Primary hyperparathyroidism in patients with gastric carcinoid tumors type 1: an unusual coexistence

Abstract

Objective: Although a number of familiar syndromes are associated with primary hyperparathyroidism (PHP), there is no information regarding the prevalence of PHP in other sporadic neuroendocrine diseases. The aim of this study is to investigate the prevalence of PHP in our group of patients with gastric carcinoid (GC) type 1 tumors.

Methods: Twenty-six patients with biopsy-proven GC type 1 tumors were retrospectively studied. The diagnosis of PHP was suspected following elevated or high-normal serum calcium levels and elevated or inappropriate normal parathyroid hormone levels. Further tests for the localization of the hyperfunctioning parathyroid glands included neck ultrasound, (99m)Tc-SESTAMIBI scanning, and cervical or upper mediastinal MR imaging studies. Four control groups were also studied: two age- and sex-matched groups of individuals with (n = 49) and without (n = 34) thyroid autoimmunity and normal endoscopy of the stomach, a third group with nongastric neuroendocrine tumors (n = 68), and a fourth group with atrophic gastritis and hypergastrinemia, without gastric endocrine tumors (n = 30).

Results: PHP was diagnosed in 4 (15.38%) patients with GC type 1 tumors compared to none of the 4 control groups. Three of the 4 patients with PHP were operated and proved to have a parathyroid adenoma. No statistically significant differences were observed between patients with or without PHP in mean gastrin and chromogranin A levels, number of lesions, ki-67 labeling index expression, and maximum GC type 1 tumor diameter.

Conclusion: PHP seems to be relatively common, approximately 15% in the present cohort, in patients with GC type 1 tumors. PHP should be actively looked for in such patients and treated accordingly.