Impact of pituitary adenoma histological subtype on remission and disease control in acromegaly.

Abstract

Acromegaly results from different histological subtypes of pituitary adenomas, mainly pure GH-secreting adenomas (densely or sparsely granulated) and GH-PRL adenomas. Data on the impact of histological subtype on surgical outcomes in acromegaly remain limited. This study aimed to assess the impact of pituitary adenoma histological subtype on acromegaly remission at 3 months and last follow-up, as well as on disease control. We conducted a retrospective, single-center study of 128 patients who underwent surgery for GH or GH-PRL adenomas, without prior medical therapy, between 2012 and 2022. Among the adenomas, 61% were pure GH (39% DG, 22% SG) and 39% were GH-PRL. Compared to DG adenomas, SG adenomas were diagnosed at a younger age (p = 0.006), were larger (p = 0.022), expressed more SST5 (p = 0.032) and less SST2 (p < 0.001). GH-PRL adenomas were more frequently p53-positive (p = 0.024), had a higher mitotic count (p = 0.017) than DG adenomas and expressed more SST2 than SG adenomas (p < 0.001). The remission rates for DG, GH-PRL and SG adenomas were not significantly different at 3 months (60%, 58% and 43%, p = 0.337), or at last follow-up (80%, 74% and 57%, p = 0.091), nor was disease control at last follow-up (94%, 96% and 82%, p = 0.115) after 42 months. Histological subtype was not significantly associated with remission or control of acromegaly. Although a trend toward lower remission rates was observed in SG adenomas, its clinical impact appears limited.