Bilateral Conjunctival Small Lymphocytic Lymphoma Simulating Inflammatory Ocular Surface Disease: A Case Report

Conjunctival lymphoma classically appears as a painless salmon-pink subepithelial infiltrate, but its indolent forms can closely imitate inflammatory ocular surface disease and delay diagnosis, particularly when an uncommon subtype such as small lymphocytic lymphoma presents bilaterally and in isolation. A woman in her early fifties presented with one month of left ocular discomfort and sectoral redness, and slit-lamp examination revealed two multilobulated hyperaemic bulbar conjunctival nodules, clinically indistinguishable from nodular episcleritis. Topical corticosteroids and a topical non-steroidal anti-inflammatory drug relieved the ocular discomfort and hyperaemia, but the nodules regressed only partially and at no point resolved. This dissociation between symptomatic relief and persistence of the lesions was, in retrospect, the earliest argument against a purely inflammatory process. The initial work-up pointed toward inflammatory and granulomatous causes: elevated serum angiotensin-converting enzyme and lysozyme raised the possibility of sarcoidosis, although thoracic computed tomography, bronchoscopy and a first conjunctival biopsy performed without a lymphoma-directed panel were unrevealing, showing only reactive lymphoid hyperplasia. Approximately one year later, recurrent and now bilateral disease prompted a repeat biopsy with directed immunohistochemistry, which demonstrated a CD20-positive small B-cell infiltrate co-expressing CD5 and CD23 with negative cyclin D1 and CD10, consistent with chronic lymphocytic leukaemia/small lymphocytic lymphoma. Systemic staging with ¹⁸F-FDG PET/CT and bone marrow biopsy revealed no definite extra-conjunctival disease. After multidisciplinary review of observation, local radiotherapy and surgical excision, systemic therapy was preferred given the bilateral, recurrent and symptomatic course, and oral ibrutinib 420 mg once daily achieved complete clinical regression at three months and a sustained ocular response at two years, with indefinite haematological and ophthalmological surveillance planned.