Cystic parathyroid adenoma: Primary hyperparathyroidism without 99m Tc-MIBI uptake.

Cystic parathyroid adenoma is a rare disease (<0.01% of all cervical masses) that associates primary hyperparathyroidism in 9% of cases. Parathyroid scintigraphy is essential for its diagnosis with uncommon false negative results. Hybrid SPECT/CT equipments allow a more accurate diagnosis. Functional cystic parathyroid adenomas are surgically treated. A case of a 64-year-old woman with diagnoses of hyperparathyroidism and a cystic parathyroid adenoma without uptake in scintigraphy is described.