We report the recurrence of a localized conjunctival lymphoma arising in mucosal-associated lymphoid tissue (MALToma) in the psoas muscle, 18 months after initial treatment with radiotherapy. Findings from systemic investigations demonstrated MALToma recurrences in the psoas muscle and the stomach. Ocular adnexal MALTomas typically manifest as localized tumors, which respond well to radiotherapy, but a proportion may recur in typical MALT sites. To our knowledge, this is the first report of a recurrence in the psoas muscle, and the clinical implication is that all patients with ocular adnexal lymphomas need to be followed up for an indefinite period.