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Editor,—Ligneous conjunctivitis is a rare chronic membranous conjunctivitis with typical woody induration of the conjunctival tissue.1 2 It occurs most often bilaterally in female children and is of unknown aetiology.1-3 The disease process may involve other mucous membranes, such as the cervix and the trachea, occasionally leading to death by tracheal obstruction.4 Few patients with adult onset ligneous conjunctivitis have been seen.3 5 They generally experience a milder course and systemic involvement is less common. Autoimmune dysfunction, infection with an unidentified virus, and an inherited predisposition possibly combined with trauma have all been proposed as possible causes for the disease.3 5 6 Recent studies have found an inherited defect in the plasminogen system of affected children.7 Treatment of the condition is problematic and often unsuccessful.8 9
A 69 year old woman presented with recurrent unilateral conjunctivitis. She had dry eyes and foreign body sensation, but no visual impairment. Conjunctival injection with dense membranes and fibrosis of the lids was present (Fig 1). Peripheral corneal vascularisation was identified. Conventional histology confirmed the clinical diagnosis of ligneous conjunctivitis. Immunohistology for CD3, CD4, CD8, CD15, CD20, CD68, CD79a, vimentin, collagen type IV, and cytokeratin according to standard procedures was performed to characterise the inflammatory tissue (Table 1).
Before repeated surgical excision, conservative topical therapy with corticosteroids alone (0.1% dexamethasone five times daily) was unsuccessful. Subsequent topical treatment with the following: disodium cromoglycate 4% combined with 5000 IU/ml heparin eye drops (three times daily each), corticosteroids (0.1% dexamethasone five times daily), 2% cyclosporine A (three times daily), and antibiotics and artificial tears was to no avail. The membranes were excised three times within 8 months, followed by topical corticosteroids (0.1% dexamethasone or prednisolone, 0.5%) and heparin eye drops (5000 IU/ml) that were both slowly tapered from five times daily over 4 weeks.
The membranes recurred within a few weeks of each excision. Immunohistology showed a chronic inflammatory process characterised by plasma cells and lymphocytes. There was a relative shift towards CD 8+ cells in the CD4/8 ratio. Surprisingly, pancytokeratin, a marker for tissue of epithelial origin, was detected in the endothelium of the blood vessels invading the granulomatous tissue (Fig2).
Serologically, a severe type 1 plasminogen deficiency was detected. Analysis of the plasminogen gene revealed two single base mutations, Lys 19 → Glu and Arg 216 → His, a compound heterozygotic defect. Plasminogen activity was reduced to 18% (reference blood level 80–120%). Plasma plasminogen as detected by antibodies was less than 0.4 mg/dl (normal range 6–25 mg/dl).
This case represents primary onset of ligneous conjunctivitis in adulthood with the typical histology1 2 combined with serological findings that have previously only been seen in paediatric patients.7 Immunohistochemical investigations confirmed a chronic inflammatory process, consistent with a possible autoimmune origin, but could not determine the cause of this condition. Surprisingly, the antigen pattern of vascular endothelium in the granulation tissue involved pancytokeratin and was similar to that found in epithelioid angiosarcoma.10 This result needs further evaluation. Systemic plasminogen deficiency was found for the first time in an adult patient with ligneous conjunctivitis. The incidence of this gene defect in adult patients may be determined investigating more patients. This finding might become important for future treatment developments. Currently, the treatment of ligneous conjunctivitis in these patients remains ineffective.
Presented at the annual meeting of the Deutsche Ophthalmologische Gesellschaft Heidelberg; 96th Congress, Berlin, September, 1998