The parathyroid glands are known to play a role in calcium regulation, and when the function of these glands becomes deranged, the symptoms that can be debilitating can ensue. When a high clinical suspicion of hyperparathyroidism combined with elevated levels of intact parathyroid hormone (PTH) and calcium are detected, a 99mTc-sestamibi single-photon emission computed tomography/Computed Tomography (SPECT/CT) is traditionally requested. The sensitivity of this imaging for localizing a single adenoma is particularly high, but its sensitivity decreases when multiple adenomas are present. This case report aims to establish the utility of 18F-Choline Positron Emission Tomography/Computed Tomography (PET/CT) in determining multiple adenomas.

We are presented with a case of an 85-year-old known diabetic and osteoporotic female who had neurological symptoms of disorientation, drowsiness and episodes of body weakness for 1 month. Diagnostic workup revealed incidental findings of hypercalcemia with a serum calcium level of 2.74 mmol/L (1.09-1.30 mmol/L), and an intact Parathyroid hormone (intact PTH) of 982.7 pg/mL (18.50-88.00 pg/mL). During admission, a 99mTc-sestamibi SPECT/CT was done; however, results were inconclusive. Hence, she underwent 18F-Choline PET/CT scan, revealing parathyroid adenomas with a mean diameter of 0.6 to 1.5 cm in both superior poles of the parathyroid gland. She then underwent focused parathyroidectomy of the bilateral upper poles with intraoperative intact PTH monitoring.

Intraoperatively, there was significant reduction of intact PTH from a baseline pre skin intact PTH level of of 2,505 pg/mL to 151.8 pg/mL 10 minutes after the removal of the culprit parathyroid glands. Normalization of calcium to 1.12 mmol/L from baseline was documented post-operatively, with improvement of symptoms from baseline. She was noted to be fully awake and oriented after recovery from anesthesia with no immediate post operative complications. During the hospital admission, the patient remained asymptomatic. She was eventually discharged improved with no recurrence of neurological symptoms and no recurrence of hypercalcemic episodes.

This case highlights the higher sensitivity of 18F-Choline PET/CT scan in determining multiple parathyroid adenomas compared to traditional first-line imaging procedures. This has the potential to eventually replace 99mTc-sestamibi scans, paving the way for improved preoperative planning and better patient outcomes.