Metaplastic bone in a cortical tuber of a young patient with tuberous sclerosis complex

Abstract

Cortical tubers are the most common brain lesions of the tuberous sclerosis complex (TSC).1 They vary widely in size, location, and appearance, may have a cystic or a calcified component, and are often epileptogenic.2,3 Histologically, tubers are hypomyelinated hamartomas, which are characterized by abnormal cortical lamination and are typically composed of giant or balloon cells, dysplastic neurons, and reactive astrocytes.4 We report the radiologic and pathologic findings of a resected calcified tuber identified as an epileptogenic focus. ### Case report. The patient is a 19-year-old right-handed woman with a known spontaneous TSC1 mutation. She was the product of a normal pregnancy. Seizure onset occurred at the age of 9 months and led to a diagnosis of TSC. Neuropathologic features include numerous cortical tubers and subependymal giant cell tumors (SGCT). The patient has experienced daily seizures since their onset. Multiple antiepileptic medications and other anticonvulsant treatments were tried without significant seizure control. The patient has a history of global developmental impairment. As part of the presurgical evaluation for neurosurgical intervention, an MRI showed SGCT, multiple tubers located in bilateral frontal, parietal, and occipital lobes, and a large (22 mm) T2 hypointense calcified lesion deep to the left superior frontal sulcus (figure). Review of prior scans revealed that the calcified component of this …