Objective:

To investigate the rate of lesions of the corpus callosum, including both unidentified bright objects (UBOs) and gliomas, in a large cohort of NF1 patients.

Background:

Neurofibromatosis type I is an autosomal dominant disorder with a multisystem presentation. Patients with NF1 are frequently found to have intracranial lesions, including areas of increased T2 signal intensity known as UBOs, as well as tumors known as gliomas. The presence of these lesions in the corpus callosum has not been studied in a large cohort.

Design/Methods:

We reviewed the medical records of 1373 patients (aged 3 months to 86 years) with NF1 followed at our institution over 2012-2021. Patients with UBOs or gliomas found on MRI in the corpus callosum were identified and recorded.

Results:

Of the 1373 patients analyzed, 34 were reported to have UBOs in the corpus callosum. This represents 6.3% of the 538 patients with any UBO. The majority of corpus callosum UBOs were in the splenium (41%), followed by the body (18%), and genu (12%). Nine patients were reported with corpus callosum gliomas, representing 5.6% of the 161 patients with any glioma. Of these, 7 (78%) were in the splenium. Over the course of follow-up imaging, 5/7 remained stable, 2/7 decreased in size and then stabilized, and 1/7 increased in size.

Conclusions:

Our study indicates a 2.5% and 0.7% prevalence of corpus callosum UBOs and gliomas, respectively. The majority of lesions are present in the splenium, and frequently remain stable over time. This adds to growing data regarding imaging findings in NF1 patients to better inform appropriate follow-up.