A Case of Advanced Ovarian Cancer Associated with Hypocalcaemia

Presentation Number: SAT 330
Date of Presentation: April 1st, 2017

Kidmealem Zekarias*1, Amir Moheet2 and Almoutaz Shakally3
1Univeristy of Minnesota, Minneapolis, MN, 2University of Minnesota Medical Center, minneapolis, MN, 3University of Minnesota, Minneapolis, MN

Abstract

Introduction/Background: Hypocalcemia is a rare complication of malignant diseases.

A 58-yr-old woman with stage IVB Clear cell carcinoma of the ovary with extensive sclerotic bony metastasis is described here. She had a generalized multiple osteoblastic bone metastases.

Clinical case: Patient presented with bilateral upper and lower extremity weakness. She had prolonged QT interval on EKG; QTc was 508ms. Laboratory examination on admission showed that the ionized whole blood calcium level was 2.2 mg/dl (4.4-5.2 mg/dl), serum phosphorus was 3.6mg/dl (2.5 -4.5 mg/dl) Magnesium was 1.1 mg /dl (1.7-2.2 mg/dl), serum alkaline phosphatase was 402 U/L (40-150 U/L), 25 OH Vit D total was <12 ug/L (20-75 ug/L), normal 24 hour urine calcium, Parathyroid Hormone Intact was 134pg/ml (12-72 pg/ml) and GFR was within the normal limits. CT scan showed sclerotic lesions in the spine and pelvic with the appearance of metastatic disease and possible right sacral fracture. Bone scan showed multiple radiotracer uptake in the calvarium, proximal left humerus, right rib, cervical, thoracolumbar spine, sacrum, bilateral iliac bones, left proximal femur and bilateral proximal tibia.

After the initial correction of hypocalcemia and hypomagnesaemia with IV calcium gluconate and IV magnesium sulfate respectively; patient was treated with oral high dose calcitriol 0.5 mcg TID and liquid calcium 2500 mg TID. Acute symptoms of weakness and EKG changes resolved after IV replacement. Patient underwent total abdominal hysterectomy, bilateral salpingo-oophorectimy, lymph node dissection and was started on carboplatin and Paclitaxel. Hypocalcemia improved once treatment for the underlying issue is started however, patient needed ongoing intermittent magnesium infusion and oral supplementation due to chemotherapy induced magnesium wasting. Patient was continued on oral calcitriol, vitamin D supplement, oral calcium and magnesium supplementation.

Conclusion: Bone metastasis related hypocalcemia secondary to osteoblast activity is not a well-described cause of hypocalcemia. The likely main mechanism of hypocalcemia in a patient with extensive osteoblastic bone metastasis is increased deposition of calcium in the bones as a result of accelerated osteogenesis secondary to the extensive blastic metastases. Increased osteoblast activity leads to new bone formation without removal of the old one; a condition known as sclerosis. Early recognition, correction of vitamin D deficiency and treatment of hypocalcemia is essential in patients with metastatic cancer with osteoblastic bone metastasis.

 

Nothing to Disclose: KZ, AM, AS