The cause of the most of the lymphoma is unidentified. However, a number of factors can influence the risk of developing lymphoma.
DNA mutations can cause cancer by encouraging division of cells and/or reducing tumor suppressor mechanisms. Lymphoma is seldom caused by innate mutations in the DNA sequence and there is no possibility of lymphoma in children of lymphoma patients.
The incidence of lymphoma peaks in individuals over 70 years of age. Non-Hodgkin lymphoma is rarely observed in children and most commonly develops in older adults.The age groups most frequently affected by Hodgkin's lymphoma are early adults (age 15-40) and late adults (above 55).
Individuals with autoimmune diseases tend to develop lymphoma in some cases. For instance, Diabetes type 1 and Rheumatoid Arthritis. Infection with certain viruses and bacteria may increase the risk for lymphoma. These include:
Human immunodeficiency virus (HIV): This virus is the causative agent of AIDS.
Epstein-Barr virus (EBV): Infection with EBV is associated with increased risk of lymphoma. In certain geographic regions, including Africa, infection with EBV is associated with Burkitt's lymphoma.
Hepatitis C virus (HCV): The role of HCV in lymphoma risk is unclear.
The lesion is usually extraconal but can extend intraconally as well. Lacrimal gland disease may involve both orbital lobes and palpebral lobes. The lacrimal sac and extraocular muscles may also be involved. A streaky appearance may be seen, which represents irregular infiltration of the microfascial structure of retrobulbar fat. Calcification is rarely seen. Heterogeneous lesions with bony destruction are indicative of high-grade lymphomas. Bilateral lesions are possible and can signify systemic disease.
MRI of the orbits possesses good soft tissue definition; however, it lacks the ability to delineate bone destruction, which can be seen in high-grade lymphomas. MRI may miss conjunctival disease.
Orbital lesions are usually hypointense or isointense on T1-weighted MRI and hyper intense on T2-weighted images. Gadolinium enhancement is seen on T1-weighted images. This is indicative of high cellularity.
PET (FDG-PET) can sometimes find systemic extra nodal lymphomatous sites that are not detected with conventional imaging studies. This ability yields valuable information in patients with ocular lymphoma, which may result in important changes in staging and also in patient management. PET has been found to have a higher sensitivity than CT scan (86% vs. 72%) in detecting distant disease.
Vitreous biopsy remains the mainstay of diagnosis for primary central nervous system lymphoma with ocular involvement (PCNSLO). Vitreous aspiration biopsy is a safe technique whose advantage is that it best preserves the cytomorphology. Material is aspirated directly through a 25-gauge needle into a syringe. A mechanical vitrector provides better management of the tissue during the procedure and also allows more specimens to be obtained. However, specimens are often diluted and appear to undergo some art factitious change, since malignant lymphocytes are fragile to the effects of mechanical disruption. Material may also be lost in the tubing.
If vitreous samples do not provide diagnostic tissue in the presence of retinal lesions, retinal and chorioretinal biopsies or sub retinal aspiration may be done. Either an intraocular approach or a transscleral approach can be used.
Biopsy of the lesion is essential to confirm the diagnosis and also to help grade the lymphoma. The diffuse infiltrating nature of lymphomas may make their complete excision difficult. Also, their excellent response to irradiation obviates the need for complete excision.
The route of biopsy is chosen depending on the site of the lesion. Direct approach is possible for conjunctival and lid lesions, whereas orbitotomy is needed for lesions involving the lacrimal gland or posterior orbit. In the case of bilateral disease, only 1 orbit need undergo biopsy.
Lumbar puncture:- Is indicated to obtain cerebrospinal fluid (CSF) for cytology if the patient is believed to have CNS lymphoma. Bone marrow aspiration is used for staging systemic lymphomas. CT scans of the chest and abdomen are obtained to rule out retroperitoneal lymphoma. Bone scans may also be done.
The recommended therapy for stage IE tumors is radiotherapy, whereas disseminated disease is treated with chemotherapy.
Lymphoid tumors of the conjunctiva are mostly treated with local radiation therapy. It has been seen that some conjunctival lymphoma cases impulsively relapse after biopsy; therefore, follow-up without radiation is deemed an option for patients with mucosa-associated lymphoid tissue (MALT) lymphoma after the pathologic diagnosis by biopsy.
Only radiotherapy is highly effective in the management of primary orbital lymphoma.
At the time of diagnosis, around 50% of orbital lymphomas are restricted to the orbit. In such cases, local orbital low-dose (1500-3000 cGy) irradiation in fractionated doses is suggested. However, 4000 cGy is advised for high-grade tumors.
For massive orbital involvement, the patient may be recommended both chemotherapy and radiation simultaneously.
The secondary orbital lymphomas usually show extensive systemic involvement and typically have aggressive histologic classification as compared to primary orbital lymphomas do. Therefore, treatment of these lesions with chemotherapy or immunotherapy is necessary. In some cases, combination of systemic therapy with local radiation treatment is highly useful.
Lymphomas respond well to monoclonal antibody (mAb) therapy, and research is ongoing to determine if such therapy can replace chemotherapy. Rituximab, ibritumomab, and epratuzumab are examples of mAbs that either are already in use or are being tested for use in lymphoma treatment.
Antiangiogenic drugs, such as thalidomide, are also being researched for use in lymphoma treatment, as they are shown to slow the growth of cancer cells.