Compared with multiple cranial nerve palsies, isolated nerve palsy is very rare in Non-Hodgkin's lymphoma. We experienced a case of isolated oculomotor nerve palsy as the first sign of recurrent diffuse large B-cell lymphoma (DLBCL).

A 45-year-old woman visited the ophthalmology clinic with a one-month history of left upper eyelid ptosis and diplopia. She had a history of DLBCL of the nasopharynx and has been in complete remission for three years after systemic chemotherapy. Ophthalmologic evaluation showed ptosis of the upper eyelid, anisocoria, but no definite limitations in ocular movement. After six weeks, aggravated ptosis, exodeviation of the left eye in the primary position, and ocular movement limitations in all directions except abduction were observed. Brain magnetic resonance angiography taken four weeks earlier demonstrated no intracranial vascular lesion, but an enhancing lesion in the cistern along the left oculomotor nerve was shown in brain magnetic resonance imaging. We diagnosed isolated oculomotor nerve palsy due to direct invasion of recurrent DLBCL. Cerebrospinal fluid analysis revealed tumor cells, and follow-up MRI showed progression of lymphoma into the cavernous sinus.

Although not common, isolated oculomotor nerve palsy can be the first sign of malignant lymphoma, even after complete remission.