[Intraoperative extemporaneous examination of the parathyroid gland: what is the role of the pathologist in parathyroid pathology?].

Hyperparathyroidism (HPT), once considered a rare disease, is nowadays observed and diagnosed more frequently. Consequently, surgical treatment of HPT is often performed with good therapeutic results. The success of parathyroid surgery depends mainly on the accuracy of histopathologic diagnosis through intraoperative examination of frozen tissue specimens. Yet, parathyroid gland pathology is very complex and some of its topics even controversial. Terminology and clinico-pathological concepts in this field are constantly changing and even basic characteristics such as weight, stromal fat content and "normal " histologic patterns of these glands are still actively discussed. The pathologist must often determine, merely by studying a small bioptic specimen, not only the parathyroidal (or non-parathyroidal) origin of the examined tissue, but also the histological "normal" or "abnormality" of the tissue. In carrying out his work the experienced pathologist takes on an important task and responsibility in distinguishing between normal, early hyperplastic (asymmetric), hyperplastic or adenomatous parathyroid glands. New diagnostic technical approaches (such as Electron Microscopy, intracellular fat morphometric evaluation, parenchymal cell mass study by density gradient, etc.) enhance the possibility of reaching a reliable pathologic diagnosis, but they do not solve all the present problems and sometimes can even lead the pathologist astray. Presently the diagnosis and treatment of primary HPT should be considered an open and current problem inasmuch as definite criteria to be followed in distinguishing between normal or single enlarged glands microscopically are still lacking. Neither the degree of accuracy of intraoperative frozen section examination during parathyroid surgery nor the possibility of misleading observations in such a study has been fully evaluated. A close cooperation between the pathologist and head and neck surgeon is of utmost importance to assure the best therapeutical results obtainable from parathyroid surgery in HPT.