Bilateral giant parathyroid adenoma in the absence of multiple endocrine neoplasia type 1.

Bilateral giant parathyroid adenoma in the absence of multiple endocrine neoplasia (MEN) type 1 is extremely rare and literature on this subject is limited. A 79-year-old man presented with acute kidney injury secondary to hypercalcaemia. Blood test results indicated primary hyperparathyroidism. Ultrasonography revealed bilateral parathyroid adenomas measuring 19.4mm x 19.5mm x 18.8mm (left) and 15.2mm x 18.3mm x 19.6mm (left) whereas on computed tomography, the measurements were 31mm x 20mm (left) and 30mm x 14mm (right). Intraoperatively, giant adenomas measuring 50mm x 25mm x 12mm (left, weighing 8.101g) and 48mm x 22mm x 10mm (right, weighing 7.339g) were identified and excised. Parathyroid hormone level dropped from 44.6pmol/l preoperatively to 8.9pmol/l postoperatively (normal range 1.3-7.6pmol/l). The patient was discharged with no complications. We report a rare phenomenon where bilateral giant parathyroid adenoma occurred in the absence of MEN type 1. It highlights the importance of cross-sectional imaging in delineating the anatomy of adenomas as their size can be grossly underestimated by ultrasonography alone.