CASE REPORT Parathyroid Carcinoma in a Dialysis Patient Satishkumar Jayawardene, MRCP, William J. Owen, FRCS, and David J.A. Goldsmith, FRCP ● A 75-year-old woman who had been receiving dialysis for 3 years and had a long history of chronic renal failure attributable to reflux nephropathy was investigated for progressive hypercalcemia in the context of very high intact parathormone (iPTH) levels. Imaging showed two functional parathyroid glands in the neck. At parathyroidectomy, four variously enlarged parathyroid glands were found and completely resected, without autotransplantation. The histology of one of the glands showed invasive parathyroid carcinoma. Parathyroid carcinoma is a very rare condition, with only 16 previous cases involving dialysis patients described in the literature. We review the literature to draw together presentational and therapeutic information on the management of this problem in the setting of renal replacement therapy. © 2000 by the National Kidney Foundation, Inc. INDEX WORDS: Parathyroid; hyperparathyroidism; carcinoma; renal failure; female. A LTHOUGH hyperparathyroidism is common in dialysis patients, parathyroid carcinoma is not. Very few cases have been reported. We report a second case from our unit and provide a comprehensive literature review. CASE REPORT A 60-year-old woman came to the renal department in 1980 with proteinuria, hypertension, and renal impairment (creatinine, 190 mol/L) caused by reflux nephropathy. There was a family history of diabetes (sister) and chronic renal failure caused by reflux nephropathy (two sisters), but no endocrine history. She was hypercalcemic in 1980 (uncuffed albumin-corrected plasma calcium was 2.76 mmol/L). Bone appearances from a radiologic skeletal survey were normal. Plasma parathyroid hormone (PTH) (nonspecific assay) was 0.54 g/L (normal, 0.1 to 0.73 g/L). Over the next 12 years, BP control was inconsistent and often poor despite vigorous therapy. She remained mildly hypercalcemic (range, 2.54 to 2.80 mmol/L). Because of this, she did not receive vitamin D therapy until, in 1992, she reached end-stage renal failure and started peritoneal dialy- sis, after which for phosphate control she also started oral calcium carbonate therapy. By 1994, plasma calcium had risen to 3.01 mol/L and intact PTH (iPTH) (specific assay) was 1,303 nmol/L (normal, 15 to 65 nmol/L). A thallium- technetium parathyroid subtraction scan showed two en- larged functional parathyroid glands on the neck, which findings were replicated by a parathyroid ultrasound scan. Nothing was palpable in the neck. At surgical parathyroidectomy (PTX), four enlarged glands were removed in their entirety. Histology of the four re- moved glands showed nodularity, but in one there was also monotonous cellularity and clear evidence of cellular inva- sion into the gland capsule and into one blood vessel (Figs 1 through 3). No mitoses were seen. In the immediate postoperative period, plasma calcium decreased from 3.18 mmol/L to 1.89 mmol/L. Plasma alka- line phosphatase rose from 218 to 543 IU/L. She needed calcium carbonate and large doses of oral 1-alfacalcidol postoperatively to maintain safe blood calcium levels. PTH was detectable postoperatively (within 6 weeks, 25 nmol/L) but remained within the normal range despite post-PTX hypocalcemia. Over the next 4 years to the current day, plasma calcium has slowly risen to 2.54 mol/L, with a mildly elevated PTH (161 nmol/L). The patient is now on hospital-based hemodialysis with no cervical or general symptoms. Recent isotope and ultrasound imaging of the neck and a positron-emission tomography scan have not shown any evidence of local tumor recurrence. DISCUSSION The diagnosis of primary malignant change of the parathyroid glands is very rare; the first case was reported in 1938, 1 and to date, only approxi- mately 300 cases are in the literature. It is thought that the incidence of parathyroid carcinoma in primary hyperparathyroidism is in the range of 0.5% to 5%. 2,3 There is a well-known but very rare associa- tion between familial hyperparathyroidism, as part of multiple endocrine neoplasia (MEN) and parathyroid carcinoma. 4 The cause of the more common, sporadic, cases is unclear. The female: male ratio in these sporadic cases was 2:1. 5 Parathyroid hyperplasia as a precursor to carci- noma has been reported and suggested previ- From the Renal Unit, Surgery Department, Guy’s Hospi- tal, London, United Kingdom. Received February 15, 2000; accepted in revised form May 26, 2000. Address reprint requests to David J.A. Goldsmith, FRCP, Consultant Nephrologist, Renal Unit, Guy’s Hospital, London SE1 9RT, United Kingdom. E-mail: David. goldsmith@gstt.sthames.nhs.uk © 2000 by the National Kidney Foundation, Inc. 1523-6838/00/360-0030$3.00/0 doi:10.1053/ajkd.2000.17733 American Journal of Kidney Diseases, Vol 36, No 4 (October), 2000: E26 1