According to Dr. Kelly Maloney, of The Children's Hospital of Denver, in "Current Diagnosis & Treatment: Pediatrics," there are 200 to 300 cases of retinoblastoma every year. Ninety percent of the cases are diagnosed in children who are younger than 5 years old, for this is a cancer of children.
What Is It?
Retinoblastoma is the most common tumor for children located within the eye. It is estimated that 40 percent of retinoblastoma is hereditary, while 60 percent is not. As Dr. Maloney explains in "Current Diagnosis & Treatment: Pediatrics," a mutation in a gene on chromosome 13 causes this tumor. The gene, called the retinoblastoma gene, or RB1, stops tumors from developing. So, a mutation to this RB1 gene allows cells to grow without abiding by any controls. This leads to tumors. But there must be a mutation on the RB1 gene of both chromosomes for retinoblastoma to develop.
Symptoms
The child will have the retinoblastoma at birth. But it usually will not be noticed until it has grown to a certain size. By that time, the child will probably have leukocoria, where the tumor makes it seem as though the child has a white pupil. Leukocoria has the nickname of "cat's-eye pupil" because of its appearance. The symptoms may also include a painful red eye and glaucoma. Some children even have hemorrhaging or an eyeball that protrudes. And some have strabismus, or "cross eyes," and have lost the central part of their vision. David Korones, M.D., associate professor of pediatrics, oncology and neurology at the University of Rochester Medical Center, writes in "The Merck Manual for Healthcare Professionals" that 25 percent of children will have retinoblastoma in both their eyes. In such cases, the disease is hereditary. If the cancer has already spread before seeing a physician, which is rare, the symptoms can include nausea and vomiting, loss of appetite, and headache.
Diagnosis
According to Dr. Maloney, an ophthalmologist must make the diagnosis while the child is under general anesthesia. The diagnosis is made by the way the tumor looks. A retinoblastoma is creamy pink or white. A CT will confirm the diagnosis. The CT is also done to see the location of all parts of the tumor, if the tumor has affected the optic nerve, whether the retinoblastoma has grown outside of the eye and to check both eyes. The physician must check to see whether or not the tumor has metastasized, or spread, to the bone marrow and the meninges, which is the membrane that covers the brain. A bone marrow aspiration and biopsy from both sides of the body will determine if the tumor has metastasized to the bone marrow. A lumbar puncture to check the cerebrospinal fluid, or the fluid that circulates around the brain and spinal cord, will determine if the tumor has metastasized to the meninges.
References
- "Current Diagnosis & Treatment: Pediatrics"; William Hay, Jr., M.D., Myron Levin, M.D., Judith Sondheimer, M.D., Robin Deterding, M.D.; 2009
- The Merck Manual for Healthcare Professionals: Retinoblastoma
