A case report of a functioning mediastinal parathyroid cyst with no 99mTc-MIBI uptake. (2018)

• Record Type: Journal Article
• Authors: Uchida, Naotaka; Yoshida, Manabu; Matsui, Yasuki; Notsu, Takeshi
• Is Part Of: International journal of surgery open. Volume 12(2018)
• Page Start: 5
• Page End: 8
• Publication Date: 2018
• Subjects: Parathyroid cyst -- Mediastinal mass -- Hyperparathyroidism -- 99mTc-MIBI scintigraphy -- Case report; Technetium-99m-methoxyisobutylisonitrile 99mTc-MIBI -- calcium Ca -- phosphate P -- parathyroid hormone PTH; Surgery -- Periodicals; 617.005
• DOI: 10.1016/j.ijso.2018.05.001
• Languages: English
• ISSNs: 2405-8572

Abstract

Abstract: Introduction: Functioning mediastinal parathyroid cysts are extremely rare. Technetium-99m-methoxyisobutylisonitrile ( 99m Tc-MIBI) scintigrams usually helps to localize parathyroid lesions, but we report a case with no MIBI uptake. Presentation of case: A 79-year-old woman with lower extremity edema and dysphagia was referred to our hospital. Her blood calcium (Ca) level was 11.1 mg/dl, and the intact parathyroid hormone (PTH) level was 132 pg/ml. Computed tomography showed a 3.5 cm solid nodule in the right thyroid lobe and a 5.4 cm cystic mass extending to the mediastinum. The 99m Tc-MIBI scintigram showed abnormal uptake in the thyroid nodule but no uptake in the mediastinal mass. The diagnosis was a thyroid nodule in the right lobe, primary hyperparathyroidism and a mediastinal mass. Under general anesthesia, the thyroid nodule and the mediastinal mass were resected via a cervical incision. The right lower parathyroid gland was resected because it measured about 1 cm and had the dark red color of a parathyroid adenoma. The pathological diagnoses were adenomatous goiter, normal parathyroid gland and mediastinal parathyroid cystic adenoma. The histopathological examination of the mediastinal mass showed a uniform population of parathyroid cells. The postoperative serum Ca and intact-PTH levels were normal. There has been no relapse. Discussion and Conclusion: Patients with parathyroid cysts sometimes have negative 99m Tc-MIBI scans. We should consider a parathyroid cyst when a mediastinal cystic mass is demonstrated. Surgical resection is thought to be the optimal therapeutic choice for mediastinal parathyroid cysts irrespective of functioning because mediastinal parathyroid cysts are large and produce compressive symptoms. Highlights: Functioning mediastinal parathyroid cysts are extremely rare. Parathyroid cyst sometimes is associated with a negative 99m Tc-MIBI scan, and the result may mislead us. Surgical resection may be the optimal therapeutic choice for mediastinal parathyroid cysts irrespective of functioning.