Atypical primary hyperparathyroidism due to parathyroid lipoadenoma: a case report.

Parathyroid lipoadenoma is a very rare cause of primary hyperparathyroidism. Preoperative imaging techniques often fail to detect such lesions, and even during surgery they can be misinterpreted just as fat tissue. A 62-year-old woman clinically monitored for primary hyperparathyroidism, with hypertension and a left nephrectomy for hydrouretheronephrosis caused by recurrent kidney stones. A neck ultrasound showed a nodule consistent with left parathyroid of 9 × 5 mm, which was not confirmed on single-photon-emission computed tomography/computed tomography (CT) scan. On surgery, a voluminous lesion with adipose appearance and texture was removed. Frozen sections and intraoperative parathyroid hormone (PTH) confirmed such lesion to be a parathyroid lipoadenoma. Parathyroid lipoadenomas are difficult to localize preoperatively. Sometimes they can be seen by ultrasound scan as hyperechoich lesion, but scintigraphy and CT often fail to identify them. Only the awareness of such lesions and the use of intraoperative PTH can avoid unnecessary extensive cervical exploration.