Intrathyroid Parathyroid AdenomasUncommon Tumours at Unusual Sites: A Cross-sectional Study

Abstract

Introduction: Ectopic Intrathyroid Parathyroid Adenomas (ITPAs) are rare and known to pose preoperative and intraoperative diagnostic challenges in localisation, resulting in failure of parathyroid surgery. The common histopathological features of these tumours are not elaborately described in literature. Aim: To describe the clinico-pathological features of ITPAs, identified among all parathyroid adenomas, diagnosed at a tertiary care hospital. Materials and Methods: This was a cross-sectional study of all ITPAs diagnosed between January 2012 to December 2019, at Christian Medical College and Hospital, Vellore, Tamil Nadu. The gross examination and microscopic findings of ITPAs were reviewed and tabulated. Clinical, radiological and intraoperative findings were compiled to obtain preoperative and intraoperative diagnostic rates. Results: Among 409 parathyroid adenomas, there were ten ITPAs (2.4%), with eight ectopic inferior (80%) and two ectopic superior parathyroids (20%). Four ITPAs were completely intrathyroid (0.97%). Histopathological features of ITPAs were those of usual parathyroid adenomas. Four patients (40%) had concomitant thyroid disease, including one papillary microcarcinoma (10%). Correct preoperative diagnostic rate was 40%. Intraoperative misjudgment of location occurred in two patients (20%). Conclusion: ITPAs are rare and correct preoperative and intraoperative diagnosis may not be always possible. Histopathological evaluation of suspicious intrathyroid nodules is necessary in such instances to correctly diagnose them.

Keywords

• benign
• ectopic
• neoplasm
• parathormone
• thyroid nodules