Sellar lesions associated with isolated hyperprolactinaemia. Morphological, immunocytochemical, hormonal and clinical results.

In 204 patients with sellar lesions and isolated hyperprolactinaemia we analysed and compared many different morphological, immunocytochemical, hormonal, and clinical data for a differentiation of primary (Prl produced by a tumour) and secondary (Prl elevation by PIF inhibition) hyperprolactinaemia. We found Prl-positive pituitary adenomas with primary hyperprolactinaemia in 62.7% and a secondary Prl elevation with different alterations in 37.3% (Prl-negative adenomas 28.9%, craniopharyngeomas 5%, and non-tumourous conditions 3.4%). In secondary hyperprolactinaemia the Prl values did not exceed 130 micrograms/l, higher levels indicated Prl-producing adenomas with a high probability. In patients with Prl elevation below 130 micrograms/l the clinical and sometimes the morphological analysis were not sufficient for a differentiation. Here immunocytochemical studies are necessary for a clear classification of hyperprolactinaemia.