We describe a patient presenting with a red eye who was found to have conjunctival non-Hodgkin's lymphoma of the mucosa-associated lymphoid tissue (MALT) type.
- red eye
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A 79-year-old man presented with a 3-week history of a painless, red left eye. There was no discharge and minimal irritation. The vision in his left eye had deteriorated over several months secondary to cataract. His ophthalmic history included right cataract surgery one year previously. There was no relevant medical history.
On examination, right visual acuity was 6/9 and left was 6/18. He was found to have an infected left eye with an enlarged left caruncle and a fleshy ‘salmon-pink’ swelling that extended into the inferior forniceal conjunctiva (figure 1). The remainder of the ocular examination revealed a left cataract but no other abnormalities. There was no pre-auricular or submandibular lymphadenopathy and general examination confirmed localised disease. A biopsy of the inferior conjunctiva was performed.
Orbital computed tomography (CT) scans showed a soft tissue swelling anterior to the left globe. Conjunctival biopsy revealed a lymphoid infiltrate of the connective tissue and epithelium (figure 2). Immunostaining showed predominantly B cells with small numbers of T cells. This was consistent with a diagnosis of low grade non-Hodgkin's lymphoma of the MALT type (mucosa-associated lymphoid tissue). Blood tests including bone profile, serum immunoglobulins, marrow biopsy and CT scans of head, neck, chest, abdomen and pelvis confirmed that the disease was localised.
He was referred to the radiotherapists for treatment. He was reviewed in the eye clinic 3 months later and found to have new conjunctival lesions in the right eye. A second biopsy of the right inferior forniceal conjunctiva showed a focal infiltrate of B and T cells with lymphoepithelial lesions consistent with the working diagnosis.
In view of the multifocal nature of his disease chemotherapy was commenced with oral chlorambucil. After six courses his lesions improved and the conjunctival infection resolved. He remains under regular review.
In the early 1980s the term MALT was coined in order to describe a characteristic arrangement of lymphoid tissue found in certain mucosal surfaces.1 Mucosa-associated lymphoid tissue is now recognised as giving rise to a specific form of tumour with distinct features, distinguishing MALT lymphoma from other forms of primary, non-Hodgkin's, extranodal lymphoma.2 3
The commonest site of MALT in humans is the gastrointestinal tract, specifically stomach, terminal ileum and appendix.2 It has also been described in the bronchus, salivary, thyroid and thymus glands. It was described in the conjunctiva in 1980 by Knowles and Jakobiec.3 Lymphoid tumours of the conjunctiva can pose problems in diagnosis since there is considerable overlap between benign and malignant lesions. Under normal circumstances the conjunctiva contains small numbers of lymphocytes together with a few mast cells and Langerhans' cells. This conjunctival-associated lymphoid tissue is associated with the production of local immune responses.4 5
The majority of lymphoid tumours at this site are low grade B cell neoplasms.4 They are composed mainly of small lymphocytes with occasional larger blasts. Some tumours have a plasmacytoid morphology and pure plasma cell neoplasms are found rarely. High-grade B cell lymphomas are usually of the lymphoblastic type.6Conjunctival lymphoma may be limited to this site or it may be associated with systemic disease. The characteristic histological features of MALT are listed in boxFB1.7 8
Conjunctival MALT usually presents with mild symptoms of redness, irritation and photophobia.7 Examination findings are of orange-pink, salmon-pink or pale masses in the upper or lower fornices and are often bilateral. In all known cases no recurrence or dissemination after treatment has been described.7 The mainstay of treatment is local radiotherapy.10 However, chemotherapy is an alternative when radiation is inappropriate.
This case illustrates an unusual cause of unilateral red eye and highlights the importance of careful ocular examination and the value of a histological diagnosis.