Parathyroid carcinoma case-report in a patient with multinodular goiter and chronic kidney disease: difficulties in diagnosis and treatment (observation from practice)

We would like to present a clinical case of severe primary hyperparathyroidism due to a parathyroid carcinoma of atypical location in a patient with chronic kidney disease of complex etiology and multinodular goiter. Patient S., 59 years old, was followed-up for a long time in tertiary referral hospitals for “chronic tubulointerstitial nephritis with nephrosclerosis”, secondary hyperparathyroidism due to chronic kidney disease (CKD) G3–4, osteoporosis, and a multinodular euthyroid colloid goiter. In July 2021 she was referred to the Endocrinology Research Centre in order to clarify the diagnosis because of the persistence of an extremely high level of parathyroid hormone (PTH) despite cinacalcet treatment. During examination, primary hyperparathyroidism, a left parathyroid gland lesion, multinodular goiter with subclinical thyrotoxicosis, and vitamin D deficiency were diagnosed. After the removal of the left parathyroid gland lesion (histologically confirmed parathyroid carcinoma) and a left-sided hemithyroidectomy, hypocalcemia («hungry bone syndrome») developed, but the level of parathyroid hormone remained elevated. After 3–18 months after surgery, no data for relapse of primary hyperparathyroidism was obtained. The persistent moderate increase in PTH was regarded as secondary hyperparathyroidism in CKD and hypocalcemia. Complex therapy of osteoporosis with the antiresorptive drug denosumab, vitamin D and its active metabolite, calcium preparations, and parathyroidectomy led to a significant increase in bone mineral density (BMD) and no repeated fractures 18 months after surgery.Conclusion. In patients with pre-dialysis CKD and high PTH levels, it is necessary to make a differential diagnosis between primary (PHPT) and secondary hyperparathyroidism (SHPT). Severe manifestations of primary hyperparathyroidism can be suspicious for parathyroid carcinoma.