A giant calcified cortical tuber in a case of tuberous sclerosis

An eight-year-old girl was brought to the hospital with recurrent episodes of generalized tonic-clonic seizures since six months of age for that antiepileptic medications were started. There is a history of developmental delay.

On examination, the child had facial angiofibromas and one café-au-lait spot.  

On MRI, a large T2 hypointense cortical-subcortical tuber is seen in the left cerebral hemisphere with peripheral T2 hyperintense areas involving the left superior frontal gyrus, anterior and middle aspect of the cingulate gyrus, and middle frontal gyrus (Figure 1a-c). There is chunky calcification within the medial aspect of the superior frontal gyrus with volume loss and prominence of adjacent cortical sulci. The calcifications are better appreciated on a CT scan of the brain (Figure 2).

A cortical-subcortical tuber is seen in the left inferior temporal gyrus.

Few calcified sub-ependymal nodules (SEN) are seen lining the body of lateral ventricles.(Figure 2 and 3)

No Subependymal giant cell astrocytoma is seen.

Background

Tuberous sclerosis complex (TSC) is an autosomal dominant neurocutaneous syndrome. Also known as Bourneville disease, named after Désiré-Magloire Bourneville [1].

Clinical Perspective

The most common signs and symptoms of tuberous sclerosis are known as the classic Vogt’s triad consisting of facial angiofibroma, seizures, and mental retardation [2]. The most common manifestation is seizures. Other dermatological findings include Ash leaf spots, shagreen patch, and café-au-lait spots [3]. Northrup et al. described major and minor features for the diagnosis of tuberous sclerosis [4]. Apart from clinical manifestations, there are some major features for which imaging is needed.

Imaging Perspective

CNS manifestations of TSC include:

• Cortical/subcortical tubers: high T2 and low T1, with only 10% of tubers showing enhancement. They may calcify.
• Subependymal nodules: variable signal, frequently high T1 and iso to high T2 and frequently calcified.
• Subependymal giant cell astrocytoma: It often shows marked contrast enhancement, and accompanying hydrocephalus may be present.
• White matter abnormalities: T2 hyperintense radial bands are thought to be relatively specific for TS.

MRI is the most sensitive and specific in demonstrating these lesions however CT may be helpful in identifying calcifications.

Other extracerebral manifestations include renal angiomyolipomas, renal cysts, cardiac rhabdomyomas, and lymphangioleiomyomatosis (LAM).

Outcome: Treatment is symptomatic and directed by individual clinical manifestations. Life-long follow-up is needed with an MRI brain to detect recurrence or growth of SEGAs and to access the stability of cortical tubers. 

Take-Home Message / Teaching Points:

Neuroimaging advances have greatly improved the diagnosis of tuberous sclerosis and the treatment of children in which an MRI plays a significant role in identifying epileptogenic tubers and SEGAs for possible surgical resection.