VÁLVULAS DE COMPUERTA 1. Generalidades

Although a complete ophthalmologic exam including indirect ophthalmoscopy leads to an accurate diagnosis of retinoblastoma in the great majority of patients, sometimes ancillary tests might be useful in the few equivocal cases. An ocular ultrasound (B scan) is readily available in most eye centers and can easily demonstrate the presence of a distinct mass in cases wherein there is doubt (see picture below) especially if there is an opacity in the cornea or lens occluding the view.

Fig. 5 Ultrasound photo showing a solid mass at the center.

However, by far the most useful ancillary procedure in the diagnosis of retinoblastoma is still a CT scan. One particular characteristic of retinoblastomas is that calcification is seen in more than 90% of tumors and the CT scan easily demonstrates this (see picture below). On the other hand, all other childhood eye pathologies very rarely calcify before the age of seven. Therefore, a child less than six years old with an intraocular mass showing calcifications on CT scan is almost certainly suffering from retinoblastoma.

Fig. 5 CT scan showing intraocular tumor with calcification on the left.

A deadly characteristic of retinoblastoma is its propensity to invade the optic nerve, and in the advanced stage spread directly into the brain. The CT scan is also useful in documenting this and guides the physicians in treatment planning.

VII. Management

Once a patient is diagnosed with retinoblastoma the situation must be treated as urgent. Visual loss is something to be considered but the threat to life is of utmost importance because untreated retinoblastoma is almost uniformly fatal.

The management of retinoblastoma is performed by a team primarily consisting of an ophthalmologist, a pediatrician and a radiologist. Small tumors such as that seen in Fig. 6 below may be treated conservatively.

Fig. 6 Small intraocular retinoblastoma.

These small tumors may be treated with lasers or cryotherapy depending on the size and location. Medium sized tumors may be treated with chemotherapy combined with the previously mentioned modalities.

Radiation therapy is also sometimes used, either alone or in combination, to save an eye with retinoblastoma.

Larger tumors occupying more than half of the eye and with no hope for vision are enucleated. It is imperative for enucleated eyes to undergo histopathologic examination to look for signs of extraocular spread. Tumors with extraocular extension have higher rates of metastasis and result in poorer prognosis.

Extraocular extension is an indication for chemotherapy post operatively.

Patients with large tumors involving the orbit have the worst prognosis. They are treated with chemotherapy and more extensive surgery. The newer chemotherapeutic drugs such as the platinum compounds are increasing the survival rates of these patients. Medical therapy is commonly used in combination with radiation treatment.

Retinoblastoma patients must be closely followed up for signs of recurrence or development of new tumors.

Heritable cases are especially at risk and have been reported to develop other malignancies in later life.

Genetic counseling for affected families is also necessary.

VIII. Summary

Retinoblastoma is a life threatening eye disease in children. It is important to differentiate it from other benign conditions because delay in treatment may mean not only loss of vision but, more importantly, loss of life. A high index of suspicion is needed when confronted with a child showing leukocoria or other signs and symptoms suggestive of retinoblastoma. A complete history and physical examination will usually lead to an accurate diagnosis which is necessary to start the appropriate treatment.

REFERENCES

1. Charl , Devron . Clinical Ocular Oncology, Churchill Livingsotne Inc. New York, NY, 1989.

2. Mc Lean, I.W.; Burnier, M.N.; Zimmerman, L.E., Jakobiec, F.A.Tumors of the Eye and Ocular Adnexa Armed Forces Institute of Pathology , Washington, DC, 1993.

3. Fine, B.S. and Yanoff, M.,Ocular Histology: A Text and Atlas, 2nd ed. Harper and Rowe, Hagerstown, MD, 1979.

SELF-TEST 1. The most common presentation of retinoblastoma is:

a. Blurring of vision b. Cat’s eye reflex c. Red eye d. Squint

2. A 6 month old child with bilateral leukocoria since age one month who was kept in an incubator for six weeks after delivery probably has:

a. Heritable retinoblastoma

b. Persistent Hyperplastic Primary Vitreous (PHPV) c. Retinopathy of Prematurity

d. Coats’ disease

3. A one year old child is brought to you with a smaller right eye with leukocoria initially noticed one month after birth. The most probable diagnosis is:

a. Retinoblastoma b. PHPV

c. ROP

d. Coats’ disease

4. A 3 year old child with leukocoria is presented to you. On examination the cornea is hazy and the anterior chamber is not very clear. What examination would be most helpful in definitive diagnosis of this patient?

a. CBC and peripheral blood smear b. Ultrasound

c. CT scan d. Bone scan

5. A four year old child with left sided leukocoria and exotropia is diagnosed with retinoblastoma, the most likely treatment modality is:

a. Laser treatment b. Chemotherapy c. Enucleation

d. External beam radiation.

6. The most pertinent histopathologic finding in an eye enucleated for retinoblastoma is:

a. Mass occupying the entire vitreous cavity.

b. Tumor seeding in the anterior chamber with glaucoma.

c. Choroidal involvement.

d. Invasion of the optic nerve beyond the margin of resection.

7. A six month old child underwent enucleation of the right with intraocular retinoblastoma, the other eye is normal. On discharge you would advice the parents:

a. That they should relax since the tumor was completely removed and no further follow up is needed.

b. To watch closely the enucleated side for recurrence.

c. To bring the patient back every few months to check if there are tumors developing on the remaining eye.

d. To see the pediatric oncologist for post op chemotherapy.

8. A man with bilateral retinoblastoma marries and the couple decide to have children, they should:

a. Not worry because the chance of having children with retinoblastoma is very small.

b. Bring their children to the doctor once they see leukocoria or other signs of retinoblastoma.

c. Take their children to be seen by an ophthalmologist the soonest time possible after birth.

d. Change their minds and not have any children.

Answers 1. B 2. C 3. B 4. c 5. C 6. D 7. C 8. C