Background: Solitary involvement of the sphenoid sinus has rarely been reported in non-Hodgkin's lymphoma. Isolated oculomotor nerve palsy is uncommon as an initial presentation of malignant tumors of the sphenoid sinus.
Case presentation: A 53-year-old woman presented with a three-month history of headache and diplopia. Neurological examination revealed complete left oculomotor nerve palsy. Magnetic Resonance Imaging (MRI) demonstrated a homogenous soft-tissue lesion occupying the left sphenoid sinus and invading the left cavernous sinus. The patient underwent transsphenoidal biopsy and the lesion was histologically diagnosed as non-Hodgkin's lymphoma, diffuse large B-cell type. Tumor cells were positive for CD20 and negative for CD3. Following six cycles of chemotherapy, the left oculomotor nerve palsy that had been previously observed was completely resolved. There was no enhancing lesion noted on follow-up MRI.
Conclusion: It is important to recognize that non-Hodgkin's lymphoma of the sphenoid sinus can present with isolated oculomotor nerve palsy, although it is extremely rare. The cranial nerve deficits can resolve dramatically after chemotherapy.