Giant functioning mediastinal parathyroid cyst: an unusual cause of exertional dyspnea and mild dysphagia

An unusual etiology of hyperparathyroidism: robotic-assisted resection of a giant functional intrathymic parathyroid cyst

Parathyroid cysts (PCs) are relatively rare entities, with an even smaller proportion that functionally produce parathyroid hormone (PTH). Given associated hypercalcemia, often symptomatic, as well as potentially related osteoporosis and/or nephrolithiasis, resection of these functional cysts is often indicated. This case report details the management course for a patient who presented with primary hyperparathyroidism and was ultimately found to have a functional intrathymic PC. During initial workup, 4-dimensional computed tomography (4D-CT) of the neck demonstrated enlarged left upper and right lower parathyroid glands; however, the patient's hyperparathyroid state persisted even after bilateral neck exploration and resection of these two glands. Subsequent postoperative imaging of the mediastinum revealed a large (11 cm) thymic cyst. The patient consequently underwent uneventful robotic-assisted thoracoscopic excision of the mediastinal cyst. Intraoperative blood PTH levels dropped from 734 pg/mL preoperatively to 86 pg/nL 10 minutes following resection, consistent with surgical cure by the Miami Criteria. At two months postoperatively, the patient's serum total calcium (STC) was normal at 9.2 mg/dL. Final surgical pathology noted a 15-gram parathyroid gland, with cystic degeneration. As the robot becomes further integrated into the everyday practice of thoracic surgery, we believe this approach offers advantages over conventional video-assisted thoracoscopic surgery (VATS) for mediastinal resections. Advantages include better visualization and finer, more precise dissection, especially important in this case, given the proximity of vital structures and the small, but real, risk of parathyromatosis associated with intraoperative cyst rupture.

Parathyroid cysts: A review of 359 patients reported in the international literature

BACKGROUND

Parathyroid cysts are lesions that represent 1-5% of neck masses. They are subdivided into two categories: functioning and non-functioning.The aim of the present review is to give a detailed account of all reported cases of parathyroid cysts in the literature and to analyze statistically the available data.

METHODS

A bibliographic research was performed from 1905 until 2016. A database with the patients' characteristics was made and analyzed statistically.

RESULTS

A total of 218 articles were found, reporting 359 cases of cysts. Mean age of patients was 49.24 y/o and the male/female ratio was 1:1.85. The most common locations were left thyroid lobe (113/358 patients, 31.6%), and superior mediastinum (69/358 patients, 19.3%), while the most common symptoms were neck mass (148/355 patients, 41.7%), compressive symptoms (73/355 patients, 206%) and hyperparathyroidism (62/355 patients, 17.5%). Non-functioning cysts were more frequent (220/357 patients, 61.6%). Regarding dimensions, mean diameter was 4.88 cm. Ultrasound and FNA are used for their diagnosis, while cystic fluid analysis may help the differential diagnosis. Recurrences were mentioned in 27/97 patients (27.8%) with available data. No deaths due to parathyroid cysts were mentioned in the literature.

CONCLUSION

Parathyroid cysts should be taken into consideration in case of parathyroid dysfunction or asymptomatic neck mass. The surgeon's careful manipulations on the cyst are crucial for a definitive treatment.

Robotic resection of a mediastinal parathyroid cyst

Mediastinal parathyroid cysts (PC) are rare, benign lesions, reported in fewer than 150 cases worldwide. Although most are asymptomatic and discovered incidentally on imaging, symptoms of dyspnea, dysphagia, hoarseness, palpitations, hypercalcemia, and innominate or jugular venous thrombosis have been reported. Sternotomy or thoracotomy has traditionally been the approach used to resect mediastinal PCs. We describe the first reported case of a robot-assisted resection of a mediastinal PC.