Technetium-99m sestamibi single-photon emission computed tomography/computed tomography (99mTc-sestamibi SPECT/CT) is a mainstay of the pre-operative localization of parathyroid lesions. We report here the case of a 30 year-old woman with a fortuitously discovered 2 cm cervical mass for which a parathyroid origin was originally suspected due to its retro-thyroidal localization and a personal history of nephrolithiasis. Normal serum calcium and parathyroid hormone (PTH) levels excluded primary hyperparathyroidism, raising suspicion of a non-functional parathyroid adenoma, and SPECT/CT imaging showed that the mass was 99mTc-sestamibi-avid. Fine-needle aspiration (FNA) was performed; cytology was non-diagnostic but the needle washout was negative for thyroglobulin, calcitonin and PTH, arguing against a thyroidal or parathyroidal origin of the mass. Core needle biopsy revealed a schwannoma, ostensibly originating from the recurrent laryngeal nerve; upon surgical resection, it was finally found to arise from the esophageal submucosa. This case illustrates the fact that endocrinologists, radiologists, nuclear medicine, head and neck, and other specialists investigating patients with cervical masses should be aware that schwannomas need to be considered in the differential diagnosis of focal 99mTc-sestamibi uptake in the neck region.

Ectopic mediastinal parathyroid is a common cause of recurrent and persistent hyperparathyroidism. Patients with recurrent and persistent hyperparathyroidism have elevated parathyroid hormone, which results in bone, vascular, and soft tissue abnormalities. While CT and MRI can be used to investigate ectopic parathyroid tissue, nuclear medicine Technetium-99m Sestamibi scan is the preferred method of imaging with sensitivity of 80%-90% and specificity of nearly 90%. Once identified, ectopic mediastinal parathyroid is treated with surgical resection though less invasive methods have gained popularity. We present a case of a 62-year-old female with recurrent secondary hyperparathyroidism that was localized to an ectopic mediastinal parathyroid gland.

UNASSIGNED: Parathyroid carcinoma is exceedingly rare. This cancer does not metastasize in a predictable manner and has in fact been noted to spread both hematogenously and lymphatically. There are currently no cases in the literature that report metastasis to a contralateral level II lymph node.
UNASSIGNED: We report a case of recurrent parathyroid carcinoma in which the patient underwent several surgeries for right-sided parathyroid carcinoma and hyperparathyroidism, including 2 redo parathyroidectomies, 4 neck dissections, and auto transplantation and re-excision of the autotransplanted tissue. Almost a decade after initial surgery, parathyroid hormone (PTH) levels rose significantly, but nuclear medicine (NM) sestamibi scan, positron emission tomography-computed tomography (PET-CT), and ultrasound (US) could not identify the source of recurrent disease. Finally, neck US revealed a suspicious contralateral level II lymph node; fine needle aspiration (FNA) of the lymph node revealed parathyroid tissue, and PTH aspirate noted an elevated PTH washout. After left lateral neck dissection, pathology confirmed recurrent metastatic parathyroid carcinoma, and serum calcium and PTH levels improved. This case was further complicated by chronic kidney disease and pT1N0M0 colon cancer, all before the age of 45.
UNASSIGNED: In cases where a sestamibi scan is not able to localize a metastatic focus in a patient with known parathyroid carcinoma, FNA and PTH washout are important secondary studies.