Comparison of the Serum Hormone Levels and Histological Findings in Pituitary Adenomas

Abstract

(a) there is no close correlation between the hormone granules detected in the pituitary adenoma cells - by light microscopic, immunocytochemical and electron microscopic methods - and the serum hormone levels, their response to TRH; (b) in hormonally active adenomas the immunocytochemical as well as the ultrastructural findings could be negative; (c) in one disease more hormones could give an immunopositive reaction; (d) in any types of investigated adenomas the TSH immunopositivity was always accompanied by PRL immunopositivity (6 cases); (e) the size and the clinical (serum) or cytological hormone activity of the adenomas were independent of one another; (f) the basal serum hormone level shows the hormonal activity of the pituitary adenoma best of all.

Digital analysis of hormonal immunostaining in pituitary adenomas classified according to WHO 2017 criteria and correlation with preoperative laboratory findings

“…Clinical, neuroimaging, and laboratory findings from our patients were similar to those reported in previous studies. 1,2,5,9,11,13,14,26,30,32,33,36 Additionally, Pit-1, Tpit, and SF-1 immunostaining patterns were nuclear, whereas GH and ACTH immunostaining results presented diffuse cytoplasmic staining, in accordance with what has been reported by other investigators. 3,4,13,22,25,26,30,40 Only GH and ACTH were immunohistochemically analyzed in the present study, because we did not include data from patients who presented features suggestive of the oversecretion of other pituitary hormones.…”

“…1,2,5,9,11,13,14,26,30,32,33,36 Additionally, Pit-1, Tpit, and SF-1 immunostaining patterns were nuclear, whereas GH and ACTH immunostaining results presented diffuse cytoplasmic staining, in accordance with what has been reported by other investigators. 3,4,13,22,25,26,30,40 Only GH and ACTH were immunohistochemically analyzed in the present study, because we did not include data from patients who presented features suggestive of the oversecretion of other pituitary hormones. Moreover, because we used Pit-1 to identify lesions from acromegalic patients, we did not further differentiate the other lineages that were Pit-1 immunopositive (somatotrophs, lactotrophs, mammosomatotrophs, and thyrotrophs).…”

“…These results might be due to the fact that immunostaining for a hormone may reflect a transitory state of intracellular storage and not secretory activity. [12][13][14][15]37 Similarly, a correlation between GH and PRL immunostaining and tissue concentrations of those hormones assessed by radioimmunoassay was reported in rat PAs. 22 Therefore, immunohistochemical analysis does not evaluate PA endocrine activity at a given time, but rather tissue storage, which could account for the fact that we found no correlation between lesion expression and peripheral levels of hormones.…”

“…The opposite finding, of no correlation, has also been described. 5,12,13,37 In one series, patients presenting with the highest ratios of PRL immunopositivity also showed the highest PRL serum levels. 35 A correlation between immunostaining for GH and its serum levels was reported by some research groups and not observed by others.…”

“…35 A correlation between immunostaining for GH and its serum levels was reported by some research groups and not observed by others. 13,30 In addition, a correlation between the expression of ACTH and the corresponding blood levels in ACTH-secreting PAs has not been identified. 12 Finally, there have been reports on the lack of immunopositivity for GH in PAs from patients with acromegaly.…”