The quantitative evaluation of the immunohistochemical expression of the pituitary adenomas

The aim of this study was to evaluate morphometrically the pituitary adenomas immunoexpression.

The cases of 72 patients were analyzed, who underwent transsphenoidal surgery for pituitary adenomas. Subsequently, the immunohistochemical pituitary hormone panel was applied including alpha- subunit of the glycoprotein hormones. Immunohistochemical sections were analyzed quantitatively with the help of morphometric grid. The percentage rate of the immunoexpression was calculated separately for every single hormone.

As a result, 22 monohormonal adenomas (30.56%), 21 plurihormonal adenomas (29.17%), 21 immunonegative adenomas (29.17%) and 8 unreliable cases (11.11%) were recognized. The immunopositivity for particular hormones was found as follows: PRL and GH (25% each), α-SU (22.22%), ACTH (13.89%), LH and FSH (12.5% each), and TSH (5.56%). An average percentage of immunoexpression in each positive staining groups occurred as follows: for PRL - 59.98%, for GH - 53.97%, for ACTH - 39.21%, for TSH - 25.05%, for LH - 37.3%, for FSH - 54.66%, for α-SU - 45.71.

The morphometrical method utilizing the immunoexpression index introduced in this study provided a very precise recognition of pituitary adenomas pathology. This method may limit the subjectivity of a single researcher and enable better comparison of the studies. The plurihormonality is a common phenomenon, and immunohistochemical staining for all adenohypophyseal hormones is obligatory in order to classify pituitary adenomas correctly. The awareness of an operating neurosurgeon of the importance of meticulous collecting histopathological material, especially in microadenoma cases, has essential impact on further neuropathological evaluation and possibility of immunohistochemical staining.