Endocrine Abstracts

JOINT2349

Introduction: The proportion of hormonally inactive pituitary adenomas (IPA) is about 10-20% of all cases of central nervous system tumors. Transsphenoidal adenomectomy is the primary treatment; however, complete tumor resection is not always achievable. The purpose of the study. To analyze the clinical, laboratory, and morphological characteristics of IPA patients and identify prognostic factors for surgical treatment outcomes.

Materials and methods: This retrospective dynamic study included 75 patients with IPA treated between 2016 and 2020. We analyzed medical history, hormonal profiles (cortisol, ACTH, TSH, free T4, LH, FSH, prolactin), imaging results (MRI), and histopathological and immunohistochemical findings. All patients underwent transsphenoidal adenomectomy as their primary treatment.

Results: Among the examined group of patients, the most common preoperative symptoms were headache (75.7%) and visual impairment (71.6%). Hypopituitarism of varying severity was diagnosed in 44% of cases, with the most frequent combination being secondary hypocortisolism, hypothyroidism, and hypogonadism. Secondary hyperprolactinemia was observed in 62.8% (49 patients). All tumors were macroadenomas, with a median volume of 7612.5 mm³ [4180.0; 15015.0]. Giant adenomas were found in 13 patients. Histological examination confirmed the diagnosis of pituitary adenoma in 68 out of 70 cases. The predominant histological subtypes were chromophobic (38.2%) and basophilic adenomas (35.3%). Immunohistochemical analysis (performed in 27 patients) revealed staining for one or more pituitary tropic hormones in 92% of cases, indicating secretory potential. The most common morphological subtype was "silent" gonadotropinomas (56%). Ki-67 immunoexpression was analyzed in 33 patients, with a median level of 4.4% [2%; 7%]. A Ki-67 index <3% was found in 33.3% of patients, while 66.7% had values >3%. Among 36 evaluated patients, non-radical tumor resection was observed in 18 (50%). Patients with no residual tumor had significantly higher Ki-67 levels (median: 6.3%) compared to those with residual tissue (median: 2.0%) (P = 0.038). Recurrence occurred in 8 patients with residual tumor, with a median time to recurrence of 14.5 months. Larger tumor volume before surgery was associated with a higher recurrence rate (P = 0.017, Mann-Whitney U-test).

Conclusions: Currently, no reliable markers predict IPA recurrence postoperatively. The presence of residual tumor tissue is a negative prognostic factor. We found no significant correlation between Ki-67 levels and recurrence; paradoxically, patients with residual tumor tissue had lower Ki-67 values. The role of Ki-67 in predicting IPA recurrence remains controversial and warrants further investigation.