Endocrine Abstracts

Parathyroid carcinoma (PTCa) is an uncommon cause of primary hyperparathyroidism (PHP), statistically representing <1–2% of all cases of PHP. Early resection of the primary tumor is the only curative treatment, however this is frequently incomplete. As a consequence, recurrence of PTCa presenting as locally invasive tumor and/or metastatic process is not rare. Morbidity and mortality are generally caused by the effects of unremitting hypercalcemia rather than tumor growth.

We present our own experience with management of the patient with PTCa. After the diagnosis of PHP was established, during two months patient underwent two unsuccessful surgeries (without histological confirmation of parathyroid tissue. Severe hypercalcemia 4.47 mmol/l with PTH-I level 600 pg/ml (reference value < 68.3) was reason for urgent admission one month later. MRI showed pathological jugular mass with enlargement of supraclavicular, submandibular and paracarotid lymph nodes. Tumoral mass was only partially removed. PTCa with infiltration of the thymic tissue was confirmed histologically. PET showed residual hypermetabolic mass (with latero-lateral distance 3.1 cm) and multiple bilateral lung metastases (14 in right lungs, 12 in left lungs). Due to the metabolic instability and size of the tumor residuum, patient was not appropriate candidate for immunization with parathormone fragments – novel and perspective modality in medical therapy of PTCa. Worsening clinical course of the patient and progression of lung metastases unabled repeated sugery. Rapid increase of calcemia to 5.60 mmol/l required acute hemodialysis and consequent hemodialyses in every other day intervals. Despite multinodal medical therapy – increased fluid intake, loop diuretics, parenteral bisphonates (pamidronate and zolendronate) and calcimimetics (cinacalcet) and finally hemodialysis, patient died after 12-month duration of the disease.

We are awaiting the results of molecular analysis of HRPT2 gene. The identification of a mutation would be valuable as question remains whether genetic testing of HRPT2 gene should be offered to and performed in all patients with PTCa and in all at-risk relatives of a patient who has PTCa with an HRPT2 germ-line mutation. Monitoring serum calcium levels in all persons at risk provides an alternative to definitive DNA diagnosis.