Ultrastructural observations on two parathyroid adenomas.

The electron microscopic observation of 2 parathyroid adenomas led to detection, in addition to elements which can also be found in nonneoplastic cells and related to the functional state, of organelles more characteristically associated with neoplastic cells. Indeed, intracytoplasmic cilia and annulate lamellae are commonly regarded as an expression of cellular atypia rather then distinctive of the adenoma cell. Moreover, our study seems to show that annulate lamellae are correlated with the hormonal synthesis more than with the rate of growth of the neoplastic tissue.