Clinical Significance of T2-weighted Sequence Intensity on Magnetic Resonance Imaging in Non-functioning Pituitary Neuroendocrine Tumors (Nf-pitnets)

Abstract

Abstract Background. Little is known about the relationship between signal intensity patterns on T2-weighted magnetic resonance imaging (MRI) in non-functioning pituitary neuroendocrine tumors (NF-PitNETs). Aims. To evaluate the clinical, hormonal, histological features, and therapeutic responses according to the T2 signal intensity in NF-PitNETs. Patients and Methods. A retrospective and multicenter study was performed. NF-PitNETs were classified according to the T2-weighted MRI into hypointense, isointense and hyperintense adenomas. Results. A group of 166 NF-pitNET patients (93 men, 56%, mean age 58.5 ± 14.8 yr) was studied. Approximately half of the tumors (n=84, 50.6%) were hyperintense, while 34.3% (n=57) and 15.1% (n=25) were iso- and hypointense, respectively. The maximum tumor diameter of the isointense group [16 (13-25) mm] was significantly lower than that of hyperintense [23 (16.6-29.7) mm] group (p=0.003), without significant differences between iso- and hypointensive groups. Similarly, tumor volume of the isointense group [16 (13-25) mm] was significantly lower than that of hyperintense [23 (16.6-29.7) mm] group (p=0.002), without significant differences between iso- and hypointensive groups. Chiasmatic compression was less common in isointense (38.6%) tumors compared to hypointense (68%) and hyperintense (65.5%) tumors (p=0.003). Invasive adenomas (p=0.001) and the degree of cavernous sinus invasion (p<0.001) was more frequent in the hyperintense adenoma group compared to the remaining groups. 116 (69.9%) patients underwent surgery, 32 (19.3%) were followed by active surveillance and 18 (10.8%) were treated with cabergoline as first-line therapy. The percentage of patients with isointense tumors who underwent surgery was significantly lower than that of patients with non-isointense adenomas (59.6% vs 75.2%, p=0.038). Plurihormonal tumors and silent lactotroph adenomas were more frequent in the isointense tumor group, whereas silent corticotropinomas and silent somatotropinomas were more common in the non-isointense tumor group (p=0.02). No significant differences in the type of surgical response between the groups analyzed were found. Conclusion. Hyperintensity on T2-weighted MRI in NF-PitNETs is associated with larger and more invasive tumors compared to isointense adenomas. Non-isointense adenomas (hypo- and hyperintense) were more likely to undergo surgery compared to isointense adenomas. However, the degree of intensity on T2-weighted sequences of the adenoma does not seem to influence the type of therapeutic response in these tumors.