Yuki Ozawa

Occurrence of the parathyroid cyst in golden hamsters.

Parathyroid cyst is a rare lesion, but has clinical significance because of its ability to mimic a thyroid mass and its association with hyperparathyroidism. The occurrence and morphology of parathyroid cysts in golden hamsters from neonatal to senile periods were investigated using light and electron microscopy. The results demonstrate the presence of chief cell cysts in the parathyroid glands of 5-day-old hamsters. Some chief cells lining the cyst wall showed mitosis and apoptosis. The existence of chief cell cysts may represent the rapid proliferation of the parathyroid chief cells in 5-day-old hamsters. Ciliated cysts were observed in the parathyroid glands of 5-day-, 1- and 3-month-old hamsters. Three cell types were distinguished in the wall of the ciliated cyst: Ciliated, mucous and basal cells. Ciliated cysts possessed the features of the pharyngeal epithelia without endocrine cells and may arise from embryological remnants of pharyngeal pouches in the neck undergoing cystic degeneration and entrapping portions of parathyroid tissue. The frequency of parathyroid cysts decreased with age.