Endocrine Abstracts

Presence of primary hyperparathyroidism (PHPT) in patients with thyroid disease has been previously reported. However, co-existence of PTHPT and papillary thyroid cancer (PTC) has been reported very rarely, mainly in the form of isolated case reports. Since the pathophysiological mechanisms of the two diseases are theoretically quite different, no causal relation between these diseases has been inferred. The aim of this study was to investigate the presence of PHTP in individuals who underwent thyroidectomy for suspected thyroid cancer or large nodular goiter.

Patients and Methods: A retrospective observational study involving 3230 patients (24% men, mean age 49.8 years, and 76% women, mean age 47.7 years) who underwent total thyroidectomy in the Department of Endocrine Surgery, Euroclinic Hospital, Athens, Greece, over a period of 13 years (2005-2018). The patient groups were categorized according to histopathological criteria of the parathyroid and thyroid glands.

Results: 1945 patients (64%) had large benign nodular goiter, while 978 (32%) had papillary thyroid carcinoma. Among patients with benign nodules and those with papillary carcinoma respectively 16 (11 women/5 men) and 38 (33 women/5 men) had PHPT. The relative risk for coexistence of PHPT and PTC was 2.0 (95% CI 1.7 to 2.4, P<0.0001). The age groups between 30 and 60 years were associated with the highest relative incidence (82%) of PHTP, while there was sexual dimorphism, with a ratio of 4.4:1 in women vs. men.

Conclusions: Our study found that coexistence of PHPT and PTC is relatively common. As primary hyperparathyroidism is a chronic disease that is associated with many complications and requires early diagnosis and treatment, this co-morbidity should be considered in all patients requiring thyroidectomy for cancer. Further investigation of the possibly shared pathogenetic mechanisms between primary hyperparathyroidism and papillary thyroid carcinoma and is warranted.