Immunocytochemical staining patterns for parathyroid hormone and chromogranin in parathyroid hyperplasia, adenoma, and carcinoma

Parathyroid glands (PGs) contain less secretory granules with presumably less stored parathyroid hormone (PTH) than many other endocrine glands. Immunocytochemical staining for PTH has been hindered by the lack of commercially available, reliable antibodies against human PTH. By treating deparaffinized tissue sections with an antigen-retrieval procedure, immunocytochemical staining for PTH and chromogranin A (CHA) was performed using commercially available monoclonal antibodies to investigate the functional activity of hyperfunctioning PGs, including chief cell hyperplasia (CCH), adenoma, and carcinoma, compared with that of normal PGs. In normal PGs, PTH and CHA immunostaining was diffusely granular in the chief cell cytoplasm, but was weak in oxyphil cells. The immunostaining in hyperfunctioning PGs was less dense in CCH, and adenomas were less intensely stained than the densely stained peripherally located normal rim. The one carcinoma case studied showed less staining at the periphery and in the mid-portion of the tumor. Thus, immunocytochemical staining for PTH and CHA provides further information on stored, immunoreactive PTH status and will improve functional analysis of hyperfunctioning parathyroid glands.