Esophageal Cancer Initially Presenting as Severe Paraneoplastic Hypercalcemia Requiring Hemodialysis

Paraneoplastic hypercalcemia without bone metastasis occurs rarely in esophageal cancer. A 75-year-old man was admitted for general weakness and lethargy. Laboratory data showed high serum calcium level (corrected calcium 14.6 mg/dL), low parathyroid hormone level (3.3 pg/mL) and high parathyroid hormone-related peptide level (3.5 pmol/L). Esophagogastroscopy showed a malignant tumor in the esophagus. Histology showed moderately differentiated squamous cell carcinoma. Bone scan showed no evidence of bone metastasis. Since the patient's calcium levels remained high and mental state did not show improvement despite intravenous fluid therapy, diuretics and intravenous bisphosphonate, hemodialysis was started. After hemodialysis treatment, the serum calcium level subsequently normalized and his mental status improved. Herein, we report a rare case of paraneoplastic hypercalcemia in a patient with esophageal cancer.