Endocrine Abstracts

Purpose: Most of the acromegaly cases are due to agrowth hormone-secreting pituitary adenomas of which immunohistochemical subtype seperated as sparsely granulated adenoma (SGA) and densely granulated adenoma (DGA). SGA’s were reported to have more aggressive clinical course and therapy resistance. We investigated our patients for these aspects.

Method: Forty (F21, M19) patients with acromegaly who diagnosed and operated for pituitary adenoma at our University Hospital were included. Medical history, duration of the disease and comorbidities were assessed. Considering the current guidelines for acromegaly managements, serum growth hormone (with 75 g oral glucose tolerance test-OGTT), insulin like growth factor 1 (IGF-1) levels, computed tomography (CT) or magnetic resonance imagings (MRI) of the pituitary were performed. Immunohistochemical staining of postoperative tissue materials and subtypes of pituitary adenomas were evaluated by an experienced cytopathologist.

Results: Mean age of the patients was 48 years (range, 30 – 66). Of 40 patients, 30 had macroadenoma and 10 microadenoma. There were 25 (25/40) patients with SGA and 15 (15/40) with DGA. The remission rate after primary surgery of 40 patients was 9/40. Of 9 patients, 2 were SGA (2/25) and 7 DGA (7/15) (P = 0.001, SGA vs DGA). Complete disease remission was seen in 15 of 40 (37.5%) patients. In those who achieved endocrine remission, 9 had only transsphenoidal surgery (TSS) and the remaining 6 patients were treated with somatostatin analogues and gamma-knife radiotherapy additional to TSS. As compared with the DGA, SGA showed more cavernous sinus infiltrasion (18 vs 10, P = 0.05). Abnormal abdomen ultrasonography findings including hepatomegaly, hepatosteatosis, splenomegaly were found in all patients with SGA, but only in 6 patients with DGA. Furthermore, 4 neoplasia of the other site of body were found in the patients with SGA.

Conclusion: Immunohistochemical subtype of the pituitary adenoma seemed to have potential to affect the clinical course and therapy of acromegaly. SGA was revealed as more prone to cavernous sinus invasion, comorbidity and resistance to therapy. Carcinogenesis related with malignancy was more common in patients with SGA. Further studies are needed.