Ectopic Parathyroid Adenoma in Piriform Sinus: Case Report and Review of the Literature

Case Report: Nine-year-old with parathyroid adenoma within the piriform sinus

We present the case of a 9-year-old girl who presented with symptomatic hypercalcemia from primary hyperparathyroidism (PHPT). Laboratory results revealed elevated serum calcium 12.1 mg/dl (ref: 9.1-10.4), elevated ionized calcium 6.8 (ref: 4.5-5.6) mg/dl, phosphorus 3.8 (ref: 3.3-5.1) mg/dl, 25-OH vitamin D 20.1 (30-100) ng/ml, and elevated intact PTH 70 (15-65) pg/ml, consistent with the diagnosis of PHPT. She had persistent hyperparathyroidism after bilateral neck exploration, left thyroid lobectomy, and transcervical thymectomy. Neither inferior gland was identified. No parathyroid tissue was seen on histology. Repeat preoperative imaging identified a 7-mm × 5-mm adenoma on 4DCT not seen on ⁹⁹Tc-sestamibi parathyroid scan. The patient then underwent a successful redo parathyroidectomy with removal of a submucosal left parathyroid adenoma at the superior aspect of the thyroid cartilage in the piriform sinus. Her biochemical work-up remains consistent with surgical cure 6 months after surgery. Herein, we also review common locations for ectopic parathyroid adenomas.

Clinical Trial Registration

NCT04969926.

Resection of an elusive parathyroid adenoma in the aortopulmonary window

Primary hyperparathyroidism (PHPT) is the most common cause of hypercalcaemia and is caused by a single parathyroid adenoma in the neck in 85% or more of patients. National Institute for Health and Care Excellence (NICE) guidelines published in May 2019 advise that preoperative imaging is offered prior to parathyroid surgery for PHPT if it will inform surgical approach. If imaging, typically a neck ultrasound and a second modality that may use ionising radiation, does not identify the adenoma or is discordant, it is advised that surgery is performed by a surgeon with expertise in the management of unlocalised parathyroid disease.The cure rate in such cases is over 96%. Occasionally, however, PHPT cure can be challenging.A woman in her late 40s presented with bilateral renal calculi and was found to have PHPT. Following false positive imaging and three non-curative surgical procedures, removal of a supernumerary ectopic parathyroid adenoma in the aortopulmonary window via sternotomy achieved definitive cure.

An Approach to a Patient With Primary Hyperparathyroidism and a Suspected Ectopic Parathyroid Adenoma

Primary hyperparathyroidism (PHPT) is characterized by hypercalcemia driven by excess parathyroid hormone (PTH) secretion. PHPT is a common endocrine condition with a prevalence of 1 to 7 cases per 1000 adults. PHPT typically presents in the fifth or sixth decade and shows significant female preponderance. Solitary hyperfunctioning parathyroid adenomas account for 85% to 90% of PHPT cases. The remaining 10% to 15% include cases of multiglandular disease (multiple adenomas or hyperplasia) and, rarely, parathyroid carcinoma (1%). Ectopic parathyroid adenomas may arise due to abnormal embryological migration of the parathyroid glands and can be difficult to localize preoperatively, making surgical cure challenging on the first attempt. The potential existence of multiglandular disease should be considered in all patients in whom preoperative localization fails to identify a target adenoma or following unsuccessful parathyroidectomy. Risk factors for multiglandular disease include underlying genetic syndromes (eg, MEN1/2A), lithium therapy, or previous radiotherapy. In addition to multifocal disease, the possibility of an ectopic parathyroid gland should also be considered in patients requiring repeat parathyroid surgery. In this article, we use illustrative clinical vignettes to discuss the approach to a patient with primary hyperparathyroidism (PHPT) and a suspected ectopic parathyroid adenoma.