Rare cause of 1,25-dihydroxy vitamin D mediated hypercalcemia: A case report and literature study

Bellefroid J de; den Bruel A Van; S Vandecasteele

doi:10.1530/endoabs.57.025

Background: 1,25-dihydroxy vitamin D mediated hypercalcemia resulting from an inflammatory reaction caused by a foreign body such as a textiloma has never been described.

Clinical case: A 61 year-old man with a medical history of Alport syndrome and in need of chronic dialysis after transplant kidney resection because of relapsing severe urinary tract infections, presented with recurrent and progressive hypercalcemia two years after parathyroidectomy (C and B) because of tertiary hyperparathyroidism. There was no intake of calcium supplements or diuretics. Laboratory evaluations showed a normal 25-hydroxyvitamin D but an elevated 1,25-dihydroxyvitamin D and an inadequately normal PTH (Table 1). A ⁹⁹mTc parathyroid scintigraphy could not show any adenoma. In order to localize a possible inflammatory process, an FDG-PET-CT was performed and revealed an abdominal mass with a high metabolic captive border. Four days later the patient arrived at dialysis and showed signs of fatigue. Inflammatory values were high. He was admitted to the hospital and empirical antibiotics were started. Despite the antibiotics, inflammatory parameters raised and the patient complained of progressive abdominal pain. A diagnostic laparotomy was performed and revealed a textiloma (a surgical gauze). After removal of the textiloma a complete normalization of the hypercalcemia and 1,25-dihydroxyvitamin D was observed.

**Table 1** Laboratory results.
Lab	Value	Value after surgery	Reference value
Calcium	2.88 mmol/l	2.50 mmol/l	2.2–2.55 mmol/l
Phosphorous	1.80 mmol/l	1.08 mmol/l	0.81–1.45 mmol/l
PTH	23 ng/l	218 ng/l	15–65 ng/l
25-hydroxyvitamin D	47 ng/ml	53.3 ng/ml	>30 ng/ml
1,25-dihydroxyvitamin D	172,6 pmol/l	45.9 pmol/l	<5–42 pmol/l
Serum creatinine	13.6 mg/dl	8.8 mg/dl	0.6–1.2 mg/dl

Conclusion: Hypercalcemia mediated by 1,25-dihydroxy vitamin D is rather uncommon. Well-recognized etiologies are sarcoidosis and lymphomas. Less than 10 case reports were found where the underlying cause was a foreign body exposure, no case was found where the foreign body was a textiloma. The underlying mechanism remains unclear, but the literature mainly suggests that a foreign body reaction results in formation of foreign body granulomas. Activated macrophages express 1-α hydroxylase which transforms 25-hydroxyvitamin D into 1,25-dihydroxyvitamin D, leading to hypercalcemia.

References: 1. A. a. S.-Y. Ren, “Autoregulation of 1,25-dihydroxyvitamin D synthesis in macrophage mitochondria by nitric oxide’, The Endocrine Society, pp. 4514–4517, 1996.

2. M. Kallas, “Rare causes of calcitriol-mediated hypercalcemia: a case report and literature review”, J Cllin Endocrinol Metab, pp. 3111–3117, 2010.

3. P. J. Donovan, “Calcitriol-mediated hypercalcemia: causes and course in 101 patients”, J Clin Endocrinol Metab, pp. 4023–4029, 2013.

Endocrine Abstracts

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