Exp Clin Endocrinol Diabetes 2007; 115 - P01_087
DOI: 10.1055/s-2007-972343

Predictive value of pituitary histology on clinical outcome in acromegaly: A retrospective cohort study

B Steffin 1, W Saeger 2, HJ Quabbe 3, S Petersenn 4, DK Ludecke 5, J Honegger 6, M Buchfelder 7, M Reincke 1
  • 1Medizinische Klinik Innenstadt, Klinikum der Universität, Endokrinologie, München, Germany
  • 2Marienkrankenhaus, Pathologie, Hamburg, Germany
  • 3Deutsches Akromegalie-Register, Endokrinologie, Berlin, Germany
  • 4Universitätsklinikum Essen, Klinik für Endokrinologie, Essen, Germany
  • 5Universitätsklinikum Eppendorf, Hypophysenchirurgie, Hamburg, Germany
  • 6Universitätsklinikum Tübingen, Klinik für Neurochirurgie, Tübingen, Germany
  • 7Universität Erlangen-Nürnberg, Neurochirurgische Klinik, Erlangen, Germany

Immunohistochemistry is commonly performed on tumour specimen obtained during transsphenoidal surgery, but its predictive value for clinical outcome is largely unknown. The aim of the presented study was to compare clinical and biochemical outcome characteristics after surgery with histological tumour properties. This was achieved by matching data from the German Acromegaly Register with those of the Pituitary Tumour Registry of the German pituitary working group.

From 285 out of 1543 acromegalic pat. of the German Acromegaly Register (145f, 140m), data on morphological properties analyzed by a single pathologist (W.S) in the dep. of pathology, Marienkrankenhaus, Hamburg were available. Using immunohistochemistry, the density of cytoplasmatic granules, pattern of hormone expression and mitotic activity (Ki67) were analyzed. Tumours were stratified according to growth hormone (GH) and prolactin expression and Ki67 index. Clinical and biochemical parameters predicting disease outcome such as post-surgical GH and IGF-1 were analyzed. Control of acromegaly was defined as random GH <2.5µg/l and normal IGF-1. Results are presented as range, mean and SEM. Before surgery, GH and IGF-1 conc. did not differ between pat. with sparsely (n=93) and densely granulated (n=145) adenomas. However, after transsphenoidal surgery, pat. with densely granulated adenomas had significantly higher GH (0–100, 5.4±1.14 vs. 0–57, 2.98±0.917µg/l, p=0.03) and IGF-1 (94–1963, 522±14.81, vs. 12–1002, 456±36.38ng/ml, p=0.006) conc. compared to sparsely granulated adenomas. In addition, these pat. had a lower rate of biochemical control (31% vs. 54%, p=0.01). Co-expression of prolactin was found in 14% of adenomas. This was associated with higher postsurgical GH and IGF-1 (GH 10.5±8.31 vs. 3.3±1.23µg/l, IGF-1 437±149.01 vs. 348±27.3ng/ml) compared to tumours not expressing prolactin. Ki67 staining (Ki67 index <1% vs. >1%) did not have impact on clinical and biochemical variables (p=ns).

The granulation density of GH producing adenomas is a useful parameter predicting patient's biochemical outcome.