ECE2019 Guided Posters Obesity (1) (11 abstracts)
1Endocrinology Unit, Department of Medicine-DIMED, University of Padova, Padova, Italy; 2Endocrinology Unit, Fondazione IRCCS Ca Granda Ospedale Policlinico, University of Milan, Milan, Italy; 3Department of Experimental Medicine, Sapienza University of Rome, Rome, Italy; 4Neurosurgery Unit, Fondazione IRCCS Ca Granda Ospedale Policlinico, University of Milan, Milan, Italy.
Background: Differential diagnosis of ACTH-dependent hypercortisolism is crucial to indicate a proper treatment and is based on CRH-, high-dose dexamethasone suppression-test (HDDST) and pituitary MRI. However, up to 50% of cases of Cushings disease (CD) present a negative MRI or a visible lesion < 6 mm. In these patients, guidelines suggest to perform bilateral inferior petrosal sinus sampling (BIPSS) in order to establish a correct diagnosis. Aim of this study was to analyze the need of BIPSS in particular in those patients with inconclusive neuroradiological examination.
Materials and methods: We performed a retrospective analysis on 122 patients (F/M 93/29, mean age 43.9±14 yrs) affected by ACTH-dependent CS followed at two tertiary care centers in Italy. CRH test and HDDST were performed on the suspect of CD and all patients were submitted to pituitary MRI; the whole cohort underwent pituitary surgery (TSS). The pituitary origin of ACTH secretion was confirmed by biochemical remission after TSS, histology and/or hypoadrenalism (at least 6 months).
Results: A negative MRI or a lesion <6 mm were detected in 74 patients (60.7%, Group A); 26 patients had a pituitary adenoma between 6-10 mm (21.3%, Group B), 22 patients a macroadenoma (18%, Group C). Patients of Group C showed higher basal ACTH levels compared to patients with microadenomas (Group A+B) (116.8±107.2 vs 50.6±29.4 ng/L, P<0.05). No difference in basal cortisol, urinary free cortisol and late night salivary cortisol levels was found. A positive response to CRH test and HDSST was recorded in 92% and 93% of cases, respectively. The diagnosis of CD was confirmed by BIPSS in 24 patients. Overall, surgical remission was achieved in 90/122 (73.8%) patients, without differences between groups. Finally, considering patients of Group A with concordant positive HDDST and CRH test, no difference in surgical outcome was found between patients who performed BIPSS and those who did not (24/35 (68.6%) without BIPPS vs 13/19 (68.4%) with BIPSS, P=1).
Conclusion: Our study confirms that CRH test and HDDST have high accuracy in differential diagnosis of ACTH-dependent CS. In patients with negative MRI or with a microadenoma <6 mm, the presence of concordant positive noninvasive tests seems sufficient to establish the diagnosis of CD. BIPSS should be reserved to discordant cases.