DERMATOLOGIC MANIFESTATIONS

· Hypomelanotic macules

· Facial angiofibromas

· Reddish papules with a malar distribution.

· Ungual fibromas

CNS MANIFESTATIONS

They are the most common cause of morbidity and mortality in tuberous sclerosis.

·        Subependymal Nodules:

-          In >90% of patients.

-          Represent hamartomatous lesions lining the ventricles.

-          These lesions tend to calcify as the patient ages (Figure 3).

-          MRI:

        *Hyperintense on T1-weighted MR images and isointense to hyperintense on T2weighted and FLAIR images when they have not yet calcified.

            * Variable enhancement.

·        Cortical and Subcortical Tubers:

-          In 90% of patients.

-          Represent disorganized neurons and glial cells.

-          Location:

                        *Frontal >parietal> occipital> temporal lobe.

-          Rarely seen infratentorially.

-       Tubers typically have a triangular configuration with the apex pointing toward the ventricle.

-          MRI: (Figure 4)

                        *Hypointense on T1-weighted images and hyperintense on T2weighted and FLAIR images.

                        *The opposite pattern of signal intensity is observed in infants owing to the relative lack of myelination.

                        *Enhancement: Only 10% of tubers.

·        Cerebral White Matter Radial Migration Lines:

-          In > 80% of patients.

-         Represent  heterotopic glial and neuronal cells along the path of migration from the ventricle to the cerebral cortex.

-         Occasionally be seen extending to cortical and subcortical tubers.

-         Location: cerebral white matter of the frontal lobes bilaterally.

-         MRI: (Figure 5)

                 *Thin straight lines of T2 hyperintensity and T1 isointensity to hypointensity coursing from the periventricular white matter to the cerebral cortex .

                    *Rare enhancement.

·        Subependymal Giant Cell Astrocytomas: (Figure 6)

-          In 10–15% of patients.

-          Present later in childhood.

-         Subependymal giant cell astrocytomas are thought to arise from subependymal nodules and are slow-growing.

-     Location: Foramen of Monro. They can cause obstructive hydrocephalus.

-          MR spectroscopy:

              *Helpful in differentiating these tumors from subependymal nodules.  

        *They have a high choline-to-creatin ratio and low N-acetylaspartate–to–creatine ratio.

RENAL MANIFESTATIONS

·        Angiomyolipomas

-        In 80% of patients.

-       Represent the most common benign mesenchymal neoplasm and are composed of varying amounts of fat, smooth muscle, and blood vessels.

-        Frequently multiple and bilateral.

-        Ultrasound: (Figure 7)

                 *Small: homogeneously hyperechoic.

                 *Large: heterogeneous appearance.

            - CT: Most  consist of macroscopic fat and measure less than –20 HU (pathognomonic). (Figure 8)

-        MRI:

                        *Useful for the detection of the microscopic fat present in most angiomyolipomas.

             *These lesions can be confirmed on T1-weighted fat-suppressed MR images or chemical-shift imaging.

·        Renal Cysts Renal

-     The second most common renal manifestation of tuberous sclerosis.

-     Ussually multiple and tend to occur in younger children .

-     Usually asymptomatic unless they occur as a contiguous mutation in TSC2 and PKD1 on chromosome 16 in which case it is possible hypertension or renal failure in early adulthood.

-      Ultrasound:

                        *Multiple and anechoic at ultrasound.

                        *These cysts increase in size and number over time.

·        Renal Cell Carcinoma (RCC)

-       Incidence is similar to that in the general population, however the age at onset is much younger.

-        RCC in these patients tends to grow more slowly.

-      Tuberous sclerosis–associated RCCs are predominantly clear cell RCCs.

-          CT:

                        * Hypervascular.

                        *Heterogeneous early enhancement and early washout.

PULMONARY MANIFESTATIONS

·        Lymphangioleiomyomatosis

-      Represent the proliferation of smooth muscle cells in the lymphatics with cystic changes in the lung parenchyma.

-      CT: Multiple thin-walled cysts distributed diffusely and surrounded by normal lung parenchyma. (Figure 9)

CARDIAC MANIFESTATIONS

·        Rhabdomyomas

-      They are the main feature of tuberous sclerosis in fetuses and neonates.

-     Ultrasound:  Well-defined hyperechoic mass or masses on the ventricular septum (solitary or multiple).

-    MRI: Isointense to myocardium on T1-weighted images and hyperintense on T2-weighted images.

HEPATIC MANIFESTATIONS

·        Angiomyolipomas

-       The most common hepatic manifestation.

-       Ultrasound: echogenic masses.

-       CT: fat attenuation masses.

-       MRI: decreased signal intensity on T1-weighted fatsuppressed MR images.

SPLENIC MANIFESTATIONS 

·        Hamartomas

-        Exceedingly rare.

-      Ultrasound: hypervascular, homogeneously hyperechoic masses. Their increased vascularity is due to intralesional red pulp.

-       CT: Similar or lower attenuation in relation to the spleen. Larger lesions may have a low-attenuation central scar or necrosis.

-      MRI:  Typically hypointense on T1-weighted and hyperintense on T2-weighted images-

OSSEOUS MANIFESTATIONS

-     Focal sclerotic lesions: found in vertebrae, ribs, and the iliac aspect of the sacroiliac joints. (Figure 10)

-      Bone cysts: most commonly visualized in the phalanges of the hands and feet.