LAUSR

Abstract Background Derangements of calcium metabolism are common in patients with cancer. 1 Unlike hypercalcemia which is well-recognized, little is known about hypocalcemia of malignancy. 2 In fact, there were only 2 studies published to date that investigated its incidence among cancer patients. 2,3 Clinical Case: A 40-year-old male consulted an ENT specialist for a 2×2 cm left parotid mass of 3 years duration. There was no fever, cough, night sweats or significant weight loss. Histological analysis of the mass revealed parotid gland adenocarcinoma. Tumor metastases to lung and spine were seen on PET CT scan. Consequently, he received 18 cycles of chemotherapy and 10 sessions of radiotherapy without surgery because of the advanced stage. He initially exhibited good response with the treatment. A year after,he developed shortness of breath, numbness of hands with seizure episode. Chest x-ray showed pleural effusion and osteoblastic changes while cranial CT scan revealed brain metastasis. Bone scintigraphywas evident for multiple osseous metastases. He underwent stereotactic brain surgery, and thoracentesis with pleural fluid analysis consistent with malignancy. Biochemical tests were remarkable for hypocalcemia (0.99, n>1.12 mmol/L, normomagnesemia (0.89, n>0.74 mmol/L), low vitamin D (11.6, n>30 ng/mL), elevated phosphate (1.73; n: <1.49 mg/dL), and elevated intact PTH which eventually dropped (157.7 to 9, n>15 pg/mL). Ultrasound of the neck revealed diffuse thyroid calcifications. Despite oral calcium supplementation (14.4 grams elemental calcium),calcium infusion (1.35 mg/kg/hour elemental calcium) and vitamin D supplementation (6000 IU cholecalciferol and 0.5 mg calcitriol daily), he remained hypocalcemic. His condition eventually worsened, and he succumbed to death in due course despite aggressive measures provided. Conclusion To our knowledge, this is the first case illustrating the therapeutic challenge in addressing an intractable hypocalcemia in the setting of an advanced parotid carcinoma inour country. Reference: (1)Carl Blomqvist. A Hospital Survey of Hypocalcemia in Patients with Malignant Disease. Acta Med Scand. 1986;220. (2) Schattner et al. Hypocalcaemia of Malignancy. The Netherlands Journal of Medicine. July 2016, Vol. 74, No. 6. (3) Goncalves. Hypocalcemia in cancer patients: An exploratory Study. Porto Biomed. J. (2019) 4: 4 Presentation: No date and time listed