Ординатура / Офтальмология / Английские материалы / Handbook of Pediatric Retinal Disease_Wright, Spiegel, Thompson_2006

FIGURE 8-6. Multifocal CHRPE or “bear tracks.”

There may be one to three lesions per eye, but bilateral involvement occurs only in 1% to 2% of cases.18 Although growth of these lesions may occur, there is no known potential for malignant transformation.

The multifocal variant of CHRPE, similar to the solitary form, does not usually cause symptoms. Ophthalmoscopically, multifocal CHRPE lesions are usually grouped in one sector of the fundus (Fig. 8-6). Several small, variably sized lesions are arranged such that they resemble animal footprints (bear tracks). They do not typically have the lacunae or halos of depigmentation that are noted in the solitary form of CHRPE. Occasionally lesions may be amelanotic and are sometimes referred to as polar bear tracks.

CHRPE AND INHERITED GASTROINTESTINAL POLYPOSIS

CHRPE lesions have been associated with familial adenomatous polyposis, Gardner’s syndrome, and Turcot’s syndrome.16,24 These autosomal dominant syndromes are associated with a very high risk of developing adenocarcinoma of the colon by age 50 years. Polyps may develop in early childhood. These patients may also

FIGURE 8-9. Fluorescein angiogram of the lesion in Figure 34-8. Note extension of the tumor into the overlying retina with retinal vascular changes.

COMBINED HAMARTOMA OF

THE RETINAL PIGMENT

EPITHELIUM AND RETINA

The clinical entity of a combined hamartoma of the retinal pigment epithelium and sensory retina was first clearly defined by Gass.7 These tumors are quite rare. Clinically, the lesions may be found at any age including early childhood and infancy. The previous clinical history is often noncontributory, and the patient’s visual complaints are dependent on the location of the tumors.

Ophthalmoscopically, the tumors may be located in a juxtapapillary (Figs. 8-10, 8-11) or peripheral distribution. Patients with juxtapapillary tumors are more commonly seen in young adulthood because of decreased or distorted vision. The tumors tend to be poorly-defined, elevated, variably pigmented, and involve part of the optic nerve and the adjacent retina. Tortuosity of the large retinal vessels emanating from the optic nerve head, a prominent feature, may be worsened by contraction of the fibroglial tissue. Additionally, the tumors may have a

prominent capillary network that can lead to macular exudation. Retinoschisis, intraretinal and subretinal lipid deposition, and retinal hole formation have been described.20 Rarely, retinal hemorrhage, vitreous hemorrhage, or choroidal neovascular membranes occur. When located peripherally, dragging of the retinal vessels is a prominent feature. Regardless of location, the tumors have a variable composition of glial tissue and RPE.

The visual prognosis is dependent on the location of the tumor. Most peripheral lesions are asymptomatic and tend to be associated with good vision. Visual acuity in juxtapapillary lesions is dependent on the extent of macular distortion or optic nerve involvement. Overall, approximately 40% of patients maintain vision of 20/40 or better and approximately 30% of patients have vision that is 20/200 or worse.19 Vitrectomy to relieve traction caused by epiretinal membrane formation usually does not improve vision.15

The diagnosis of combined hamartomas is based on the clinical appearance of the lesions. Fluorescein angiography may provide useful information regarding the vascular abnormalities associated with the tumor. Echography is of little value.

The pathogenesis of these lesions is not fully understood, but they may be developmental or arise secondary to inflammation. Evidence to support the notion that these are developmental tumors comes from cases in which the combined hamartomas are associated with neurofibromatosis, congenital anomalies of the optic disc, incontinentia pigmenti, X-linked retinoschisis, and facial hemangiomas.10 Histopathologically, disorganization of retinal architecture is noted. Sheets of proliferating RPE are seen along with increased numbers of blood vessels. Fibroglial tissue on the inner surface of the retina and vitreous condensations are a prominent feature in some cases.

CHOROIDAL OSTEOMA

Choroidal osteomas are benign tumors of the choroid consisting of mature bone that are usually found in a juxtapapillary or a macular location (Fig. 8-12). They are typically discovered in women in their teens and twenties. Occasionally, they may be seen in men and adults older than 30.The symptoms at the time of diagnosis are dependent on the location of the osteoma as well as the presence or absence of an associated serous or hemorrhagic detachment of the retina. The lesions may be bilateral in

FIGURE 8-12. Juxtapapillary choroidal osteoma extending into the macula. Note the pigmentary changes in the macula.

20% to 25% of cases. There is no known predilection for race. The exact incidence of choroidal osteoma is not known.

Ophthalmoscopically, a choroidal osteoma typically appears as a slightly elevated, yellow to orange subretinal lesion. At the time of diagnosis, mottling of the overlying retinal pigment epithelium is frequently present. Multicentric lesions may occur, but solitary lesions are the norm. A pathognomonic feature of choroidal osteoma is the appearance of small vascular tufts that emerge on the anterior surface of the tumor. These tufts are particularly evident with fluorescein angiography and represent feeder vessels exiting from the spaces between the cancellous bone that make up the tumor. These blood vessels do not cause exudation or hemorrhage.9 The presence of subretinal fluid or hemorrhage are signs of choroidal neovascular membrane development. Laser photocoagulation should be considered if the choroidal neovascular membrane appears to be vision threatening. Several treatment sessions may be required to eradicate the new blood vessels.

The visual prognosis of a choroidal osteoma is dependent on its location. Subfoveal lesions tend to have the worst prog-

nosis, with gradual visual loss secondary to progressive degeneration of the overlying retina or serous detachment. Most patients with juxtapapillary osteomas tend to have a better prognosis.

Diagnosis of choroidal osteomas is best made by ophthalmoscopic examination and fluorescein angiography. Echography may be useful in differentiating choroidal osteomas from similar lesions. A-scan ultrasound typically shows a sharp highintensity echo spike from the anterior surface of the tumor, along with high internal reflectivity (Fig. 8-13). A CT scan may show the characteristic appearance of a radioopaque lesion at the level of the choroid.

The exact pathogenesis of choroidal osteomas is unknown. Intraocular calcification has been noted in association with trauma, inflammation, congenital malformations, and longstanding retinal detachment, as well as abnormalities of calcium and phosphorus metabolism. Choroidal osteomas have similarly been described following a history of trauma or intraocular inflammation but most are seen in the absence of any associated ophthalmic problems. Female hormones probably play a role in the pathogenesis of choroidal osteomas given its preponderance in women. Familial occurrence of choroidal osteomas has also been reported.17

Two conditions that may be confused with typical choroidal osteomas are sclerochoroidal calcification and the nevus sebaceous of Jadassohn. Sclerochoroidal calcifications are typically seen along the superotemporal arcade and are more frequently multifocal. In older patients, they may occur in the absence of any abnormalities of calcium or phosphorus metabolism and probably represent calcification at the site of insertion of the superior oblique muscle.23 The linear nevus sebaceous syndrome (of Jadassohn) consists of midline facial skin lesions, seizures, mental retardation, and ophthalmologic abnormalities. The ophthalmic abnormalities include conjunctival lipodermoids, colobomata of the lids, iris, choroid, and disc, angiomas of the orbit, osseous choristomas of the choroid (similar to typical choroidal osteomas), and subretinal neovascularization.13