a 59-year - old woman was admitted to samsung medical center for suspected primary hyperparathyroidism . she had recently been experiencing constipation , irritable bowel syndrome , and bladder irritability ( such as urinary urgency ) . her biochemical levels were as follows : serum calcium , 11.4 mg / dl ( range , 8.4 to 10.2 mg / dl ) ; ionized ca , 4.9 mg / dl ( range , 3.1 to 4.8 mg / dl ) ; alkaline phosphatase , 102 u / l ( range , 42 to 98 u / l ) ; and parathyroid hormone ( pth ) , 94.0 ( range , 7.5 to 53.5 pg / ml ) . bone densitometry showed osteopenia in the left femur ( 0.719 g / cm ; t score , 1.2 ) . a chest computed tomography ( ct ) scan revealed a 15-mm soft tissue mass anterior to the ascending aorta ( fig . 1 ) . thyroid usg showed a 0.4-cm nodule in the thyroid ; however , a tc99 m sestamibi parathyroid scan of the neck and mediastinum showed an increased tracer concentration in the anterior mediastinum , which suggested the presence of active parathyroid tissue , while the same activity was not observed in the neck ( fig . the patient underwent left thoracoscopic mediastinal exploration . for this procedure , she was intubated with a double lumen endotracheal tube to enable one - lung ventilation and placed in the right lateral decubitus position . we made three ports , which were located in the anterior axillary line 6th intercostal space and mid axillary line 5th and 8th intercostal spaces . thoracoscopy revealed a mass approximately 2 cm in length in the anterior mediastinum , which was subsequently resected . thus , we removed the mediastinal mass with en bloc resection of the left - side thymus . a drop in the pth level ( from 94.0 to 6.5 pg / ml ) occurred during surgery , which suggested that all the hyperfunctioning tissue was removed . a post - surgical pathology report confirmed that the patient had a 1.5-cm parathyroid tumor . on postoperative day 2 , the chest tube was removed and there were no surgical complications . a follow - up appointment two weeks after surgery , the patient had normal serum and ionized calcium levels and no complications . surgical resection is indicated for symptomatic ectopic parathyroid adenoma , but surgery is also required for an asymptomatic patient when the serum calcium level exceeds the normal reference range by 0.25 mmol / l or 1.0 mg / dl , creatinine clearance is reduced to < 60 ml / min , bone mineral density is below 1.0 , or patients are unable to participate in appropriate follow - ups . the involvement of mediastinal ectopic parathyroid glands in primary hyperparathyroidism accounts for up to 20% of all cases . approximately 6% to 16% of the entire parathyroid gland can become ectopic in these cases , and proliferation of the tissue usually occurs in the retroesophageal space , paraesophageal space , mediastinum , intrathymic space , or carotid sheath , among other locations . because the main cause of primary hyperparathyroidism is the presence of a parathyroid tumor , surgery is the treatment of choice . although neck exploration alone yields high rates of complete recovery , reoperation is sometimes necessary when there is an ectopic lesion . therefore , accurate localization of ectopic parathyroid adenomas can increase the success rate of treatment and decrease the recurrence rate . various types of imaging tools , such as usg and ct , are used for diagnosis and localization . sternotomy and thoracotomy are the traditional methods for adenoma cases of the upper mediastinum , and cervicotomy is also a popular option . there are other approaches that can be used depending on the particular circumstances of the case . in the present case , we employed a thoracoscopic approach , which is widely used because it is minimally invasive and the lesion is located in a proper spot on the ct scan for a thoracoscopic procedure . recent attempts at surgical refinement have focused on reducing the size of the incision and minimizing surgical dissection . the reported advantages of the video - assisted techniques include small incisions and reduced soft tissue dissection . by following these procedures , highly effective and safe results additionally , since the development of the rapid pth assay , surgeons have used this technology in an attempt to confirm successful removal of ectopic parathyroid adenoma intraoperatively . because the intact form of pth has a half - life of less than 5 minutes , rapid intraoperative measurements are possible . the miami criteria for a successful parathyroidectomy require a drop of more than 50% in pth levels 10 minutes after removal of the suspected abnormal gland as compared to the highest preoperative pth level . in addition to the miami guidelines , other criteria have been developed to improve accuracy that use various combinations of preoperative , preincision , postincision , and premanipulation comparative measures . the temporal reduction in intraoperative pth ( iopth ) concentration at sequential timed intervals after removal of the suspected diseased tissue has also been suggested as a better indicator of surgical success . the iopth test may be needed in complicated cases , where preoperative imaging is unclear , or to exclude multiglandular disease . in these instances , the iopth measurement may provide useful guidance to the surgeon that no additional hyperfunctioning parathyroid tissue remains . we present our case of a successful thoracoscopic removal of the ectopic hyperfunctioning parathyroid adenoma located in the mediastinum , and suggest that this approach is a viable alternative in patients with this affliction .
ectopic mediastinal parathyroid adenomas or hyperplasias account for up to 25% of primary hyperparathyroidism cases . 
 most abnormal parathyroid glands are found in the superior mediastinum within the thymus and can be removed through a cervical incision ; however , a few of these glands are not accessible using standard cervical surgical approaches . 
 surgical resection has traditionally been performed via median sternotomy or thoracotomy . 
 however , recent advancement in video - assisted thoracic surgery techniques has decreased the need for sternotomy or thoracotomy to remove these ectopic parathyroid glands . here , 
 we report a successful case of video - assisted thoracoscopic removal of a mediastinal parathyroid adenoma .