Orbital Lymphoma Masquerading as Euthyroid Orbitopathy.

Thyroid eye disease (TED), also called Graves orbitopathy (GO), is the most common diagnosis of orbital tissue inflammation. It is typically associated with the onset of hyperthyroidism, an autoimmune response to excess amounts of thyroid hormone. However, a visible and palpable lump, strictly unilateral or gross asymmetric eye involvement, non-axial (eccentric) proptosis, a lack of lid retraction or lid lag on downward gaze, or weakened muscle function (suggestive of tendon involvement) are the key features of non-TED mediated ocular involvement, as was found in the case we report here.