Findings:
Axial contrast enhanced CT of the orbits demonstrates
an enhancing left preseptal mass, adjacent to the lacrimal gland.
Differential Diagnosis:
The imaging characteristics are not specific, which allows
for a broad differential including lymphoma, primary salivary gland tumors,
EG, melanoma, and metastasis.
Discussion:
Lymphoma may be intra- or extraconal. The lesions usually
enhance strongly but may have some slight hypointensity on T2 due to hypercellularity.
The tumors usually mold to the globe margin and may appear nonaggressive,
or may be diffusely infiltrative simulating pseudotumor. Since lymphoma
and pseudotumor often have similar imaging characteristics, history may
be helpful to distinguish the two in some cases. NHL is by far the
most common. <1% of cases have the orbit as the primary or only site.
Bone destruction is uncommon.