Tumors of the sellar region represent around 10-15% of all intracranial neoplasms and pituitary adenomas account for about 90% of pituitary tumors. Pituitary adenomas are typically benign tumors and are classified upon their hormonal secretion. The treatment of functioning or non-functioning pituitary adenomas, except for prolactinomas, is mainly surgical. Nowadays, the gold standard to treat these adenomas is the endoscopic endonasal transsphenoidal approach and the main endpoint is represented by the complete resection of the tumor. The patient is considered cured when a complete resection is visualized at the postoperative MRI for non-functioning adenomas and when a normalization of hormonal hypersecretion is obtained with hormonally active tumors. However, it may be difficult to evaluate whether a pituitary adenoma has been completely removed at the radiological follow-up.
In some cases, during the tumor resection, a cerebrospinal fluid (CSF) leak may be noticed. In these specific cases, a reconstruction of the skull base is necessary and the material most commonly used is autograft fat from the thigh or the abdomen. The radiological evolution of this fat during a long-term follow-up is however scarcely reported in literature. As residual tumor or tumor recurrences are assessed and located through serial MRIs, the presence of fat in the sellar region may modify the radiological interpretation of the extent of resection and recurrence, potentially leading to misdiagnoses.
Objectives
The aim of this study is to analyze the evolution during follow-up of allograft fat used to perform a skull base reconstruction in postoperative MRI interpretation, and to compare the independent analysis of the imaging from neurosurgical and neuroradiological teams.
Method
This is a monocentric retrospective observational study. The data of all the patients with a pituitary adenoma necessitating a skull base reconstruction between January 2007 and December 2018 will be collected and analyzed. Every patient with a history of previous surgery performed in another institute will not be included in the population of the study, as well as patients with no skull base reconstruction, or those whose
follow-up is less than 6 months.
Results
Results indicated that the autograft fat takes at least 4 years to shrink by 60.8% of its initial size. They also demonstrate that there is a discrepancy between neuroradiological and neurosurgical interpretations on 15.7% of the follow-up images.
Conclusion
In conclusion, we managed to measure how fast the autograft fat placed in the sella resorbs but could not determine if it disappears completely. This study also showed a misunderstanding between the medical interpretations of the MRIs. An imaging technique such as FIESTA could be interesting to test in such situations.