CONJUNCTIVAL LYMPHOMA

Signs and Symptoms

Malignant lymphoma.

Conjunctival lymphomas represent a mass lesion of the superficial ocular surface. They are classically described as "salmon-colored patches," and may present bilaterally in as many as 20% of patients. The lesions are fleshy and may grow rapidly. Often, they appear to arise from within the fornix and extend toward the cornea. Despite the characteristic appearance, conjunctival lymph-omas resemble several other benign tumors of the ocular surface, including squamous papilloma, pyogenic granuloma and lymphangiectasis. Patients with conjunctival lymphoma tend to be young to middle-aged adults. They may complain of chronic redness but rarely report ocular discomfort.

Pathophysiology

Lymphoma is best described as malignant growth of lymphoid tissue, or cancer of elements of the lymphatic system. Lymphoid tissue is present in most organs throughout the body, and is connected by channels and conduits to lymph nodes, located primarily in the neck, axillae, groin and abdomen. In the eye, lymphoma manifests as a conjunctival or orbital mass, a choroidal infiltration with secondary uveitis, or an infiltrative optic neuropathy.

A variety of nomenclature is used to describe lymphoid tumors of the conjunctiva. Some sources divide the lesions into three classifications: (1) benign reactive lymphoid hyperplasia; (2) atypical lymphoid hyperplasia; and (3) malignant lymphoma. Benign lymphoid hyperplasia contains mature follicles composed of B-cell lymphoblasts surrounded by a mantle zone of mature T cells.¹ Atypical lymphoid hyperplasia may represent an evolving lymphoma, containing "burned-out" or "abortive" follicles. Malignant lymphomas may be further subdivided into: (1) MALT, or mucosa- associated lymphoid tissue lymphoma (sometimes called a "MALToma"); and (2) non-MALT lymphoma. MALT lymphomas are portrayed as being less aggressive, while non-MALT lesions are considered highly malignant and invasive. The majority of conjunctival lymph-omas are monoclonal proliferations of B lymphocytes.² Lymph-oid tumors of the conjunctiva are associated with systemic lymphoma in about 31% of patients.³

Management

More extensive lesion.

Biopsy is crucial in any case of suspicious conjunctival lesions. The most critical element, after establishing the presence of a conjunctival lymphoma, is differentiating between the MALT and non-MALT varieties. In addition, any patient with biopsy-proven lymph-oma deserves a complete medical evaluation to determine if systemic lymphoma is present. This includes basic hematology (CBC with differential) as well as examination by a hematologist and/or oncologist. Radiographic imaging of the head, chest and abdomen are usually also obtained if systemic involvement is suspected.

Therapy for conjunctival lymphoma depends on the disposition of the tumor and whether there is disseminated lymphoma elsewhere in the body. Isolated conjunctival lymphoma (i.e., involving the conjunctiva but no other ocular or systemic structures) is most often treated with external beam irradiation. Dosage and exposure tends to be higher for more aggressive non-MALT lymphomas, though care must be taken to minimize long-term complications of ocular radiation such as xerophthalmia or cataract formation.⁴ Recent studies have shown that intralesional interferon may also be a viable form of therapy for MALT lymphomas of the conjunctiva.^5,6

Clinical Pearls

• Though conjunctival lymph-oma may be associated with systemic lymphoma, the ocular lesions have not been shown to metastasize to any significant degree. The five-year survival rate for MALT lymphomas is excellent and reported to be 93%.⁷
• Localized therapy for conjunctival lymphoma may not be required in individuals with disseminated lymphoma undergoing systemic chemotherapy.

Other reports in this section

• Limbal Dermoid
• Conjunctival Concretions (Ocular Lithiasis)
• Conjunctival Lymphoma
• Acute Allergic Conjunctivitis
• Phlyctenulosis (Phlyctenular Keratoconjunctivitis)