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A radiologist is a medical professional who creates and interprets images, including x-rays, ultrasounds, MRIs, and CT scans. A neuroradiologist is trained to recognize abnormalities of the nervous system, including the brain findings associated with TSC.


Rapamycin is a drug originally designed for use in immune suppression in transplant patients, but is also known to inhibit cell growth. Rapamycin is being investigated for use in treating the tumors associated with tuberous sclerosis complex.

Renal Cell Carcinoma

Renal cell carcinoma is the most common type of kidney cancer in adults. This aggressive cancer grows in the lining of very small tubes, or tubules, inside the kidney.

Renal Cyst

A renal cyst is a fluid-filled mass that appears in the kidneys. Doctors recognize two types of renal cysts. The more common of the two typically remains small (2 mm to 1 cm in diameter), appears as a single cyst or in small numbers, and has little effect on kidney function. The second type, which affects 2 to 3 percent of people with TSC, is large (1 cm to 5 cm in diameter), often occurs in large numbers, and typically affects both kidneys. This condition is similar to a disorder called polycystic kidney disease.

Renal Ultrasound

See Ultrasound.

Retinal Achromic Patch

Retinal achromic patches are spots on the retina that are lighter or darker in pigment than surrounding tissue

Retinal Hamartoma

Retinal Hamartoma
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A retinal hamartoma is a benign tumor of the eye. Generally, hamartomas are collections of abnormally shaped cells that multiply excessively to form benign tumors. In the eye, hamartomas are composed of abnormal neurons.


See Cardiac Rhabdomyoma.


Rheb (Ras homologue enriched in brain) is a protein in the signaling pathway that involves the TSC proteins.


See Subependymal Giant Cell Astrocytoma.


A seizure is a sudden discharge of electrical activity in the brain that may cause a change in behavior, awareness, or sensation.


See Subependymal Nodule.

Shagreen Patch

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A shagreen patch is a firm yellowish-red or pink area of nodules slightly elevated above the surrounding skin and often described as having the texture of an orange peel. They vary in size from a few millimeters to more than 10 cm in diameter. In individuals with TSC, they are nearly always found on or around the lumbar region of the back, but can appear on other parts of the body as well.

Shave Excision

Shave excision is a surgical procedure in which the physician uses a blade to remove the top layer of skin. Shave excision is typically used to remove benign skin growths.

Social Worker

A social worker is a professional trained to counsel individuals and their families about emotional, social, and physical needs, and facilitate access to services and organizations.

Spontaneous Mutation

A spontaneous mutation is a mutation that is not inherited. Instead, the mutation occurs in the affected individual during the earliest stages of development, at or just after fertilization. Also known as a new, or sporadic, mutation.

Sporadic TSC

In sporadic TSC, neither parent carries the mutation. Instead, the mutation occurs spontaneously in the affected individual during the earliest stages of development, at or just after fertilization. Also known as a new mutation.

Subependymal Giant Cell Astrocytoma (SEGA)

Subependymal Giant Cell Astrocytoma (SEGA)
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A subependymal giant cell astrocytoma is a large subependymal nodule (SEN). They are benign and composed of undifferentiated dysfunctional cells, including balloon cells. In rare cases, SEGAs grow large enough to obstruct the flow of cerebrospinal fluid through the lateral ventricles of the brain and may cause hydrocephalus, an enlargement of the skull and pressure on the brain.

Subependymal Nodule (SEN)

Subependymal Nodule (SEN)
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A subependymal nodule is a benign growth that develops and grows along the wall (ependymal lining) of the brain's lateral ventricles, the spaces that contain cerebrospinal fluid. While only 15 percent of SENs grow larger than 1 cm in diameter, those that do become classified as SEGAs and are cause for concern.

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This content was last reviewed on March 30, 2006.