Serial Follow-Up MRI of Indeterminate Cystic Lesions of the Pineal Region: Experience at a Rural Tertiary Care Referral Center

The purpose of this study was to retrospectively assess the outcomes of temporal MRI follow-up of indeterminate cystic lesions of the pineal region. Cases of indeterminate pineal lesions were identified by a computerized search of radiology reports at our institution from 1998 to 2007. Twenty-six indeterminate pineal lesions, one each in 26 patients (six males and 20 females), were followed in the current study. Cases were included in the study if the radiology report detailed an incidentally noted but indeterminate or worrisome cystic lesion of the pineal region and if temporal follow-up MRI was recommended by the interpreting neuroradiologist. For a case to be included in our data set, a follow-up MRI study must have been obtained at least 6 months after the initial study. Follow-up imaging ranged from 7 months to 8 years. Lesions ranged in description and appearance from "probable benign cyst" with typical cystic imaging features to "pineal mass" with features of solid enhancement. We found that, within the limitations of the technique, there were no significant changes in the size or character of any indeterminate pineal region lesion followed at our institution over the time interval of 1998-2007. In our study, all pineal lesions found incidentally and for which follow-up imaging had been recommended were stable over time. These data suggest that neoplastic lesions of the pineal region either are too rare or grow too slowly to be identified by traditional temporal imaging follow-up. With increasing interest in optimal allocation of health care resources, our findings suggest that incidentally identified pineal region cystic lesions, both typical and atypical, can be followed clinically.