Endocrine Abstracts

Introduction: Cushing disease (CD) is a condition due to an ACTH-secreting pituitary adenoma that is usually a microadenoma. Seldom, the lesion may be atypical by his size or his radiological aspect.

The aim of this study is to analyze the clinical and biological data of CD with atypical radiological aspect (macroadenoma or other), to compare them to those of CD with a typical radiological aspect (microadenoma) and to determine the clinical or biological factors predictive of radiological aspect.

Methods: Retrospective study of 22 patients with CD comparing clinical and biological profiles of a group of patients with CD and a pituitary microadenoma on MRI or a normal pituitary MRI=(microadenoma) group, to a group of patients with atypical MRI aspect: macroadenoma or infiltrative lesion=(macroadenoma) group.

Results: Pituitary MRI showed a microadenoma in 59% of cases and a macroadenoma or an atypical aspect in 41% of cases. Clinical profile and non specific biological anomalies were comparable in the 2 groups. Basal cortisol and cortisol after low dose dexamethasone suppressing test were also comparable in the two groups. Free urinary cortisol of 24 h and cortisol after high dose dexamethasone test were higher in the (macroadenoma) group but with no significant difference. On the other hand, mean ACTH was significantly higher in the (macroadenoma) group (154 pg/ml vs 93 pg/ml; P=0.04).

Conclusion: No clinical or biological factors can be predictive of tumoral size in CD. A particular attention should always be accorded to ACTH rate that may suggest a certain tumoral size.

Declaration of interest: The authors declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research project.

Funding: This research did not receive any specific grant from any funding agency in the public, commercial or not-for-profit sector.