A Surgical Management of Mediastinal Parathyroid Adenoma: A Regional Experience in Malaysia

Abstract

Primary hyperparathyroidism (PHPT) usually presents with symptoms of hypercalcemia which is due to excessive secretion of parathyroid hormone (PTH). Surgical removal of the secreting tumor either adenoma or hyperplasia remains the mainstay of treatment. Around 2% to 25% of the lesions are located in the mediastinum. We reviewed our institution's surgical treatment and approach to mediastinal parathyroid adenoma (MPA). We retrospectively reviewed the demography, comorbidities, clinical presentation, surgical approach, and outcome for patients in our institution who underwent surgery for MPA from September 2019 until August 2023. All patients with MPA who underwent surgery were included in the review. The surgical approaches used were both video-assisted thoracoscopic surgery (VATS) and median sternotomy. There were three patients with PHPT due to MPA who underwent surgery. Out of the three patients, two were female. The mean age was 48.6 years old, ranging from 16 to 66 years old. All of them presented with PHPT with a raised mean serum calcium level of 3.52 mmol/L (range: 2.84-4.38 mmol/L) and a mean PTH or intact PTH (iPTH) level of 274.6 pmol/L (range: 8.87-695 pmol/L). Ultrasound of the neck was performed for all the patients before further investigations were done to look for the ectopic parathyroid gland. Computed tomography (CT) of the thorax showed mediastinal parathyroid mass in all the patients with an average size of 2.4 x 2.1 x 2.3cm (range: 1.3-3.8cm), which showed uptake in 99mTc-hexakis-2-methoxyisobuthylisonitrile (Tc99m-MIBI) scintigraphy. VATS was performed for two cases and an upper partial sternotomy was performed for one patient. Postoperatively, iPTH and serum calcium levels were reduced significantly for all patients. There were no post-operative complications in our study. Comprehensive diagnostic imaging and surgical planning are important for the localization of MPA. In our review, all cases were promptly diagnosed and underwent surgery without complication.

Keywords: ectopic; mediastinum; parathyroid adenoma; primary hyperparathyroidism; video-assisted thoracoscopic surgery (vats).

Figure 1. Computed tomography (CT) thorax of Case 1 (A) showed a hypodense lesion (arrow) at the 2R-4R region. Contrasted CT thorax of Case 2 (B) showed a hyperdense lesion (arrow) anterior to ascending aorta. Contrasted CT thorax of Case 3 (C) showed a heterogenous lesion (arrow) located between the right brachiocephalic vein and innominate artery.

Figure 2. Tc99m-MIBI (methoxyisobutylisonitrile) scintigraphy of Case 1 (A), Case 3 (C), and single-photon emission computed tomography imaging (SPECT) scan of Case 2 (B) exhibited the mediastinal parathyroid adenomas (arrow).