Differentiating pituitary metastases from pituitary neuroendocrine tumors in patients with a history of malignancy: clinical and magnetic resonance imaging features and quantitative morphometric analysis.

PURPOSE: To compare the clinical and MRI findings of pituitary metastases (PMs) and pituitary neuroendocrine tumors (PitNETs) in patients with a history of malignancy and to assess quantitative morphologic parameters in dumbbell-shaped lesions.

METHODS: Clinical and MRI data from 13 patients with PMs and 31 patients with PitNETs were retrospectively reviewed. For 27 dumbbell-shaped lesions, quantitative linear measurements were performed, and the R value was defined as the ratio of the neck diameter to the combined suprasellar and intrasellar widths. Receiver operating characteristic analysis assessed diagnostic performance.

RESULTS: Patients with PMs had a shorter symptom-to-detection interval (P = 0.003) and more commonly presented with headache (P = 0.004). Compared with the PitNET group, the PM group showed a higher contrast-enhanced T1-weighted signal intensity ratio (P = 0.035), more frequent pituitary stalk involvement (P = 0.024), less frequent preservation of the posterior pituitary bright spot (P < 0.001), and less frequent sellar enlargement (P = 0.010). In the subgroup with dumbbell-shaped lesions, the PM group had a smaller coronal suprasellar width (P = 0.004), smaller coronal and sagittal neck diameters, and lower coronal and sagittal R values (all P < 0.001). Coronal neck diameter and coronal R value yielded AUCs of 0.986 and 0.971, respectively.

CONCLUSION: In patients with a history of malignancy and a newly detected sellar lesion, a shorter symptom-to-detection interval, headache, pituitary stalk involvement, loss of the posterior pituitary bright spot, marked enhancement, and limited sellar enlargement may suggest PM. In dumbbell-shaped lesions, a smaller neck diameter and lower R value may provide supplementary quantitative information for differentiating PMs from PitNETs.