Presentation of a PTHrP-secreting pancreatic neuroendocrine tumour, with hypercalcaemic crisis, pre-eclampsia, and renal failure

Abstract

Severe hypercalcaemia during pregnancy is rare and most cases are secondary to hyperparathyroidism. This is the first report of a parathyroid hormone related protein (PTHrP) secreting neuroendocrine tumour of the pancreas manifesting with severe hypercalcaemia during pregnancy. Measurement of PTHrP was useful in both the diagnosis and follow up of our patient and should be considered in the diagnostic workup of patients with unexplained hypercalcaemia. A raised PTHrP concentration is a strong indicator of malignancy. S evere hypercalcaemia is rare during pregnancy. Most cases are due to hyperparathyroidism but there are fewer than 150 patients reported in world literature.1 There have been two reports of the milk alkali syndrome 2 and four reported cases of parathyroid carcinoma during pregnancy. 3Other cases of malignancy related hypercalcaemia in pregnancy are very rare.Parathyroid hormone related protein (PTHrP) was first isolated in 1987 from cancer cell lines and a tumour associated with hypercalcaemia, and is now considered to be the main mediator of humoral hypercalcaemia of malignancy.4 5 The placenta (during pregnancy) and mammary glands (postpartum) are important physiological sources of PTHrP. 6 We report a case of extreme hypercalcaemia manifesting during pregnancy. The hypercalcaemia was associated with raised levels of 1,25-dihydroxyvitamin D 3 (1,25(OH) 2 D 3 ) and was eventually found to be due to a PTHrP secreting pancreatic neuroendocrine tumour. CASE REPORTA 25 year old woman presented at 29 weeks' gestation with altered consciousness, headache, hypertension and proteinuria, and was initially thought to have pre-eclampsia. She was noted to have taken 1 g of mefenamic acid in divided doses during the two days before presentation.Her initial investigations showed a serum calcium adjusted for albumin of 5.9 mmol/l (reference range 2.2-2.6). A retrospective measurement of calcium at 19 weeks' gestation was obtained at 2.33 mmol/l. Her serum phosphate was raised at 2.07 mmol/l (reference range 0.7-1.2), probably as a result of her renal impairment. She had renal failure with a serum creatinine of 328 µmol/l (reference range 60-110) and her 24 hour urinary protein was 9.09 g. Parathyroid hormone was undetectable using a two site immunoradiometric assay (Diagnostic Product Corporation Immulite, Los Angeles USA).Her early management consisted of an emergency caesarean section followed by transfer to the intensive therapy unit. She was given five intravenous doses of pamidronate 15 mg twice daily. In the postpartum period calcium decreased rapidly after pamidronate and she required calcium supplements for one month. The calcium decreased to a nadir of 1.9 mmol/l then subsequently steadily increased to 2.68 mmol/l at 12 months and 2.76 mmol/l at 15 months. Her renal function improved rapidly with serum creatinine decreasing to 99 µmol/l at 10 days but the proteinuria took six months to normalise.Serum parathyroid hormone concentrations were undetectable on three occasions between three and 12 months ...

Bone Development and Mineral Homeostasis in the Fetus and Neonate: Roles of the Calciotropic and Phosphotropic Hormones

“…XII, A, B, and G). These findings have been observed in babies born of mothers whose hypercalcemia during pregnancy was caused by primary hyperparathyroidism (79,149,304,393,609,718), inactivating mutations of Casr (529), or hypercalcemia of malignancy (9,131,278,454,529,673,674,700). Conversely, maternal hypocalcemia caused by hypoparathyroidism (11,76,389,586,652,710) or pseudohypoparathyroidism (226,710) has been associated with fetal parathyroid gland hyperplasia, normal cord blood calcium, increased PTH, and effects on the fetal skeleton that include increased resorption, demineralization, and fractures occurring in utero or during delivery (see sect.…”

“…Hypercalcemia may be present in cord blood and the first few postnatal samples (131,278,700), but the calcium will fall and may reach severely hypocalcemic values with attendant risk of respiratory distress, tetany, and seizures (9,454). One of four babies died where the outcome was reported (454).…”

Parathyroid Hormone Related Peptide (PTHrP): A Mini-Review

“…Because of the death of these mice at birth the role of PTHrP in the physiology of islets is not known. Neuroendocrine tumors secreting PTHrP resulting in hypercalcemia has been described [76,78].…”

Delayed graft function in renal transplantation

“…Acute renal failure in native kidneys has been reported in patients with serum calcium levels above 3.5 mmol/L. In native kidneys, acute renal failure due to hypercalcemia is describer in the milk alkali syndrome (89), severe hyperparathyroidism or PTH-related proteins (PTHrP) associated conditions (90) or multiple myeloma (91) and vitamin D intoxication (92). Little is known about the effects of hypercalcemia on the initial function of renal allografts.…”

“…The role of the induction of this gene expression after acute renal injury lies probably in their involvement in determining cell fate (survival versus apoptosis or necrosis) and the transcription of growth factors and their receptors that ultimately mediate tubular cell division and proliferation. Upon ischemia and reperfusion injury growth factors like the hepatic growth factor, insulin like growth factors and fi broblast growth factors are upregulated (89,90). Others like epidermal growth factors are down regulated in injured proximal tubules (91).…”