[Retrosternal parathyroid gland cystic neoplasm as a cause of primary hyperparathyroidism].

Parathyroid carcinoma is a rare cause of primary hyperparathyroidism (1-2%). In this paper a case of parathyroid cancer of the right inferior parathyroid gland cyst (5 cm in diameter) localised mostly retrosternally is presented in a patient suffering from severe hypercalcaemia (Ca--3.7 mmol/l, Ca(++)--1.8 mmol/l), severe bone pains and weakness, huge osteoporosis with following L5 compression fracture and recurrent nephrolithiasis. PTH blood level before surgical treatment was 1243 pg/ml (Norm: 10-60 pg/ml). In the preoperative ultrasonography of the neck, a lesion was found, but it was considered to be a cyst in the inferior pole of the right thyroid lobe. In a fine-needle biopsy from the lesion-colloid mass without any cells was found. In a 99mTc-MIBI scintigraphy of the neck a suspicion of focus lesion in the right superior parathyroid gland was made, which was not confirmed intra-operatively. Parathyroid carcinoma was diagnosed intraoperatively in histological examination. 'En block' resection of the retrosternal parathyroid tumor and right thyroid lobe was performed from the jugular incision. Any enlarged jugular lymph nodes were not found. In a postoperative period a transient hypocalcaemia was present, which disappeared after pharmacological treatment. During 32 months of follow-up neither no features of local recurrence nor distant metastases were found. Calcium level in blood was normal, PTH 216.0 pg/ml, severity of bone pains and weakness lessened, osteoporosis in a course of pharmacological treatment--with no further progress.