 14 Hypercalcemia in children is a medical emergency and often manifests as nonspecific symptoms such as nausea, vomiting, weight loss, and anorexia. Severe hypercalcemia is a rare complication of malignancy in children, while it can be seen in various types of malignant tumors. It is usually associated with significant morbidity and may be severe enough to threaten life. Incidence of hypercalcemia in hematopoietic malignancies including acute lymphoblastic leukemia (ALL) is very rare and unusual, especially as the initial manifestation of the disease. In this paper a 6-year-old boy who had severe hypercalcemia and gastrointestinal symptoms before the onset of common and usual manifestations of ALL is introduced. https://ijhoscr.tums.ac.ir/index.php/ijhoscr/article/view/421 https://ijhoscr.tums.ac.ir/index.php/ijhoscr/article/download/421/376