What Is Retinoblastoma?

Retinoblastoma (Rb) is a malignant tumor derived from photoreceptor precursor cells. It is common in children under 3 years of age and has a familial genetic predisposition. It can occur in one eye, both eyes in succession, or at the same time. The clinical manifestations of retinoblastoma are complicated and can be manifested as conjunctival congestion, edema, corneal edema, iris neovascularization, vitreous opacity, elevated intraocular pressure, and strabismus. The disease is prone to intracranial and distant metastases and often endangers the lives of children. Therefore, early detection, early diagnosis and early treatment are the keys to improve the cure rate and reduce mortality.

Basic Information

English name: Retinoblastoma
Visiting department: Ophthalmology
Multiple groups: Children under 3 years

Common symptoms: Conjunctival congestion, edema, corneal edema, iris neovascularization, vitreous opacity, elevated intraocular pressure, and strabismus, etc.
Contagious: no

Causes of retinoblastoma

The exact cause is unknown. 6% were autosomal dominant and 94% were sporadic. Among them, 25% are genetic mutations, the rest are somatic mutations, and some people think that they are related to viral infection factors. From the perspective of pathogenesis, the 13q14 tumor suppressor gene Rb1, the double allele is mutated and inactivated at the same time, leading to the occurrence of retinoblastoma.

Clinical manifestations of retinoblastoma

It is common in children under 3 years old, and the clinical symptoms are mostly white pupils.

Intraocular growth period

When the eye begins to grow in the eye, the outer eye is normal. Because the child is young, he cannot describe whether he has visual impairment, so it is generally not easy to detect in the early stage of the disease. When the tumor proliferates into the vitreous or near the lens, a yellow light reflection will appear in the pupil area. At this time, it is often found by parents because of dilated pupils, white pupils, or strabismus. Fundus changes: visible round or oval, clear borders, single or multiple, white or yellow nodular bulge, uneven surface, different sizes, new blood vessels or bleeding points. The tumor originated from the inner core layer, the endogenous type to the vitreous body, white turbidity of different sizes can be seen in the vitreous body; the origin of the outer nuclear layer, easy to choroid growth is called the exotype, often the retina Pore-free solid flat detachment occurred. Slit-lamp examination, there may be tumor cell colonies in the anterior chamber, the formation of false anterior chamber empyema, posterior corneal deposits, and gray-white tumor nodules on the iris surface, which can provide some clinical basis for early diagnosis.

Glaucoma

As the tumor gradually grows, the volume increases, the content of the eye increases, and the intraocular pressure rises, causing secondary glaucoma, which causes eye pain, headache, nausea, vomiting, and red eyes. The elasticity of the eyeball wall of children is large. Long-term high intraocular pressure can expand the ball wall and enlarge the eyeball, forming a special so-called "bull's eye" appearance, large cornea, corneosclera, etc., so it should be distinguished from congenital glaucoma.

3. Extraocular period

(1) The earliest tumor cells spread along the optic nerve into the skull. The invasion of the tumor tissue made the optic nerve thicker. If the bone texture of the optic nerve was damaged, the optic nerve hole expanded, but even on the X-ray film, the size of the optic nerve hole was normal. The possibility of metaball and intracranial metastases cannot be ruled out.

(2) The tumor penetrates the sclera and enters the orbit, causing the eyeball to protrude; it can also cause corneal edema or penetrate the cornea to grow outside the globe, and it can even protrude beyond the blepharoplasia and grow into a huge tumor.

4. Whole body metastasis

Metastases can occur at any stage, for example, tumors that occur near the optic nerve papillae. Even if they are small, there may be optic nerve metastases before the glaucoma phase, but generally this phase is the most obvious. Transfer route:

(1) Most enter the skull via the optic nerve or orbital fissure.

(2) Hematogenous metastasis to bone and liver or other organs in the body.

(3) Part is metastasized to nearby lymph nodes via lymphatic vessels.

Retinoblastoma examination

1. Ask a medical history

Some children have a family genetic history.

2. fundus examination

(1) Indications Once retinoblastoma is suspected, fundus examination under general anesthesia should be performed as soon as possible.

(2) Follow-up examination After each interventional treatment or intravenous chemotherapy cycle, fundus examination should be performed to evaluate the tumor risk.

(3) Examination method The pupils should be fully dilated in the first half an hour before the examination with Midolion eye water. After anesthesia is satisfied, the eyelids are separated with an eyelid opener, fundus examination is performed under Retcam, and peripheral retina is checked by pressing.

(4) Staging the retinoblastoma after the initial fundus examination, as follows:

1) GroupA (very low risk) small independent tumors away from key structures (diameter 3mm, confined to the retina,> 3mm from the macula,> 1.5mm from the optic disc, no vitreous, subretinal dissemination);

2) GroupB (low-risk) independent tumors of any size are limited to tumors in the retina (non-GroupA, no vitreous, subretinal dissemination, small limited subretinal fluid distance tumors 3mm)

3) GroupC (moderate risk) independent tumors of any size, as long as there is limited spread (arbitrary spread must be limited to small <3mm retinal tumors of any size can appear subretinal fluid)

4) GroupD (high risk) tumors are located in the eye, widely vitreous, subretinal implants and / or large, non-independent endogenous or exogenous tumors (spread more widely than GroupC, and may have small or oily vitreous spread or (Subretinal implant without vascular mass)

5) GroupE (very high risk) eyeball anatomy, functional damage (with neovascular glaucoma, massive intraocular hemorrhage, sterile orbital cellulitis, tumor in front of the vitreous, tumor contact with the lens, diffuse, eyeballs)

3 B-ultrasound

Can be divided into two types of solid and cystic patterns, the former may be early tumors, the latter represents advanced tumors.

