Endocrine Abstracts

Case history: A 63-year-old female was admitted to our hospital in January 2022 with neck swelling that had developed over five days with associated dysphagia to fluids. Biochemistry revealed severe hypercalcaemia with a corrected calcium of 3.82 mmol/l (2.20 - 2.60 mmol/l) and PTH of 78.7 pmol/l (1.6 - 6.9 pmol/l), and an associated AKI (creatinine of 174 umol/L from a baseline of 80). Ultrasound initially showed a left-sided 3 x 2 cm nodule suggestive of a large parathyroid adenoma / carcinoma. The patient subsequently developed a significant amount of bruising over the chest wall, originating from the anterior neck, consistent with haemorrhage.

Investigations: CT imaging of the neck and chest showed a 4.7 x 3.8 cm soft tissue mass posterior to the left lobe of the thyroid associated with subcutaneous inflammatory change, and an associated 7.2 x 4 cm contiguous soft tissue mass encasing the oropharynx and upper oesophagus with an appearance highly suspicious of malignancy. Due to the significantly elevated PTH level there was a high index of suspicion for parathyroid carcinoma therefore MRI imaging was performed, which showed a mass of indeterminate appearance likely to represent a parathyroid lesion (adenoma / carcinoma) with surrounding soft tissues suggestive of haemorrhage from the lesion or severe inflammatory changes. A MIBI scan identified two mildly tracer avid soft tissue nodules posterior to the upper and lower poles of the left hemithyroid, and the left soft tissue density lesion posterior to left lobe was not tracer avid, compatible with haemorrhage.

Results and treatment: Hypercalcaemia was treated with continuous IV fluids, zoledronate and cinacalcet. Neck swelling was initially managed with IV steroids. There were no airway concerns, but an NG tube was inserted to allow for feeding. Serum calcium and PTH levels fell, and she was discharged after twelve days with serum calcium in the normal range. She proceeded to have a parathyroidectomy and left hemi-thyroidectomy in August 2022 once swelling had settled and bruising resolved. Histology confirmed a benign parathyroid adenoma (left superior). At her most recent clinic follow-up in October 2022 serum calcium was normal at 2.52 mmol/l.

Conclusions and points for discussion: Haemorrhage into a large parathyroid adenoma can mimic parathyroid carcinoma with severe symptomatic hypercalcaemia, very high PTH levels and dysphagia.