Differential diagnosis of pituitary masses at magnetic resonance imaging

The "chameleon" sellar lesions: a case report of unexpected sellar lesions

Introduction

The sellar region and its boundaries represent a challenging area, harboring a variety of tissues of different linings. Therefore, a variety of diseases can arise or involve in this area (i.e., neoplastic or not). A total of three challenging cases of "chameleon" sellar lesions treated via EEA were described, and the lesions mimicked radiological features of common sellar masses such as craniopharyngiomas and/or pituitary adenomas, and we also report a literature review of similar cases.

Methods

A retrospective analysis of three primary cases was conducted at the Università degli Studi di Napoli Federico II, Naples, Italy. Clinical information, radiological examinations, and pathology reports were illustrated.

Results

A total of three cases of so-called "chameleon" sellar lesions comprising two men and one woman were reported. Based on the intraoperative finding and pathological examination, we noticed that case 1 had suprasellar glioblastoma, case 2 had a primary neuroendocrine tumor, and case 3 had cavernous malformation.

Conclusion

Neurosurgeons should consider "unexpected" lesions of the sellar/suprasellar region in the preoperative differential diagnosis. A multidisciplinary approach with the collaboration of neurosurgeons, neuroradiologists, and pathologists plays a fundamental role. The recognition of unusual sellar lesions can help surgeons with better preoperative planning; so an endoscopic endonasal approach may represent a valid surgical technique to obtain decompression of the optic apparatus and vascular structures and finally a pathological diagnosis.

Magnetic resonance imaging of the hypothalamo-pituitary region

The diagnosis and management of mass lesions in the sellar and parasellar areas remain challenging. When approaching patients with possible sellar or hypothalamic masses, it is important not only to focus on imaging but also detect possible pituitary hormone deficits or excess, in order to establish an appropriate diagnosis and initiate treatment. The imaging modalities used to characterize hypothalamic and pituitary lesions have significantly evolved over the course of the past several years. Computed tomography (CT) and CT angiography play a major role in detecting various sellar lesions, especially in patients who have contraindications to magnetic resonance imaging (MRI) and can also yield important information for surgical planning. However, MRI has become the gold standard for the detection and characterization of hypothalamic and pituitary tumors, infections, cystic, or vascular lesions. Indeed, the imaging characteristics of hypothalamic and sellar lesions can help narrow down the differential diagnosis preoperatively. In addition, MRI can help establish the relationship of mass lesions to surrounding structures. A pituitary MRI examination should be obtained if there is concern for mass effect (including visual loss, ophthalmoplegia, headache) or if there is clinical suspicion and laboratory evidence of either hypopituitarism or pituitary hormone excess. The information obtained from MRI images also provides us with assistance in planning surgery. Using intraoperative MRI can be very helpful in assessing the adequacy of tumor resection. In addition, MRI images yield reliable data that allow for noninvasive monitoring of patients postoperatively.