Endocrine Abstracts

Background

Most cases of primary hyperparathyroidism (PHPT) is caused by a single benign adenoma, multiple parathyroid neoplasms (MPN) occur less often in 10–15%, parathyroid carcinoma accounts for <3%. MPN can be sporadic or develop due to inherited genetic syndromes (most commonly multiple endocrine neoplasia syndrome type 1 (MEN-1) that usually manifest at a young age. The preoperative examination of patients with MPN is important for achieving acceptable cure rates.

Aim

To describe the young patient with severe sporadic PHPT and giant parathyroid neoplasms.

Clinical case

34-year old woman presented with tooth damage, permanent neck ache, pains in lower extremities and general weakness. She had an episode of renal colic and previous fracture of metatarsal bone. There were no other diseases and no family history of endocrinopathies. Lab tests revealed severe PHPT: albumin-adjusted calcium level 3.0 mmol/l (reference range 2.15–2.55), PTH 403.7 pg/ml (16–65), 24-h urinary calcium 11.0 mmol (2.5–8). Other estimated parameters were osteocalcin 100.9 ng/ml (11–43), b- Tx 1.31 ng/ml (0.01–0.69), GFR 120 ml/min/1.73 m². We detected a significant decrease in bone mineral density (BMD) in all areas, maximal in Radius (-4.9 S.D., Z-score). CT scans confirmed the osteitis fibrosa cystica, Th12-vertebral fracture, as well as bilateral nephrolithiasis. Ultrasound and SPECT/CT showed multiple tumors in right (6.6×4×16 mm) and both left parathyroid glands (27×22×59 mm and 15×12×39.3 mm). The tumor of the left lower parathyroid gland covered the carotid artery. Clinical data allowed to suspect MEN-1 or the parathyroid cancer. Diffusion-weighted MRI was additionally completed (ADC 1.6–1.7×10^-3 mm²/s). Genetic testing excluded CDKN, CDC73, MEN1 mutations. The patient underwent the removal of three identified tumors. Morphological examination diagnosed benign adenoma of the both left and hyperplasia of the right parathyroid glands. Post-surgery hypocalcemia (serum calcium 1.67 mmol/l, PTH 57 pg/ml) and severe hungry bone syndrome were managed with alfacalcidol, calcium carbonate and cholecalciferol. The follow-up one year after surgery revealed increased PTH (80.25 pg/ml) with normocalcemia (2.4 mmol/l) and adequate 25(OH)D level, but 7-day stimulation test with alfacalcidol confirmed the PHPT persistence (serum calcium 2.57 mmol/l, PTH 113 pg/ml). The ultrasound showed the residual tissue between brachiocephalic and left carotid arteries (14 × 19 × 20 mm). Given the patient’s refusal to reoperate and significant improvement of target organs, we decided to continue the active observation and cholecalciferol treatment.

Conclusion

MPN remains a quite difficult condition with high rate of recurrent or persistence PHPT. It requires extensive preoperative diagnostics and explorative surgery. The long-term follow-up is mandatory in such patients.