Retinoblastoma is a malignant intraocular neoplasm that develops from the neuroectoderm of the retina and occurs mainly in young children. The retinoblastoma clinic is characterized by loss of central and binocular vision, pain, leukocoria, development of strabismus, exophthalmos, secondary inflammation and glaucoma. Examination in case of suspected retinoblastoma includes examination of vision, measurement of intraocular pressure, examination of the fundus, ultrasound of the eye, radiography of the orbit and paranasal sinuses, CT of the brain, lumbar puncture. Patients with retinoblastoma undergo photocoagulation, cryotherapy of the tumor; if it is impossible to preserve the organ of vision, enucleation of the affected eye followed by ocular replacement.
C69.2 Malignant neoplasm of the retina
Retinoblastoma is a malignant neoplasm of childhood that affects the retina, the vascular membrane of the eye, the orbit and often gives distant metastases. Disease accounts for 2.5-4.5% of cases of all malignant neoplasms in children under 15 years of age. In most cases, retinoblastoma develops at the age of 5 years, the peak incidence occurs at 2-3 years. In ophthalmology, a tumor occurs with the same frequency in girls and boys.
In 50-60% of cases, retinoblastomas have a genetic (congenital) origin. More than half of children with retinoblastoma are born from parents who had a similar disease in childhood. Congenital retinoblastoma is usually detected in children under the age of 30 months. In this case, retinoblastoma is usually combined with other congenital anomalies – heart defects, cleft palate (“cleft palate”), cortical infantile hyperostosis, etc. Patients with a genetic form have an increased risk of developing malignant neoplasms of other localization.
Sporadic cases are less common and occur for unknown reasons. Among the risk factors for the non-genetic form of retinoblastoma, it is customary to include the high age of parents, their employment in metallurgical industries, unfavorable environmental and alimentary factors that cause aberrations in the chromosomes of retinal and germ cells. This form of the tumor is manifested in older children and extremely rarely in adults.
Modern views on the histogenesis allow it to be attributed to tumors of neuroectodermal origin. Disease can originate from cells of any nuclear (granular) layer of the retina. Microscopic examination determines the absence of stroma, foci of necrosis and calcifications, different degrees of differentiation of tumor cells.
Retinoblastoma is characterized by rapid growth, metastasis along the optic nerve to the brain, as well as hematogenous spread to the bone marrow and tubular bones.
By origin, retinoblastomas are divided into hereditary and sporadic. Hereditary retinoblastomas usually affect both eyes at the same time. Sporadic retinoblastomas, as a rule, affect one eye and develop locally, with the formation of a single (unilateral) tumor node.
According to the degree of differentiation of tumor cells, there is a differentiated form of the tumor – retinocytoma and an undifferentiated form – retinoblastoma, which is more common and more malignant.
Retinoblastoma may have an endophytic type of growth in the direction of the center of the eyeball: in this case, the destruction of the layers of the retina and vitreous body occurs. With another variant of growth – exophytic, retinoblastoma infiltrates the retina, spreading into the subretinal space. Exophytic tumors can cause retinal detachment and accumulation of transudate in the subretinal space. In rare cases (1-2%), an infiltrative form of retinoblastoma occurs, which leads to diffuse thinning of the retina, accumulation of exudate in the anterior parts of the eye, the development of anterior adhesions and pseudohypopion.
According to the clinical classification of retinoblastoma according to the TNM system, the degrees of development of the primary tumor are distinguished:
- T1 – retinoblastoma occupies up to 25% of the fundus
- T2 – retinoblastoma spreads over an area of more than 25%, but less than 50% of the surface of the retina
- TK – retinoblastoma spreads to more than half of the retina or extends beyond it, but retains an intraocular location
- T4 – retinoblastoma goes beyond the orbit.
- N1 – there are metastases in regional (parotid, submandibular, cervical) lymph nodes.
- Ml – distant retinoblastoma metastases in the brain, bone marrow, bones, liver, etc. are determined. organs.
Symptoms of retinoblastoma
There are four consecutive stages in the clinical course of retinoblastoma.
I is the resting stage. There are no subjective symptoms in this period. Upon examination of the affected eye, leukocoria (a symptom of the “cat’s eye”) is revealed – a white pupillary reflex caused by the translucence of the tumor mass through the pupil. Early signs of retinoblastoma include loss of central and binocular vision, as a result of which strabismus may develop.
