Findings:
An ill-defined homogenous soft tissue intensity lesion is seen surrounding the posterior aspect of the retro-orbital intra-conal optic nerve on the right side. The lesion displays low signal on T1, iso signal on T2, high signal on STIR and homogeneous enhancement. There is also a small area of signal abnormality in the upper outer right orbital quadrant involving the extraconal space with similar signal intensity.
The left orbit is unremarkable.
The cavernous sinuses are normal. No evidence of any intracranial mass lesion. The brain parenchyma is unremarkable.
The pituitary gland is normal.
The paranasal sinuses and mastoid air cells are clear. No bony abnormality is seen.
Conclusion:
Small enhancing lesions surrounding the posterior aspect of the retro-orbital intra-conal optic nerve on the right as the last the extraconal experiencing in the upper outer right orbital quadrant, likely in keeping with orbital lymphoma, DDX idiopathic orbital inflammatory pseudotumor. Referral to the lymphoma MDT and further surveillance is advised.