Diagnostic Pitfalls in “Low-Grade Lymphoma” of the Orbit and Lacrimal Gland

AbstractAims: To investigate potential diagnostic pitfalls associated with the identification of low grade lymphoma in the orbit and lacrimal gland region.Methods: To systemically review all cases diagnosed as low grade lymphoma of orbit and lacrimal gland within a 2 year period at a specialist ophthalmic centre. To ascertain the frequency of diagnostic errors in this group of cases, in particular to look for known pitfalls associated with follicular colonisation by marginal zone lymphoma and the recently identified atypical variant of follicular lymphoma (FL). A series of 21 cases were reviewed.Results: We identified two diagnostic errors; one case of extra nodal marginal zone lymphoma (ENMZL) which showed follicular colonisation and was misinterpreted as a FL and a case of missed mantle cell lymphoma (MCL). We identified no cases of atypical FL.Conclusion: Within the orbit and lacrimal gland the term “low grade lymphoma” encompasses the following types of lymphoma: ENMZL, FL, MCL and chronic lymphocytic...