Minimally invasive thoracoscopic parathyroidectomy for an ectopic mediastinal parathyroid adenoma
A 33-year-old lady presented with symptoms of bony pains for the past 2-3 years. Further history and clinical examination were unremarkable. On evaluation, her calcium was found to be 10.8mg/dl (normal range, 8.5-10.1 mg/dl). Biochemical diagnosis of primary hyperthyroidism was made after detailed evaluation.
However standard localization tests including an ultrasound neck and a Technitium -99 sestamibi scan could not locate the parathyroid lesion. A possibility of an ectopic location of the parathyroid lesion was considered. She then underwent C11-Choline PET-CT, which showed a focal choline uptake in the anterior mediastinum below the angle of Louis. The corresponding CT scan showed a 1×0.8cm lesion at the level of the ascending aorta.
A thoracoscopic excision of the mediastinal parathyroid adenoma was planned by the endocrine surgeon and the cardiothoracic team. Three ports were used one 10mm and two 5mm. Single lung ventilation with a double-lumen endotracheal tube was used. The right thymus was dissected off the ascending aorta, arch of the aorta and inferior to the brachiocephalic vein. The parathyroid lesion was taken out intact and was found to be within the right thymus.
Intraoperative PTH monitoring was used to determine successful excision of the lesion. The pre-incision Intra-operative parathyroid hormone was 255 pg/ml. The 15 minutes post excision PTH value dropped to 25 pg/ml. A frozen section biopsy of the excised specimen showed a parathyroid adenoma located within the thymic tissue. Postoperatively, the calcium value decreased to 9.1mg/dL. The patient’s postoperative period was uneventful, and the patient was discharged on the second postoperative day.
The most frequent cause of hypercalcemia in the outpatient setting is primary hyperparathyroidism. The standard treatment for PHPT is surgical excision via a cervical approach. However, in about 1-2% of the cases, the ectopic mediastinal parathyroid tissue is not accessible through the neck. Precise preoperative localisation of the ectopic parathyroid adenoma is vital for successful surgical resection.
Dr Siddhartha Chakravarthy, MS, MCh (Consultant Endocrine & Breast Surgeon), Apollo Hospitals, Jubilee Hills, Hyderabad
Dr AGK Gokhale, MS, MCh (Consultant Cardiothoracic Surgeon), Apollo Hospitals, Jubilee Hills, Hyderabad
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