Eye cancers in general are rare, but the appearance of non-Hodgkin’s lymphoma in the eye is particularly unusual. However, it’s still possible.

In this article, you’ll learn how common it is to develop cancers of the eye, what it means if that cancer is a non-Hodgkin’s type, and what symptoms and treatments to expect.

Non-Hodgkin’s lymphoma is a type of cancer that develops in your blood, specifically in a white blood cell called a lymphocyte. These types of white blood cells are part of your immune system and usually work to attack infections and illnesses.

When these cells are affected by lymphomas, they begin to grow abnormally, weakening your immune system and possibly forming tumors throughout your body.

The most common types of non-Hodgkin’s lymphoma are the varieties that form within lymph nodes. A diagnosis will also investigate which specific cells the lymphoma developed from.

Research has found that about 80% of non-Hodgkin’s lymphoma cases develop from B cells, 14% from T cells, and 6% from natural killer type cells.

Most forms of non-Hodgkin’s lymphoma form directly in your lymph nodes, which are scattered throughout your body as collection points for lymph fluid and other immune cells.

However, between 25% and 40% of non-Hodgkin’s lymphomas can develop outside of the lymph nodes. These are referred to as extranodal lymphomas.

It can be difficult to tell if extranodal lymphomas are the first place cancer formed — a primary site — or the location of cancer cells that migrated from their original source (metastasized).

The most common sites of primary extranodal lymphomas are the:

  • gastrointestinal system
  • upper digestive and respiratory systems
  • bones
  • spine

Less common sites include the:

  • breast
  • central nervous system
  • testis
  • lung
  • skin

Non-Hodgkin’s lymphoma that originates in the eye falls somewhere in the middle in terms of extranodal cancers, making up 8% and 10% of all non-Hodgkin’s extranodal lymphomas.

As a whole, however, it’s a very rare occurrence, accounting for less than 1% of all cases of non-Hodgkin’s lymphoma. It’s one of the rarest forms of cancer.

Despite being rare, there are two main types of non-Hodgkin’s lymphoma that develop in the eyes:

  1. Primary vitreoretinal lymphoma (PVRL): This refers to the primary central nervous system lymphoma (PCNSL) when its initial or primary manifestation is in the eyes. It can also affect the brain, and leptomeninges, without other systemic involvement.
  2. Primary intraocular lymphoma (PIOL): This accounts for less than 1% of this condition and is more challenging to diagnose and treat or manage.

When and where to expect PIOL

Intraocular lymphoma is one of several types of eye cancer. Although non-Hodgkin’s lymphoma is often diagnosed in people 17 and 59 years old and then again after 75, intraocular lymphomas are most common in older adults.

The jelly-like substance in your eye, called the vitreous humor, is the most common site for this type of cancer to form, but it can also appear in the lacrimal gland, the conjunctiva, or the exterior areas of the ey like the eyebrow and eyelids.

Inflammation is a primary symptom of lymphomas, but the exact symptoms of primary intraocular lymphoma can easily be mistaken for a number of conditions, possibly delaying diagnosis and treatment.

The most common symptoms reported with PIOL include:

  • blurred vision
  • a decrease or loss of vision
  • floaters” or other disruptions in your field of vision
  • redness
  • eye swelling
  • sensitivity to light
  • eye pain

These symptoms can be shared with almost every type of eye infection or disease, but with PIOL symptoms usually appear in both eyes.

In some cases, your PIOL may actually be a secondary cancer site, having metastasized from another site. PIOL could also spread to other areas of the body, so it’s possible to see systemic (body-wide) symptoms of non-Hodgkin’s lymphoma, too.

These symptoms may include:

  • enlarged or swollen lymph nodes
  • fever
  • chills
  • night sweats
  • weight loss
  • fatigue
  • feeling full after only eating a small amount
  • a swollen abdomen
  • chest pain or pressure
  • shortness of breath or cough
  • frequent infections
  • easy bruising or bleeding

Since the symptoms can mimic many other conditions, your doctor will begin by examining your vision and the structure of your eye. Blood tests may be performed, but case studies have found that these may appear normal even when PIOL is causing other severe symptoms.

In most cases, imaging using things like magnetic resonance imaging with contrast or even a biopsy are required to confirm a diagnosis of lymphoma in the eye.

If the cause of your symptoms is lymphoma, your healthcare team will need to perform additional testing to determine whether your eyes are a primary or secondary cancer site. They will also determine whether cancer cells are developing anywhere else in your body.

As with many other types of cancer, radiation and chemotherapy can be used to treat ocular cancers. There are different types that might be considered:

  • External beam radiation: This radiation type was the preferred treatment for PIOL in a 2020 study, which found 73% of the patients were successfully treated for PIOL.
  • CHOP chemotherapy regimen: This stands for cyclophosphamide, hydroxydaunorubicin, vincristine and prednisone. The same 2020 study found that 14% were treated by that method.
  • Rituximab: This monoclonal antibody treatment was the preferred treatment for 6% of people.
  • Combo therapy: That 2020 study found 2.2% were treated with a combination of chemotherapy and immunotherapy (CHOP and Rituximab).
  • Intrathecal chemotherapy: This process is where anticancer drugs are injected into the affected area, such as the eye.

Based on that 2020 study, less than 9% of the patients relapsed with new appearances of PIOL a year after treatment.

In most cases, external bean radiation is preferred over chemotherapy, unless there is a suspicion that the ocular lymphoma is a secondary cancer site or has already spread to other parts of the body.

The outlook for people with ocular cancers depends entirely on the stage and spread of the cancer. With PIOL, diagnosis is often delayed because of how difficult it is to distinguish lymphoma of the eye from other eye problems.

This means people with PIOL have poor outcomes, with relapse rates much higher.

With treatment, most people with primary or early stage ocular cancers do well, with less than 10% experiencing a relapse. Relapses were most common in people who had other primary or secondary cancer sites, systemic spread, or particular and aggressive genetic subtypes of lymphoma.

Eye cancers like ocular lymphoma are not very common, but they do happen and can be difficult to diagnose when they appear. Taking care of your eyes and getting regular eye examinations may help catch things like eye cancers early.

If you do develop an ocular lymphoma, your chances of recovery are generally good, but it will depend on the specific type and stage, as well as how early it’s caught and treated.