Sudden onset of parathyroid hormone-independent severe hypercalcemia from reversal of tumoral calcinosis in a dialysis patient.
BACKGROUND
Tumoral calcinosis is a rare manifestation of extraskeletal calcification, featuring large calcified cystic masses in the periarticular regions of large joints. In chronic kidney disease (CKD), this disorder is thought to evolve through a chronically elevated calcium-phosphorus solubility product leading to calcium precipitation in soft tissue. Treating tumoral calcinosis in these patients involves interventions to lower the calcium-phosphorus product such as reduction in vitamin D therapy and intensive hemodialysis regimens.


METHODS
We report the case of a 54-year old woman with polycystic kidney disease on peritoneal dialysis with widespread tumoral calcinosis in the context of hypercalcemic tertiary hyperparathyroidism who had been on long-term alfacalcidol therapy. After withdrawal of the vitamin D analogue and initiation of daily hemodialysis, there was rapid dissolution of her tumoral calcium deposits with the abrupt onset of parathyroid hormone (PTH)-independent transient hypercalcemia that resolved once the soft tissue deposits disappeared.


CONCLUSIONS
Resorption of soft tissue calcific deposits may result in transient parathyroid hormone (PTH)-independent hypercalcemia. In CKD patients, this hypercalcemia causes a decrease in the PTH level, distinguishing it from tertiary hyperparathyroidism, though PTH may not be totally suppressed, the way it is seen in PTH-independent hypercalcemia in non-CKD patients.
Department of Medicine, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada. fbkamar@ucalgary.ca.
Fareed B
FB
Kamar
Department of Medicine, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada.|Department of Critical Care Medicine, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada.
Bikaramjit
B
Mann
Department of Medicine, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada.
Gregory
G
Kline
Chronic kidney disease; Hemodialysis; Hypercalcemia; Hyperparathyroidism; Metastatic calcification; Parathyroid hormone; Peritoneal dialysis; Tumoral calcinosis
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