Original ArticleThe Likelihood of Remnant Nonfunctioning Pituitary Adenomas Shrinking Is Associated with the Lesion's Blood Supply Pattern
Introduction
Nonfunctioning pituitary adenoma (NFPA) usually is treated with endoscopic transsphenoidal surgery (eTSS), which rapidly relieves the patient's symptoms. A recent meta-analysis reported that the initial rate of remission after transsphenoidal surgery (TSS) was approximately 44% among patients with NFPA.1 Age, sex, tumor size, and tumor invasion were found to be correlated with prognosis in some studies but not in others.2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12 In contrast, tumor shrinkage after TSS for NFPA has been observed in some studies.8, 13
The incidence of tumor shrinkage has been reported to be approximately 50% among patients with NFPA, and cystic tumors, the additional resection of remnant tumors that are detected by intraoperative magnetic resonance imaging (MRI), a smaller tumor volume, and a smaller craniocaudal remnant tumor diameter were found to be associated positively with tumor shrinkage.13 In this study, we focused on the blood supplies of pituitary tumors. We attempted to determine whether the tumor blood supply pattern is correlated with tumor shrinkage in NFPA.
Section snippets
Patient Population
From January 2007 to June 2016, a total of 73 patients with NFPA underwent eTSS at Yamagata University Hospital. Of these, the 31 patients included in this retrospective study fulfilled the following criteria: undergoing a preoperative dynamic study involving high-field MRI conducted with a 3.0-T Discovery MR750w MRI scanner (GE Medical Systems, Milwaukee, Wisconsin, USA), found to have a remnant tumor after eTSS, and undergoing follow-up MRI without receiving additional treatment. Patients
Results
Among 37 residual lesions in 31 patients, tumor shrinkage was observed on follow-up MRI in 15 (40.5) lesions, as shown in Table 1. The mean ages of the patients in the shrinkage and no-shrinkage groups were 63 and 58.8, respectively, and the difference was not significant. Twenty-one (56.8%) and 16 (43.2%) of the remnant tumors were located at rostral and caudal sites, respectively. Remnant tumors in the rostral region were significantly more likely to shrink (P = 0.0002, Table 2). However, 7
Discussion
In this study, tumor shrinkage after TSS was seen in approximately 40% of remnant NFPA, which confirmed the findings of previous studies.7, 13 Early postoperative MRI can be used to discriminate between residual tumors, hematomas, and packing materials.14, 15 Berkmann et al.13 previously reported that there were 3 mechanisms that can explain the spontaneous regression of NFPA after eTSS: 1) the resorption of hemorrhagic changes within the remnant tumor; 2) intratumoral ischemia followed by
Conclusions
Evaluations of the blood supplies of NFPA with preoperative dynamic MRI and the locations of remnant NFPA could be useful for predicting postoperative tumor shrinkage.
References (20)
- et al.
Evaluation of fine feeding system and angioarchitecture of giant pituitary adenoma—implications for establishment of surgical strategy
World Neurosurg
(2016) - et al.
Clinical factors involved in the recurrence of pituitary adenomas after surgical remission: a structured review and meta-analysis
Pituitary
(2012) - et al.
The clinical and endocrine outcome to trans-sphenoidal microsurgery of nonsecreting pituitary adenomas
Cancer
(1991) - et al.
Long-term results in transsphenoidal removal of nonfunctioning pituitary adenomas
J Neurosurg
(1986) - et al.
An audit of selected patients with non-functioning pituitary adenoma treated by transsphenoidal surgery without irradiation
Clin Endocrinol (Oxf)
(1994) - et al.
The long-term significance of microscopic dural invasion in 354 patients with pituitary adenomas treated with transsphenoidal surgery
J Neurosurg
(2002) - et al.
Postoperative surveillance of clinically nonfunctioning pituitary macroadenomas: markers of tumour quiescence and regrowth
Clin Endocrinol (Oxf)
(2003) - et al.
Long-term recurrence and mortality after surgery and adjuvant radiotherapy for nonfunctional pituitary adenomas
J Neurosurg
(2008) - et al.
Treatment and follow-up of clinically nonfunctioning pituitary macroadenomas
J Clin Endocrinol Metab
(2008) - et al.
Early results of surgery in patients with nonfunctioning pituitary adenoma and analysis of the risk of tumor recurrence
J Neurosurg
(2008)
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Conflict of interest statement: The authors declare that the article content was composed in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.