Tuberous Sclerosis

Tuberous sclerosis (TS) is characterized by benign tumor growth in multiple organs, predominantly the skin, brain, heart, kidney, and eye. Prominent extraocular features are summarized in Table 28-4, with examples shown in Figures 28-13 and 28-14. The classic Vogt triad of clinical findings is cognitive impairment, seizures, and facial angiofibromas. The facial angiofibromas are not usually present in young children, but hypomelanotic macules (“ash-leaf spots”) are.

The most frequent and characteristic ocular manifestation of TS is retinal phakoma, frequently termed astrocytic hamartoma (Fig 28-15). Pathologically, this growth arises from the innermost layer of the retina and is composed of nerve fibers and relatively undifferentiated cells that appear to be of glial origin. Phakomas are usually found near the posterior pole and involve the retina, the optic disc, or both. They vary in size from approximately half to twice the diameter of the disc. Vision is rarely affected.

Retinal phakomas have 3 distinct appearances. The first is typically found in very young children; these phakomas are relatively flat with a smooth surface, indistinct margins, and a gray-white color that makes them difficult to detect. The second is a sharply demarcated, elevated, yellow-white, calcified lesion with an irregular surface that has been compared to that of a mulberry. These lesions are more often found in older patients, on or adjacent to the optic disc. The third type is a transitional lesion that combines features of the first 2.

Table 28-4 Extraocular Features in Tuberous Sclerosis

Figure 28-13 Cutaneous lesions of tuberous sclerosis. A, Hypomelanotic macule (ash-leaf spot). B, Adenoma sebaceum of the face.

Figure 28-14 Brain lesions of tuberous sclerosis. A, Axial computed tomography image showing small periventricular calcifications. B, Axial T2-weighted MR image demonstrating tuberous malformations (arrows).

Figure 28-15 Fundus lesions of tuberous sclerosis, left eye. In addition to the large phakoma partially overlying the optic disc, a small hypopigmented lesion (arrow) appears in the temporal macula, and a barely visible second phakoma (arrowhead) partially obscures a retinal blood vessel near the edge of the photograph, directly below the disc. The lesions of tuberous sclerosis can vary considerably in their opaqueness and visibility.

Phakomas are present in 30%–50% of patients with TS. One to several phakomas may be found in a single eye, and 40% of cases are bilateral. There is no evidence that the number of lesions increases with age, but individual tumors have been documented to grow over time. Phakomas are not pathognomonic of TS; they occur occasionally in association with neurofibromatosis and in the eyes of unaffected persons. Retinal lesions are more common in individuals with mutations in the TSC2 gene. Hypopigmented lesions analogous to ash-leaf spots are occasionally seen in the iris or choroid.

Management of TS patients by the ophthalmologist includes monitoring of vision and ocular lesions. Difficult-to-control seizures respond to vigabatrin: up to 95% of patients experience significant reduction of seizures. However, patients treated with vigabatrin are at risk for ocular complications, which may be difficult or impossible to monitor in patients with TS.

• Aronow ME, Nakagawa JA, Gupta A, Traboulsi EI, Singh AD. Tuberous sclerosis complex: genotype/phenotype correlation of retinal findings. Ophthalmology. 2012;119(9):1917–1923.

Excerpted from BCSC 2020-2021 series: Section 10 - Glaucoma. For more information and to purchase the entire series, please visit https://www.aao.org/bcsc.