Stage II of glaucoma. It is accompanied by inflammatory phenomena in the eye – hyperemia, photophobia, lacrimation, the development of iridocyclitis and uveitis. Against the background of tumor invasion, a local pain syndrome is noted. The destruction of the trabecular apparatus by retinoblastoma leads to difficulty in the outflow of HCV, an increase in intraocular pressure and the occurrence of secondary glaucoma.
III – stage of germination. It is characterized by the development of exophthalmos of varying severity, invasion of the soft tissues of the orbit and destruction of its walls, the germination of retinoblastoma into the paranasal sinuses and subarachnoid space.
IV – stage of metastasis. It proceeds with the detection of distant disseminated foci in the bone marrow, liver, tubular bones, brain, skull bones. The spread of retinoblastoma occurs along the soft meninges, optic nerve, lymphogenic and hematogenic pathways. At this stage, the general condition of the patient suffers: intoxication, weakness, brain symptoms (nausea, vomiting, headache) develop.
Children with a family history of retinoblastoma should be under the constant supervision of an ophthalmologist. The development of retinoblastoma is usually indicated by a triad of symptoms: leukocoria, strabismus, pupil dilation with a weakening of its reaction to light. When these signs appear, a thorough ophthalmological examination of the child is carried out, including biomicroscopy, direct and reverse ophthalmoscopy, visometry, tonometry, gonioscopy, binocular vision examination, exophthalmometry, measurement of the angle of strabismus. With opacity of optical media, an important role in the detection of retinoblastoma belongs to ultrasound of the eye.
Intraocular biopsy can lead to the dissemination of malignant cells inside the eye, therefore, it is resorted to only if there are absolute indications. To assess the prevalence of this disease, orbit radiography, paranasal sinus radiography, CT and MRI of the brain, liver scintigraphy, osteoscintigraphy are used. To assess possible distant metastasis, lumbar puncture with examination of cerebrospinal fluid is resorted to; bone marrow puncture and myelogram examination.
In the process of diagnosis, retinoblastoma should be differentiated from cicatricial retinopathy, retinal dysplasia, hamartomas, soft tissue sarcomas, neuroblastoma metastases, orbital lesions in lymphoma and leukemia.
Children with retinoblastoma should be consulted by a neurologist and an otolaryngologist.
Treatment of retinoblastoma is carried out taking into account the stage of the tumor lesion. In this case, surgical intervention, radiation and drug chemotherapy, laser coagulation, cryotherapy, thermotherapy can be used. The right combination of these methods in many cases allows you to save the eye and vision. In the case of bilateral retinoblastoma, differentiated tactics are determined for each eye, depending on the degree of its lesion by the tumor.
Currently, ophthalmic surgeons and ophthalmic oncologists strive to adhere to the most conservative management. With lesions of the anterior part of the retina and a tumor diameter of up to 7 mm, cryodestruction of retinoblastoma is resorted to; with lesions of the posterior parts and tumor sizes up to 4 mm, photocoagulation is indicated. It is possible to conduct thermotherapy – a complex effect on the tumor with the help of microwave therapy, ultrasound and infrared radiation.
With a massive intraocular lesion, the development of glaucoma, loss and inability to restore vision, enucleation of the eye is resorted to, followed by ocular prosthetics. With the extraocular spread of retinoblastoma, exenteration of the orbit is indicated.
Retinoblastoma is extremely sensitive to radiation treatment. Radiation therapy for retinoblastoma can achieve good results in combination with organ-preserving and surgical methods of treatment. At the same time, both external remote and contact irradiation using applications of radioactive substances is possible. A complication of radiation therapy may be the development of post-radiation cataracts, radiation keratitis, xerosis.
Chemotherapy in the treatment is used for massive intraocular lesion, tumor invasion of the optic nerve, regional metastases. The combination of several cytostatics (vincristine, etoposide, carboplatin) is recognized as the most effective.
Prognosis and prevention
With timely diagnosis and detection of retinoblastoma at an early stage, a stable cure of the patient is possible with the help of organ–preserving methods – photocoagulation, cryotherapy, radiation therapy. With enucleation of the eye, there is also a high survival rate, but this operation is accompanied by the loss of the eye as an organ of vision and the formation of a cosmetic defect. Factors of unfavorable prognosis of retinoblastoma are tumor germination into the optic nerve, invasion of the choroidal membrane, extrascleral spread of the tumor, bilateral lesion.
To prevent retinoblastoma, medical and genetic counseling of families with hereditary cases of retinal cancer, examination of young children from risk groups is necessary.