Importance of careful Tc-MIBI interpretation in patients with thyroid cancer and primary hyperparathyroidism

A 39-year-old woman presented to our clinic with incidentally detected hyperglycemia. Her medical history revealed no specific illness except for a previously diagnosed 2 cm sized thyroid nodule which was diagnosed benign nodular hyperplasia by ultrasound (US) guided fine-needle aspiration (FNA) biopsy for 3 years ago. Laboratory findings show hyperglycemia, hypercalcemia, hypophosphatemia, and increased parathyroid hormone (PTH) level. So, we perform neck US and 99mTc-sestamibi scintigraphy (Tc-MIBI) for primary hyperparathyroidism (PHPT) evaluation. Neck US showed a 2 cm illdefined isoechoic nodule in the left thyroid that had previously existed (Fig. 1A). Tc-MIBI showed a single focus of hot uptake (Fig. 1B) and pathology of the left mass after lumpectomy revealed a minimally invasive follicular thyroid carcinoma and uncorrected hypercalcemia (Fig. 1C). Follow-up Tc-MIBI showed a new increased focal uptake below the lower pole of the right thyroid (Fig. 2) which was confirmed parathyroid adenoma by reoperation. The serum PTH Importance of careful Tc-MIBI interpretation in patients with thyroid cancer and primary hyperparathyroidism