Clinical and histological characteristics of giant GH producing pituitary adenomas

T Fukui; N Fukuhara; H Nishioka; N Kobayashi; N Inoshita; N Yoshida; H Suzuki; A Takeshita; Y Takeuchi; S Yamada

Introduction: Surgical treatment of giant GH cell adenomas (>4 cm in maximum diameter; GHomas) has been considered difficult. However, clinical and histological characteristics of these adenomas are still enigmatic. We retrospectively analyzed data of 17 giant GHomas experienced at Toranomon hospital to clarify their characteristics.

Methods: These 17 patients, accounting for 3.1% of 549 acromegalic patients undergoing surgery between 2006 and 2011, who consisted of 7 females and 10 males ranging from 17 to 48 years of age.

Results: Visual disturbance was found in 6 of 17 patients and serum GH and IGF1 levels were ranging from 2.6 to 427.6 ng/ml and 418 to 1390 ng/ml, respectively. Most tumors showed invasion to the cavernous sinus (11 patients showed Knosp’s Grade 4). Preoperative medication was applied in 12 patients and tumor shrinkage was found in 10 patients. TSS, TSS followed by craniotomy, and simultaneous combined transsphenoidal & transcranial approach was performed in 11, 3, and 3 patients, respectively. Total tumor removal was accomplished in ten patients (59%; endocrinological cure was in five patients). As surgical complications, anterior hormone deterioration occurred in three patients and new postoperative diabetes insipidus was in two patients. In addition, transient CSF leakage was found in one, carotid artery injury in one and transient ophthalmoplegia in four patients. Postoperative medication was used in six patients, whereas radiotherapy was administered in five patients. Histological findings were also various as follows; pure GH adenoma 11 patients, GH–PRL adenomas three, GH–TSH adenoma one, and GH–PRL–TSH adenomas two. Interestingly, Ki67 index <1% was in nine patients, suggesting lower biological tumor activity.

Conclusion: Our study confirmed that giant GHomas showed various endocrinological and histological findings. Moreover, they are generally very difficult to be treated and therefore multidisciplinary treatment including various surgical approaches is required to control giant GHomas.

Declaration of interest: The authors declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research project.

Funding: This research did not receive any specific grant from any funding agency in the public, commercial or not-for-profit sector.

Endocrine Abstracts

P1473