Parathyroidectomy in a hypercalcaemic patient with inappropriately normal plasma parathyroid hormone: an unusual way to arrive at the correct diagnosis.

Keywords: angiotensin-converting enzyme; hyper-hyperplasia, although the signal was particularly intense in the region of the left lower gland. calcaemia; hyperparathyroidism; parathyroidectomy; The patient was referred for surgical parathyroidec-parathyroid hormone; sarcoidosis tomy. Four glands were identified, all of which appeared enlarged. Three whole glands plus a section of the fourth gland were removed. Generalized chief cell hyperplasia of all four glands was found on histo-Case logical analysis. There was little change in plasma calcium during A 49-year-old Caucasian man presented with a the peri-operative period and a decision was made to 2-month history of lethargy, nausea, anorexia, weight remove the remaining parathyroid tissue. Histological loss and polyuria. He was cachectic and mildly dehyd-examination again showed hyperplastic change within rated. Laboratory analysis showed: plasma calcium, the gland. More significantly, a granulomatous lesion 3.45 mmol/l (corrected to a reference plasma albumin containing giant cells was noted in sections of an of 40 g/l using a factor of 0.02 mmol/g albumin); excised lymph node (Figure 1a and b). This was ini-alkaline phosphatase, 160 IU/l (normal range 32–90 tially considered to be a reaction to a metal clip left in IU/l); urea, 17.5 mmol/l; and creatinine, 496 mmol/l. situ after the first operation. Haemoglobin was 10.5 g/dl (normochromic, normo-Plasma calcium levels remained high, despite regular cytic pattern). The following investigations gave oral clodronate, and the patient was referred to our normal results: protein electrophoresis of urine and centre. Additional tests suggested a predominantly serum, X-rays of chest, hands and skull, and bone hepatic source of plasma alkaline phosphatase, and scintigraphy. Serum angiotensin converting enzyme gamma-glutamyl transferase was raised. This informa-(ACE), prostate-specific antigen, alanine amino-tion, together with the histopathology report of the transferase and thyroid stimulating hormone were lymph node, raised the possibility of sarcoidosis. all within normal ranges. Parathyroid hormone (PTH), Granulomata were found in a liver biopsy specimen intact molecule assay, was 4 mg/dl (normal range (Figure 2). Chest X-ray and physical examination 3.5–16 mg/dl, depending on plasma calcium). remained unremarkable. He was treated initially with intravenous fluids, then The patient was treated with high dose oral steroids. frusemide and pamidronate. Plasma calcium fell to Within weeks, plasma calcium and alkaline phosphat-2.66 mmol/l and plasma creatinine to 300 mmol/l. No ase levels had returned to the normal range. Serum further therapy was pursued. creatinine fell from 300 to 160 mmol/l on correction of At review several weeks later, plasma calcium the hypercalcaemia. was 3.03 …