4.CT inspection

(1) High-density mass in the eye.

(2) Calcified plaque in the mass.

(3) The optic nerve is thickened and the optic nerve hole is enlarged, indicating that the tumor has spread to the skull.

5.MRI examination

Compared with CT, there is no radiation damage, which can better observe whether the posterior optic nerve is thickened.

6. Postoperative pathological examination

Pathological examination was performed on the removed eyeball to determine the nature of the fundus tumor, the degree of differentiation of the retinoblastoma, and whether it broke through the eyeball wall and whether there was tumor cell infiltration in the optic nerve stump. Guide the next step in treatment.

7. Fluorescent fundus angiography

The early stage is the arterial phase, the tumor is fluorescent, the venous phase is enhanced, and it can penetrate into the tumor tissue. The fluorescence subsides late, which is of great value in diagnosis.

8. Anterior chamber cytology

Under fluorescence microscope observation, the tumor cells were orange-yellow, and the positive detection rate was high. It has been used as an indicator for clear diagnosis before treatment and observation of curative effect after treatment.

9. Urine test

Patients had increased excretion of vanillyl mandelic acid (VMA) and homovanillic acid (HVA) in their urine within 24 hours. Therefore, when urine VMA and HVA are positive, it is helpful to diagnose, but negative can not rule out tumor.

10. Lactate dehydrogenase (LDH) activity determination

When the LDH value in the aqueous humor is higher than that in the serum, and the ratio of the two is greater than 1.5, there may be a strong suggestion of retinoblastoma.

11. Other

Can still be used for isotopic scanning, scleral transillumination, carcinoembryonic antigen and so on. Rb is generally easy to diagnose after the third and fourth stages, but it is more difficult in the first and second stages. During this period, white reflective or yellow-white tissue can appear in the posterior pupil area of its lens, called the white pupil.

Retinoblastoma diagnosis

According to the fundus changes of retinoblastoma, the results of imaging examination. Can be diagnosed.

Differential diagnosis of retinoblastoma

Metastatic endophthalmitis

After the development of metastatic endophthalmitis to a certain stage, due to the presence of vitreous abscess, a yellow reflection in the pupil may appear, which is enough to confuse the diagnosis of retinoblastoma. Because these two diseases are more common eye diseases in young children, the identification of the two is even more necessary.

2. Differential diagnosis of retinoblastoma and Coats disease

The fundamental nature of Coats disease is bleeding from the outer retinal layer with exudative changes. Although there is limited proliferation, even bulges can be formed or lead to retinal detachment. However, the course of disease is slow and the range of lesions is wide. The gray-white exudate is distributed behind the retinal blood vessels. In addition to the exudate, bleeding spots and bright spots (cholesterol crystals) were also observed. Blood vessels, especially veins, appear dilated, twisted, curled, and have microhemangiomas. Lesions are often progressive, with new and old exudates appearing alternately. If bleeding enters the vitreous, proliferative vitreoretinopathy can form. Patients with this disease are mostly young men with monocular involvement. Ultrasound often does not change substantially.

Retinoblastoma treatment

At present, developed countries have rarely adopted treatment methods for eyeball removal. Instead, intravenous chemotherapy, ocular artery interventional chemotherapy, and local treatment (laser, transpupillary thermotherapy, cryotherapy, and radionuclide application) are applied according to tumor size, location, and scope. (Applier) and other eye-saving therapies, and strive to preserve useful vision. At present, the general practice is that when the risk of tumor metastasis is high and the tumor volume exceeds half of the eyeball, the eyeball removal should be considered when the above treatment is uncontrollable.

Retinoblastoma prognosis

Life prognosis is related to many factors, such as the size and location of the tumor, the sooner or later diagnosis and treatment, and whether the treatment is reasonable. Prognosis is also related to histological changes. Generally speaking, a good degree of differentiation is better than a low degree of differentiation; those with tumors limited to the retina are better than those who invade the choroid, optic nerve, or have extraocular diffusion. Analysis of the cause of death, 50% of patients died of extraocular metastasis of the tumor, and 50% were due to the occurrence of a second malignancy.

The visual prognosis of uninvolved eyes in monocular patients is good. After the affected eye is removed or treated, the other eye should be checked regularly. Most children have good eyesight after adulthood. The visual prognosis of binocular patients depends on the extent of the lesion and the treatment effect. For each retinoblastoma patient, after treatment, one should be formulated based on its clinical and pathological findings and Rb gene mutation characteristics (genetic or non-hereditary). Follow-up observation plan. If the tumor is small and does not invade the optic disc or near the macula fovea, good vision can be expected after treatment. If the tumor invades the optic disc or the macular fovea, even if the tumor is successfully cured, the visual prognosis is not good.

Retinoblastoma prevention

There are currently no effective preventive measures for retinoblastoma. For families with a family history of retinoblastoma, genetic testing and genetic counseling can reduce the chance of birth. And early neonatal fundus screening, early intervention, and improve prognosis.