Lymphoma

General

Lymphoma is a type of cancer that develops in the lymphatic system. The lymphatic system is part of the body’s immune system and contains a network of nodes and vessels carrying white blood cells (lymphocytes) throughout the body. The two types of lymphoma include Hodgkin lymphoma and non-Hodgkin lymphoma. Hodgkin lymphoma is characterized by the presence of Reed-Sternberg cells while non-Hodgkin lymphoma encompasses a wider group of cancers including follicular lymphoma, marginal zone lymphoma, and Burkitt’s lymphoma.

These cancers are found almost always in adults and can occur unilaterally or bilaterally. They present with a palpable rubbery mass fixed to the orbital rim. Malignant lymphoma along with reactive lymphoid hyperplasia can cause gradual progressive, painless proptosis and lacrimal enlargement. Eyelid or bilateral orbital involvement may point to systemic disease.

Imaging

Patients with an orbital lymphoid lesion should be assessed for systemic lymphoma by an oncologist. Magnetic resonance imaging can show a well-defined, soft tissue mass within the orbit. Diffusion-weighted imaging can assist distinguishing lymphoma from other orbital lesions, as orbital lymphoma typically shows restricted diffusion.

Pathology

Lymphoma involves the proliferation of abnormal lymphocytes, which can be B cells, T cells, or natural killer cells. Morphology of these lymphoma cells can vary and include small/mature lymphocytes, large/immature blasts, and Reed-Sternberg cells (for Hodgkin lymphoma). These lymphoma cells can grow in clusters called follicles or can spread out evenly throughout the tissue.

Treatment & Course

Treatment for orbital lymphoma depends on the type and stage of the tumor along with the patient’s health. X-ray therapy for most orbital lymphoid lesions that are confined to orbit (50% of lymphomas) is a beneficial treatment option. Other therapies include chemotherapy to kill cancer cells, radiation to target/destroy cells in specific areas of the body, immunotherapy to fight lymphoma cells and targeted therapy to specifically target lymphoma cells, and stem cell transplants.

Note that approximately 25% of patients have systemic lymphoma later on with benign reactive hyperplasia. Moreover, 40% of patients get systemic involvement within five years with atypical lymphoid hyperplasia.