Diagnosis

Often the first sign that something is wrong with a child’s eye(s) is a strange light or whiteness reflected in the pupil of the eye under certain lighting conditions. This whiteness has been described as similar to a cat’s eye. The whiteness comes from the white surface of the tumor itself and is medically referred to as leukocoria. In some cases one or both of the child’s eyes have begun to turn inward or outward. This crossing of the eyes is medically referred to as strabismus and can be associated with the development of retinoblastoma in young children. Only rarely is the family doctor or pediatrician the first to suspect something is wrong. Because RB is a rare disease, it is highly unlikely that a pediatrician or a family doctor will have previously encountered a patient with RB.

A medical eye specialist (ophthalmologist) usually makes the diagnosis of retinoblastoma. In the office, the child’s pupils are dilated with eye drop medication and the opthamologist examines both eyes with special equipment. This examination often gives enough information to establish the diagnosis, but
complete examination of the eye(s) in a crying infant or child is difficult. To confirm the diagnosis or to determine the extent of the tumor involvement, a special X-ray called a CT scan or a MRI may be ordered. There are no blood tests available to confirm the diagnosis. The detailed diagnosis and exact location and characteristics of the tumor(s) will be determined under anaethesia when the treatment plan is decided. Depending on the severity of the tumor(s) your child may or may not be admitted to the hospital for immediate treatment.

A biopsy of the tumor(s) is never performed for retinoblastoma. A biopsy would increase significantly the risk of metastasis, the spread of the cancer cells to other parts of the body. The eye
provides a barrier against spread outside eye. As long as no route is provided for the tumor cells to exit the eye, the risk of the cancer spreading to other parts of the body is extremely low.

In extreme cases when the tumor volume within the eye is very large, there is some risk that tumor cells could exit the eye. The two possible ways that tumor cells can spread from the inside of the eye to other parts of the body is via the optic nerve to the brain and to bone marrow via the blood. If there is even a small risk that the tumor cells could spread outside the eye, two tests are performed in the operating room while your child is asleep. The first test is a bone marrow aspirate. A small amount of bone marrow is removed from the hip and is examined in the laboratory for evidence of tumor cells. The second test is a lumbar puncture. If RB tumor cells have left the eye through the optic nerve, they may be floating in the cerebral spinal fluid (CSF) which bathes the brain and the spinal column, inside the
backbone. To test the fluid for the presence of these cells, a small amount of CSF is drawn through a narrow needle at the base of the spine. The results of the tests will be given to you as soon as they become available.