[Functional morphology and pathology of the parathyroid glands. Secretion study using tissue culture, electron microscopy, ultrahistochemistry, immunohistochemistry, morphometry and radioimmunoassay].

Abstract

The subject of this volume provides an overview on current investigational trends in parathyroid research comprising morphology, function, and regulation of function. After describing calcium homoeostasis and disorders induced by parathyroid hypo- or hyperfunction, problems associated with surgical pathology and morphological diagnostics of parathyroid tissue from hyperparathyroid patients and of tumors with paraneoplastic PTH secretion are discussed. Experimental investigations by the author using tissue culture techniques have revealed details of structure, regulation, and secretion of PTH in human and porcine parathyroid glands drawing special attention to the secretory and morphological differences between normal and adenomatous parathyroid tissues. The combined application of methods available in morphology (electron microscopy, immunohistochemistry, ultrahistochemistry, morphometry) and biochemistry (radioimmunoassay, gel-filtration) allows the direct correlation of structure and function in the organ culture system, resulting in a functional morphology and pathology of parathyroid glands. Clinical pathology of primary hyperparathyroidism. The quantitative distribution of 220 operatively obtained parathyroid tumors consisting of 90% adenomas, 8.6% hyperplasias, and 1.4% carcinomas is in agreement with published data of the literature. The intraoperative discrimination between parathyroid and non-parathyroid tissue, necessary for successful search, is a prerequisite for the adequate therapy. A summary of macroscopical criteria will be helpful in improving the intraoparative first-look diagnostics. Problems arising with rapid intraoperative frozen section diagnostics and histological discrimination between adenoma, hyperplasia, and carcinoma are described. Functional morphology and pathomorphology of the parathyroid glands Cellular distribution of PTH and calcium. The chief cells of normal parathyroid glands often cannot be distinguished from those of adenomas if only conventional light- or electron microscopy are applied. However, by using immuno- and ultrahistochemistry evidence was established that adenomatous chief cells contain less PTH than normal chief cells, and that tumor cells are in an activated state. The intracellular calcium content of tumor cells was distinctly lower than in normal parathyroid chief cells, although in primary hyperparathyroidism the extracellular calcium concentration is elevated. The increased amounts of extracellular calcium finds a correlation in the accumulation of calcium deposits in the intercellular space and at the plasmalemma.(ABSTRACT TRUNCATED AT 400 WORDS)