Clinicopathological Features and Outcomes in Lymphoma of Extraocular Muscles

To describe the clinicopathological features and report the outcomes of treatment in lymphoma involving the extraocular muscles (EOM), the largest reported case-series.

A retrospective case series of patients with lymphoma involving the EOM from a single tertiary referral orbital center, between March 1992 and March 2018. Patients with other histopathologic diagnoses or who did not have an EOM biopsy were excluded. The main outcome measures were histologic evaluation and clinical follow-up including tumor response, recurrence, and survival.

Twenty-five patients were included, 16 female; 9 male; median age 64.7 years (range 33.8-92.6 years). Unilateral involvement was present in 23 cases (92%). Lymphoma was found to be primary in 15 patients (60%), and any EOM could be affected by disease. Fourteen patients (56%) displayed impaired duction in the direction of the affected muscle. The commonest histologic type was extranodal marginal zone lymphoma of mucosa-associated lymphoid tissue in 16 cases (64%) followed by follicular lymphoma in 3 cases (12%), diffuse large B-cell lymphoma in 2 cases (8%), gamma delta T-cell lymphoma in 2 cases (8%), small lymphocytic lymphom and lymphoplasmacytic lymphoma in 1 case each (4%). All 4 patients with high-grade lymphomas (diffuse large B-cell or T cell lymphoma) were found to have systemic disease. Patients were treated with combinations of radiotherapy, chemotherapy, or immunotherapy, with low toxicity. Two patients developed treatment-related complications. With a median follow-up of 26 months (range 3-108 months), there was only 1 recurrence, which was successfully salvaged with Rituximab, and no deaths due to lymphoma.

Lymphoma of the EOM is a rare tumor with good response to treatment, few treatment-related complications and low risk of recurrence or mortality.A retrospective review of 25 patients with lymphoma of the extraocular muscles demonstrates excellent prognosis with a high rate of local remission (96%), 2 treatment-related complications, one recurrence, and no disease-related deaths.