Parathyroid anatomy in hyperplasia.

Pathologically enlarged parathyroid glands offer the surgeon a vital medium for studying parathyroid anatomy. The advantages include gland magnification, rapid-section diagnosis to aid dissections, and postoperative clinical and laboratory responses to check for "missed" or supernumerary glands. In this series, each of 71 patients had at least four hyperplastic glands. Both mediastinal and intrathyroidal glands occurred in nine instances (13%), supernumerary glands in eight (11%), and ectopic neck glands in seven (10%). In total, anomalous parathyroid glands occurred in almost half (46%) of these patients with parathyroid hyperplasia.