ABSTRACT
Touch preparations from surgically removed pituitary adenomas were studied by both routine staining and immunocytochemistry for all anterior pituitary hormones. The results were correlated with the histologic, histochemical, immunohistochemical and ultrastructural findings. Several features were recognized, some of them applicable in diagnosing various adenoma types: high cellularity, cell monomorphism, nuclear irregularities and heterogeneity of immunoreactivity, all major diagnostic criteria of pituitary adenoma. The presence of numerous fibrous bodies associated with nuclear pleomorphism, multinucleation and peripheral displacement of nuclei, in association with growth hormone (GH) immunopositivity, represent diagnostic criteria for sparsely granulated GH cell adenoma. The "Golgi" pattern of prolactin (PRL) immunopositivity in conjunction with the small size of cell and nucleus and the presence of microcalcifications represents diagnostic features of PRL-secreting adenoma. Cytoplasmic accumulation of hyaline material in association with peripheral distribution of periodic acid-Schiff stain and adrenocorticotropic hormone immunoreactivity is characteristic of sparsely granulated corticotroph cell adenoma. Knowledge and application of the described features may contribute significantly to the diagnostic approach to pituitary adenomas.
Subject(s)
Adenoma/pathology , Pituitary Neoplasms/pathology , Adenoma/metabolism , Adenoma/ultrastructure , Adolescent , Adrenocorticotropic Hormone/metabolism , Adult , Aged , Cell Nucleus/ultrastructure , Female , Growth Hormone/metabolism , Humans , Immunoenzyme Techniques , Male , Middle Aged , Pituitary Neoplasms/metabolism , Pituitary Neoplasms/ultrastructure , Prolactin/metabolismABSTRACT
OBJECTIVE: The aim of this study was to investigate the presence of interleukin-6 (IL-6) in human pituitary adenomas. DESIGN: Immunocytochemistry was performed in 15 cases of pituitary adenomas obtained at transsphenoidal surgery. PATIENTS: Fifteen cases of pituitary adenomas were examined; these included five GH-secreting adenomas, four prolactinomas, four ACTH-secreting adenomas and two null-cell ('functionless') adenomas. MEASUREMENTS: Each tumour was stained for the presence of IL-6 by means of the avidin-biotin-peroxidase complex (ABC) technique, and was also stained for GH, prolactin, ACTH and alpha-subunit by conventional immunocytochemistry. RESULTS: Fourteen of the 15 tumours examined, excepting one GH-secreting tumour, demonstrated clusters of IL-6 positively stained cells; the specificity of the staining was established by a significant decrease in staining in parallel sections of all tumours studied when the anti IL-6 antibody was preabsorbed with recombinant human IL-6. CONCLUSIONS: It is concluded that IL-6 immunoreactivity is present in human pituitary tumours, and is independent of the specific secretory cell product. The role of this cytokine in the pathogenesis of such tumours requires further investigation.