Endocrine Abstracts

Introduction: Parathyroid carcinoma (PC) is an extremely rare, aggressive and life-threatening form of primary hyperparathyroidism (pHPT). PC accounts for less than 1% of cases of pHPT, predominantly diagnosed in the fifth or sixth decades of life. Most parathyroid carcinomas are diagnosed after surgery.

Case description: A 51-year old man was admitted to the Hospital of Lithuanian University of Health Sciences, Kaunas clinics due to leg pain and general weakness. It is known from the medical history that kidney stones were observed in 2008. Ten years later hypercalcemia and chronic kidney disease (GFR – 12.6 ml/min per 1.73 m² (90–120)) was confirmed.

Laboratory tests: Hypercalcemia (Ca – 2.91 mmol/l (normal range 2.15–2.50), normophosphataemia (P – 1.25 mmol/l (0.81–1.45), ↑ uremic measurements (creatinine – 423 µmol/l (62-106), urea – 18.30 mmol/l (1.8–8.3), anaemia (Hb – 114 g/l (130–160), significantly ↑ PTH – 260.6 pmol/l (1.26–6.74), thyroid function was normal. Ultrasound investigation of the thyroid revealed normal echogenicity, homogeneous thyroid parenchyma and heterogeneous hypoechoic focal area with micro and macrocalcifications under the right lobe. US of abdominal cavity revealed the signs of nephrocalcinosis. Spine and pelvic X-ray revealed an old compression fracture of the Th-9 vertebral body and old fracture of the right iliac wing. DXA– osteoporosis: T-score −3.0 in the spine. The diagnosis of the parathyroid adenoma was denied after performing the parathyroid scintigraphy. Conservative treatment of hypercalcemia was performed with infusion therapy. The right inferior parathyroidectomy and right thyroid lobectomy was performed. The size of the parathyroid tumour was 4.5×4×3.5 cm, the weight of the specimen- 31 g. Histologically: carcinoma of the parathyroid gland pT1 LVi1. Tumour cell mitosis was monitored (5 mitosis/10 DPRL). Ki67 proliferation index was positive up to 5% of the cells. The MEN syndrome was denied, no mutation found. No metastasis of the tumour was observed. Persistent hypocalcaemia and hungry bone syndrome lasted for about a month after the surgery. Normocalcemia was achieved after the long-term treatment with alfacalcidol and calcium carbonate. The patient came to the endocrinologists for medical check-up after one year. Renal replacement therapy with an increasing need for dialysis was started. No recurrence of parathyroid tumour was observed. Ca–P homeostasis were in normal ranges.

Conclusion: Due to lack of local symptoms and slow progression this disease is often underdiagnosed. In most of the cases the PC diagnosis is confirmed by accidental removal of the parathyroid gland or after the manifestation of multiple chronic hypercalcaemia complications.