Ectopic parathyroid adenoma: single-centre experience from India
CV Harinarayan1, Honey Ashok2, Adil Sadiq3, GR Prashant4, Divya Badanidiyur2, Neha Gupta2, Indira Rajani3, NK Sunil Kumar3, Shabnam Roohi5, G Nandita5
1 Institute of Endocrinology, Diabetes, Thyroid and Osteoporosis Disorders, Bengaluru, Karnataka, India
2 Department of ENT, Sakra World Hospitals, Bengaluru, Karnataka, India
3 Department of Cardiothoracic and Vascular Surgery, Sakra World Hospitals, Bengaluru, Karnataka, India
4 Department of Nuclear Medicine, Health Care Global Hospitals, Bengaluru, Karnataka, India
5 Department of Laboratory Medicine and Pathology, Sakra World Hospitals, Bengaluru, Karnataka, India
C V Harinarayan
Director, Institute of Endocrinology, Diabetes, Thyroid and Osteoporosis Disorders, Bengaluru, Karnataka
Source of Support: None, Conflict of Interest: None
Background: The commonest cause of primary hyperparathyroidism (PHPT) is hyperfunctional parathyroid adenoma (PA) (94%), parathyroid hyperplasia (<6%) and rarely parathyroid carcinoma (<1%). Excision of PA is a definitive cure with a success rate of 95%. Less than 15% have one or more hyperfunctioning glands in an ectopic location.
Methods: Between 2014 to 2017, seven of the 13 patients with PHPT, who had failed surgical and noninvasive localisation, were included in the study. Hybrid localisation technique positron emission tomography-Computed tomography (PET-CT) with tracer 11C-choline was used. Location of parathyroid adenoma was classified using Perrier classification, which uses, letters A-G to describe the exact location of the adenoma. A 50% drop in PTH levels as compared with pre-incision values was confirmed as a cure.
Results: The biochemical and hormonal profile of the 7 (54%) patients with ectopic PA are (mean±SD) serum calcium (mg/dL), 25OH-D (ng/dL) and PTH (pg/mL) 11.36 ± 0.82; 22.82 ± 8.57; 205 ± 105 respectively. Three of the seven had renal stones. In all, seven patients of PA were localised using PET-CT using tracer 11C-choline. The profile of PA were two type-G (intrathyroidal), one type-C (posterior mediastinum), two type-F (superior mediastinum), one of type D (mid region of posterior surface of thyroid parenchyma at the junction of recurrent laryngeal nerve and the middle thyroid vein) and one type B.
Conclusion: Ectopic PA is rare. In a biochemically and hormonally confirmed PHPT and in failed imaging localisation techniques/failed neck exploration one should look for ectopic PA. Newer hybrid techniques combined with newer tracer agents (PET-CT) will help in localization of PA. To the best of our knowledge this is the first report of series of ectopic PA from a single center from India.