Ectopic parathyroid hormone-producing cervical cancer requiring hemodialysis owing to acute hypercalcemia: a case report

Abstract Background Parathyroid hormone-related protein (PTHrP) is often the underlying cause of malignancies complicated by hypercalcemia. However, in rare instances, ectopic production of parathyroid hormone (PTH) by tumors can be responsible, with hypercalcemia rarely reported. Case presentation We report the case of a 55-year-old female who was admitted with general fatigue and developed acute consciousness disturbance with a rapid rise in intact serum PTH to 12,258 pg/mL and corrected calcium to 14.3 mg/dL. Despite zoledronic acid administration, hypercalcemia remained refractory and required hemodialysis. Calcium levels and consciousness improved; however, her overall condition deteriorated, and she eventually succumbed to progressive hepatic failure. Postmortem examination revealed multiple metastases from ectopic PTH-producing cervical cancer. Conclusions Although ectopic PTH-producing malignancies are extremely rare, ectopic PTH-producing tumors should be considered when unexplained hypercalcemia with negative PTHrP is encountered. Prompt initiation of hemodialysis is warranted in patients with severe symptomatic hypercalcemia.