Endocrine Abstracts

Background and aim: Acromegaly is mostly due to a somatotropic adenoma. Regarding its insidious nature, this adenoma is often revealed at an invasive stage. This study aims to describe the radiological specificities of somatotropic adenomas at the time of diagnosis

Patients and methods: We conducted a retrospective study at the Endocrinology department of Hedi Chaker University Hospital, Sfax, Tunisia. We involved 29 patients diagnosed with acromegaly, whose clinical, biochemical, and imaging peculiarities were collected from medical charts.

Results: The mean age at diagnosis was 45.8±12.4 years with a male predominance (51.7%). The majority of patients (60%) presented with symptoms evolving 5 years before the diagnosis. The reasons for consultation were dominated by a pituitary tumor syndrome (30%) or acrofacial dysmorphia (16.6%). A hypothalamic–pituitary MRI was performed in all patients. Somatotropic macroadenomas were predominant, noted in 82.8%. The frequency of microadenomas did not exceed 17.2%. The mean tumor size was 23±10.5 mm. The majority of adenomas (44.8%) were between 10 and 20 mm. Two patients had a giant adenoma (46 mm and 50 mm). A T1 hypo-signal or iso-signal was observed in 47.1% and 52.9% of patients, respectively. On T2-weighted sequences, the adenoma appeared as iso-signal in 44.4%, more rarely as hypo- (27.8%) or hyper-signal (27.8%). Pituitary apoplexy was found in 2 cases. The adenoma was invasive in 48.3%. This invasion was at the expense of the cavernous sinus (20.7%), the supra-sellar cisterns (31%) or the sphenoidal sinus (6.9%).

Discussion: Somatotropic adenomas are classically invasive macroadenomas. Their spontaneous signal is variable but a heterogeneous appearance is frequent, particularly clear in T2. Some studies suggest that a hypointense T2 appearance correlates with high secretory activity (densely granulated cells) and is predictive of a better biological response to somatostatin analogues.