Diagnosis of MALT lymphoma by conjunctival biopsy: a case report

Most extranodular lymphatic tissue is found in the intestinal mucosa. Together with similarly structured lymphatic tissue at other locations it has been named mucosa-associated lymphatic tissue (MALT). Malignant transformation of such tissue to lymphoma is well known. Although MALT lymphoma has been described in tissue physiologically void of MALT, lymphoma manifestation in the conjunctiva is rare.

We report a case of a 47-year-old woman who was referred to our clinic for symptomatic treatment and evaluation of severe symptoms of dry eyes. She was thought to suffer from Sjögren's syndrome because of xerophthalmia and xerostomia, as well as massive bilateral swelling of the parotid gland. Ophthalmological examination revealed marked hyperplasia of the conjunctiva, of which a biopsy was taken.

Histological and immunohistochemical examination of the conjunctival biopsy, together with analysis of gene rearrangement by Southern blot, led to the diagnosis of low-grade B-cell lymphoma of the MALT.

The differential diagnosis of keratoconjunctivitis sicca presenting with conjunctival swelling of unknown origin should include lymphoma, especially since Sjögren's syndrome may be associated with malignant disorders of the lymphatic system. A biopsy of suspicious conjunctival changes can clarify a multisystem disease by providing a tissue diagnosis.