Category: Calcium/Bone Disorders
Objective : Discuss the clinical presentation of parathyroid carcinoma.
Methods : Case report.
Results : A 76 year old man presented with acute mental status (MS) changes, a serum Ca of 16.3 mg/dL (normal 8.5-10.5), creatinine 3.5 mg/dL, up from a baseline of 1.8 (normal 0.6-1.2), albumin 3.5 g/dL (normal 3.4-4.8) and PTH > 5000 pg/mL (normal 10-65). He had PHPT diagnosed in 2015 (Ca was 12.4 and PTH 432) but had declined therapy. He had no neck masses. He received intravenous (IV) normal saline, calcitonin 200 units subcutaneously (SC) every 8 hours for 3 doses, cinacalcet 30 mg orally twice daily and one dose of 90 mg of IV Pamidronate. As his Ca further increased to 18.1 mg/dl, he underwent hemodialysis twice using a low Ca bath and his Ca stabilized at 10.5-11 mg/dl for 3 days with concomitant MS improvement. His Ca increased again to 14mg/dl, so IV furosemide 60 mg twice daily was added, and cinacalcet and calcitonin were increased to 60 mg three times daily and 250 units every 6 hours respectively. Technetium-99m Sestamibi scan revealed a large retrotracheal mass highly suspicious for PCA. Because of his other co-morbidities, the patient decided against parathyroidectomy and opted for comfort care.
Parathyroid carcinoma is a rare cause of primary hyperparathyroidism. Benign parathyroid disease often presents with mild asymptomatic elevations of calcium and PTH, but parathyroid carcinoma presents with severe symptomatic hypercalcemia and a 5-10 fold increase in PTH. Parathyroid carcinoma should be suspected with severe symptomatic elevations of calcium and PTH, but can only be distinguished from the benign parathyroid disease on pathology after parathyroidectomy, and imaging usually does not differentiate the two conditions.
This case is unusual in that the patient was asymptomatic for several years despite severe hypercalcemia, and that imaging did actually suggest parathyroid carcinoma.
University of Iowa Hospitals and Clinics
Iowa City, Iowa
Dr. Adeyinka Taiwo is an Endocrine Fellow at the University of Iowa.