A Compilation of Orbital and Ocular Adnexal Lymphomas on 18 F-FDG PET/CT.

The most common primary orbital cancer in adults is orbital lymphoma. Lymphomas involving the orbit, eyelid, or conjunctiva are described as ocular adnexal lymphoma (OAL). OAL comprises 2% of non-Hodgkin lymphomas but around 8% of extranodal lymphomas. OAL can appear bilaterally in any region of orbit with systemic involvement or restricted to orbit/adnexal region. When identifying systemic involvement from orbital lymphoma and other extranodal lymphomas, PET/CT has been demonstrated to have a higher sensitivity than CT. The predominant subtype of OAL is mucosa-associated lymphoid tissue (MALT)-type lymphoma, followed by follicular lymphoma.