Growth Curves of Subependymal Giant Cell Tumors in Tuberous Sclerosis Complex

BACKGROUND AND PURPOSE: Growth of subependymal giant cell tumor and subependymal nodules has not been well-characterized. The purpose of this study was to determine whether growth curves can differentiate subependymal giant cell tumors from subependymal nodules. MATERIALS AND METHODS: Brain MR imaging of patients with tuberous sclerosis complex were retrospectively reviewed from 2002 to 2018. All lesions in the region of the foramen of Monro were measured. Lesions were categorized on the basis of maximal diameter at the most recent scan: small lesions (<1 cm), indeterminate lesions (>1 cm), and resected lesions (>1 cm and surgically resected). Growth velocity and acceleration on serial imaging were analyzed, and growth rates were calculated between 0 and 20 years of age and compared among the 3 categories. RESULTS: Forty-one patients were analyzed. The average age at the earliest scan was 5.9 (SD = 5.7) years. One hundred twenty-six small, 27 indeterminate, and 10 resected lesions were measured. Subependymal giant cell tumors grew faster than indeterminate lesions between 6 and 15 years of age. Indeterminate lesions grew faster than small lesions at 0-10 years of age. Resected lesions showed increased velocity and acceleration of growth compared with indeterminate lesions and small lesions on serial imaging. CONCLUSIONS: Growth differentiates subependymal nodules and subependymal giant cell tumors within the first 20 years of life, and the use of velocity and acceleration of growth may refine the diagnostic criteria of subependymal giant cell tumors. Additionally, 6-15 years of age may be an important period to monitor subependymal giant cell tumors at the foramen of Monro because increased growth may help to identify subependymal giant cell tumors that will continue to grow and result in obstructive hydrocephalus.