Endocrine Abstracts

JOINT3811

Introduction: Acromegaly is a rare disorder resulting from chronic hypersecretion of growth hormone (GH), typically due to a pituitary adenoma. Conversely, non-functioning pituitary adenomas (NFPAs) are among the most common subtypes of adenohypophyseal tumors, characterized by the absence of clinically significant hormone secretion. Data regarding gender distribution and mean age at diagnosis for these conditions remain inconclusive.

Aim: The study aimed to assess the differences in gender distribution, age, tumor volume, and hormonal immunochemical profiles (IHC) between patients with acromegaly and NFPA at diagnosis.

Methods: We retrospectively analyzed 81 patients diagnosed with acromegaly and 76 patients with NFPAs referred to our Clinic’s Endocrinology and/or Neurosurgery Units between 2018 and 2019. Immunohistochemical analysis of adenohypophyseal hormone expression was available in tumor tissue samples from 53 patients with acromegaly and 29 with NFPA.

Results: Patients with acromegaly were diagnosed at a younger age than those with NFPAs (median [IQR]: 43 [39–56] years vs. 50 [40–63] years; P = 0.034), while no significant difference in gender distribution was observed between the groups. The median tumor volume in patients with NFPAs (3.8 [1.4–8.4] cm³) was significantly larger than that in patients with acromegaly (1.4 [0.7–4.8] cm³; P = 0.004). Immunohistochemical analysis revealed that adenomas in acromegalic patients were predominantly plurihormonal, with growth hormone and prolactin being the most frequently co-expressed hormones. In contrast, NFPAs showed most commonly negative hormonal staining. Among patients with acromegaly, males were diagnosed at a younger age than females (median [IQR]: 42.0 [39–50] years vs. 47.0 [38.5–60.5] years; P = 0.041). Interestingly, in patients with NFPA, both genders showed no significant differences regarding median age at diagnosis and tumor volume.

Conclusion: Our findings indicate that male patients with acromegaly are diagnosed at an earlier age than females, despite both having no significant differences in pituitary tumor volumetry. This may reflect an earlier onset or more prominent presentation of disease-related signs in males. Additionally, positive immunostaining for growth hormone and prolactin co-expression was a distinctive feature of pituitary tumor cells in patients with acromegaly.