Extraocular muscle involvement in MALT lymphomas.

We report 3 cases of extraocular muscle involvement by MALT (mucosa-associated lymphoid tissue) lymphoma. The first case was a 68-year-old woman who presented with mild proptosis of the left eye and diplopia caused by a lymphoma in the medial rectus. The other two cases presented with ptosis caused by a lymphoma in the most anterior aspect of the levator muscle. MALT lymphoma may involve extraocular muscles, either as a primary or secondary presentation. Although localization of orbital lymphoma in extraocular muscles is rare, this possibility should be considered in the differential diagnosis with other conditions involving extraocular musculature.