title: Adult acute precursor B-cell lymphoblastic leukemia presenting as hypercalcemia and osteolytic bone lesions.
abstract: BACKGROUND
  Osteolytic bone lesions and hypercalcemia without peripheral blasts B-cell acute lymphoblastic leukemia (B-ALL) is reported in children but rarely seen in adults.
  
  
  METHODS
  We describe the case of a 34-year old man presenting with hypercalcemia and symptomatic osteolytic bone lesions of vertebrae and ribs who was initially suspected as having a solid malignancy. Diagnostic work-up including peripheral blood examination, radiographic and nuclear studies could, however, not detect a primary tumor. Because of a mild thrombocytopenia and the lack of a primary focus, a bone marrow biopsy was performed leading to the diagnosis of Philadelphia chromosome positive precursor B-ALL. After correction of the hypercalcemia with intravenous fluid administration, corticoids and bisphosphonates, the patient was treated according to the HOVON 100 protocol achieving complete molecular remission after the first cycle of induction chemotherapy.
  
  
  CONCLUSIONS
  Hypercalcemia and osteolytic bone lesions are rare complications of adult B-ALL and can occur in the absence of peripheral blastosis. With this case report we would like to emphasize the importance of clinical awareness. Immediate treatment of hypercalcemia and initiation of antileukemic treatment is mandatory as a delay of diagnosis might pose a real and possible life-threatening risk in these patients.
authors.affiliation: Division of Hematology, Antwerp University Hospital, Wilrijkstraat 10, 2650 Edegem, Belgium.
authors.forename: Nikki Charlotta Paul
authors.initials: NCP
authors.lastname: Granacher
authors.affiliation: Division of Hematology, Antwerp University Hospital, Wilrijkstraat 10, 2650 Edegem, Belgium.
authors.forename: Zwi N
authors.initials: ZN
authors.lastname: Berneman
authors.affiliation: Division of Hematology, Antwerp University Hospital, Wilrijkstraat 10, 2650 Edegem, Belgium.
authors.forename: Wilfried
authors.initials: W
authors.lastname: Schroyens
authors.affiliation: Division of Hematology, Antwerp University Hospital, Wilrijkstraat 10, 2650 Edegem, Belgium.
authors.forename: Ann L R
authors.initials: ALR
authors.lastname: Van de Velde
authors.affiliation: Division of Hematology, Antwerp University Hospital, Wilrijkstraat 10, 2650 Edegem, Belgium.
authors.forename: Anke
authors.initials: A
authors.lastname: Verlinden
authors.affiliation: Division of Hematology, Antwerp University Hospital, Wilrijkstraat 10, 2650 Edegem, Belgium.
authors.forename: Alain P A
authors.initials: APA
authors.lastname: Gadisseur
keywords: Adult precursor B-cell lymphoblastic leukemia; Case report; Hypercalcemia; Osteolysis; Philadelphia chromosome