Bisphosphonate treatment of tumor-induced hypercalcemia in a toddler: case report and review of related literature

Abstract

Objective: To describe the initial manifestations and treatment of parathyroid hormone-related peptide (PTH-rP)-induced hypercalcemia in a toddler with a malignant rhabdoid tumor.

Methods: We report a case of a 2-year-old boy presenting with poor appetite, lethargy, and a 1.5-kg weight loss during a 2-week period. On examination, the child was found to have a right upper quadrant abdominal mass. Laboratory studies revealed severe hypercalcemia. We review the patients' clinical course and management of hypercalcemia.

Results: Initial evaluation revealed no cardiovascular instability. An abdominal mass was identified on physical examination. Initial laboratory studies revealed elevated levels of total and ionized calcium, low phosphorus, microcytic anemia, and elevated erythrocyte sedimentation rate. Saline diuresis with furosemide was begun. Abdominal ultrasonography revealed a large right renal tumor. Because of refractory hypercalcemia, intravenously administered bisphosphonate was used. Within 12 hours after bisphosphonate infusion, the serum calcium level declined from 14.9 mg/dL to 10.9 mg/dL. The furosemide dose was decreased and finally discontinued 2 days after bisphosphonate administration. Because of development of a femoral thrombosis, definitive surgical intervention was delayed. During that time, serum calcium levels again increased and necessitated administration of a second bisphosphonate dose. At surgical treatment, a right renal tumor was identified, and frozen section pathology revealed a rhabdoid tumor. After tumor resection, calcium levels were stable. Other laboratory studies performed at admission revealed suppressed PTH, normal vitamin D and calcitonin levels, and elevated PTH-rP.

Conclusion: Hypercalcemia in a toddler is a rare event and can be attributable to humoral factors released by malignant tumors. Hypercalcemia in the pediatric population can be treated effectively with bisphosphonates when conservative measures fail.