Subtypes of Pituitary Adenomas and Prediction of Remission in Acromegaly

Different pathologic subtypes of pituitary adenomas do not have a major predictive role in estimating remission outcomes in patients with acromegaly, according to a study in BMC Endocrine Disorders.

Researchers conducted a retrospective review of 89 consecutive surgeries for growth hormone–producing pituitary adenomas from February 2015 to January 2021. All surgeries were performed at a single tertiary referral center in Iran, and all patients had at least 3 months of follow-up after surgery.

A total of 71 patients (mean age, 41.4±10.7 years; 62% female) were included in the analysis and grouped according to pathologic subtypes of pituitary adenomas. The single staining group included 48 patients (34 had densely granulated [DG] and 14 had sparsely granulated [SG] pituitary adenomas), and 23 patients had dual staining pituitary adenomas.

Remission rates were 62.5% (30/48) in the single staining group and 52.2% (12/23) in the dual staining group. No statistically significant difference was found between the single and dual staining groups (P =.407), and 40.8% (29/71) of patients did not achieve remission.

Postoperative remission was 1.53-fold higher after surgery in the single staining adenoma group compared with the dual staining group, but no statistical difference occurred between them (P = .409). Densely granulated adenomas were associated with 2-fold more remission rates compared with the other groups (P > .05).

In the multivariate analysis, cavernous sinus invasion reduced disease remission by 91% (95% CI, 0.01-0.67) and 1-day postoperative growth hormone for each nanogram per milliliter reduced disease remission by 64% (95% CI, 0.19-0.69).

No statistically significant difference was found regarding medical responsiveness among the DG, SG, and dual staining groups (P = .124).

Study limitations include the retrospective design and small sample size. Researchers also acknowledged the type of cell population (mammosomatotroph or mixed-somatotroph-lactotroph) in dual staining adenomas was not determined separately by electronic microscope because these two subtypes may have different behavior and response to treatment.

“Further studies with more accurate tools such as electron microscopes as well as newer molecular markers are needed to [determine] the prognostic role of the pathology on the treatment response in acromegaly patients,” the study authors concluded.

Reference

Dehghani M, Davoodi Z, Bidari F, et al. Association of different pathologic subtypes of growth hormone producing pituitary adenoma and remission in acromegaly patients: a retrospective cohort study. BMC Endocr Disord. Published online September 16, 2021. doi:10.1186/s12902-021-00850-2