Lymphoma refers to a cancer that originates from the lymphatic cells, that is, the white blood cells. It attacks the cells in the immune system. Primary intraocular lymphoma (PIOL) is a rare cancer that develops in the eye. PIOL belongs to the group of lymphoma called non-Hodgkin’s B cell lymphoma.
Primary vitreoretinal lymphoma may develop in the retina (a light-sensitive tissue at the back of the eye). It may also develop in the vitreous (jelly-like fluid in the eye) and in the optic nerve. The optic nerve is found at the back of the eye.
Primary uveal lymphoma affects the uvea (in the choroid layer). It is associated with the primary central nervous system lymphoma if it initially manifests in the eye.
PIOL affects more women than men. It also affects both eyes though it may occur in one eye.
- Primary vitreoretinal lymphoma - Large B cell lymphoma associated with the central nervous system)
- Primary uveal lymphoma - It’s an extra nodal marginal B cell lymphoma.
Causes and Risk Factors
Causes of PIOL remain unknown. However, it is believed that people with immune-related system problems like AIDS are more prone to PIOL. Individuals who take anti-rejection drugs following a transplant are also at risk.
Other people who may be affected include those with rheumatoid arthritis. Inheritance may play a role in increasing the likelihood of developing PIOL. People with a history of systemic lymphoma and diagnosed with chronic uveitis (inflammation of the uvea) are at risk too. Also, individuals aged 40 to 60 years are likely to develop PIOL.
Signs & Symptoms
The signs of primary uveal lymphoma include:
- An anterior or posterior uveitis
- Subretinal infiltrates (local inflammation of the retina)
- Generally, the signs for PIOL may include:
- A vitreous haze
- Cells observed in sheets or clamps
An individual may present the following symptoms for PIOL:
- Blurry vision
- Painless decreased vision
- Vitreous floaters (spots in the field of vision)
- Red eye
- Swelling in the eye
It is difficult to diagnose primary uveal lymphoma because it is rare and may erroneously present itself as uveitis. The eye professional may conduct the following tests:
- Assess the patient’s symptoms and check vision and eye movements
- Use an ophthalmoscope (instrument with a light and a magnifying glass)
- Biopsy/Cytological tissue analysis using Pars Plana vitrectomy (PPV)
- Metastatic survey (imaging of the brain, abdomen, pelvis and chest)
- Imaging (photos of the fundus or back of the eye)
- Lumbar puncture to obtain cerebrospinal fluid (CSF)
- Fundus fluorescein angiography (ultrasound of the eye)
- Optical coherence tomography (imaging that takes a cross-section of pictures)
Treatment of PIOL is directed toward shrinking the tumor or killing the cancer cells.
Treatment of PIOL is dependent on how far the tumor has spread. A team of eye doctor are involved in treating PIOL. They may include a radiation oncologist, a medical oncologist and a neuro oncologist.
Often, treatment for PIOL uses chemotherapy. Drugs such as Methotrexate and Rituximab, delivered intravenously (systemic), may be used. Other drugs are delivered intravitreally, that is, an injection through the eye. Still others are delivered intrathecally (fluid injected in the spine). Intravitreal and intrathecal modes of delivery carry the advantage of reducing potential side effects. They also enable chemotherapy to be delivered right inside the affected area.
External beam radiation therapy is an alternative option. Radiation is used to shrink tumors and kill cancer cells. It uses very high energy. The radiation may be done only in the affected eye or in both eyes. It may also target the spinal cord and the brain. Radiation helps to destroy those cells that may be hidden. It also helps prevent the cancer from spreading.
If no changes are noted, the doctor may recommend a high dose of chemotherapy. After administering chemotherapy, the doctor may do a stem cell transplant.
Radiation usually carries some complications. They include radiation retinopathy, corneal ulcer, dry eye, cataract, optic neuropathy and neovascular glaucoma. If administered on the brain, it may lead to complications such as dementia. Hence the preference to do radiology on the eye.
The multiple injections of Methotrexate and Rituximab may lead to ocular perforation.
Death is a likelihood with PIOL, even with treatment. Many patients dealing with lymphoma of the central nervous system usually succumb to the disease within two years. Lymphoma found in the brain often presents a poor prognosis.
PIOL can also lead to blindness because of the destruction of the eye structures during radiology.
Lymphomas generally are known to recur especially where only systemic chemotherapy is used. Thus, individuals should be followed up every six months for two years after completing the treatment.