Isolated Oculomotor Nerve Palsy: an unusual Presentation of Temporal Lobe Tumor.

INTRODUCTION: Temporal lobe tumors commonly present with seizures, headache, auditory and visual hallucination, memory disturbance. Isolated cranial neuropathies are rare in patients with tumors affecting temporal lobe. METHODS AND MATERIAL: The authors report a retrospective review of two cases of glioblastoma multiforme of the temporal lobe presenting with isolated oculomotor nerve palsy as their clinical feature.
RESULTS: Oculomotor nerve palsy in the temporal lobe tumor occurs primarily as result of herniation of uncus through the tentorium cerebellli. The tumors located anteromedially in the temporal lobe are usually asymptomatic and sudden medial expansion of these tumors due to intratumoral hemorrhage causes direct compression of the adjacent third nerve, which lies in the suprolateral border of the cavernous sinus, thereby producing painful oculomotor nerve palsy as the isolated clinical feature of these temporal lobe lesions.
CONCLUSIONS: The authors conclude that the differential diagnosis of painful isolated oculomotor nerve palsy should also include tumor of temporal lobe located anteromedially with intratumoral hemorrhage, in addition to the rupture of an aneurysm of posterior communicating artery.

Introduction

The temporal lobe is a common site of intracranial tumors. One of the most frequently observed tumor of the temporal lobe is Glioblastoma multiforme. Temporal lobe tumors commonly present with seizures, headache, auditory, visual hallucinations and memory disturbances. Isolated cranial neuropathies are rare in patients with tumors affecting temporal lobe. The authors report two cases of glioblastoma multiforme of temporal lobe presenting with isolated oculomotor nerve palsy. The relevant literature is briefly discussed.

Case - 1

A 60-year-old diabetic and hypertensive man presented with complaints of pain in right eye with drooping of right eyelid for 3 days. Neuro-ophthalmic examination revealed complete third nerve palsy on right side. Other neurological examination was unremarkable. Magnetic resonance imaging revealed an irregularly enhancing mass in the medial temporal lobe in the close proximity to the cavernous sinus. The mass was extending posteriorly into the uncus hippocampi and compressing the right cerebral peduncle (Figure–1). The patient underwent right temporal craniotomy and tumor excision. Peroperatively, the tumor was soft, vascular and necrotic suggestive of high grade glioma. Intra operatively, third nerve was found to be compressed by the tumor which was made free after tumor excision. Histopathology confirmed the diagnosis of glioblastoma multiforme with intratumoral bleed. The patient died on third postoperative day due to myocardial infarction.

Figure 1

Contrast MRI head axial section showing an irregularly enhancing mass in the right medial temporal lobe anteriorly in the close proximity to the cavernous sinus and oculomotor nerve (arrow).

Case - 2

A 56-year-old man presented with dull pain in left eye with drooping of left eyelid for 15 days. Neuro-ophthalmic examination revealed complete third nerve palsy on left side and rest of the neurological examination was unremarkable. Magnetic resonance imaging revealed a mass lesion in the medial temporal lobe and extending to the adjacent cavernous sinus. The mass was also extending posteriorly up to the hippocampus and also compressing the left cerebral peduncle (Figure – 2). The patient underwent left temporal craniotomy and tumor decompression. Intra operatively third nerve was found to be compressed by the tumor and was not infiltrated by the tumor. Intra-operatively the tumor was soft, highly vascular with blood clots inside the tumor. Histopathology findings were suggestive of glioblastoma multiforme with intratumoral hemorrhage. The patient received radiotherapy and chemotherapy post operatively and was doing well at 4 months follow up.

Figure 2

MRI head axial section showing a mass lesion in the left medial temporal lobe adjacent to the cavernous sinus and oculomotor nerve (arrow).

Discussion

Oculomotor nerve palsy in the temporal lobe tumor occurs primarily as result of herniation of uncus through the tentorium cerebellli. Direct compression of the third nerve by the tumor of the temporal lobe is rare.2 Our cases had third nerve palsy as the isolated presenting feature of the temporal lobe tumor. The polar tumors of the temporal lobe grow silently and are diagnosed when they have reached a considerable size. Our patients had temporal lobe tumor located in the anteromedial part of the temporal lobe. The haemorrhage and necrosis in the tumor resulted in the medial expansion of mass as seen in the MRI. This sudden medial expansion of the tumor caused direct compression of the third nerve, which lies in the suprolateral border of the cavernous sinus. Though our case-1 was diabetic but the involvement of pupil and associated ophthalmoplegia makes diabetes as the less likely cause of third nerve palsy in that case.

On reviewing the literature, similar presentation of glioblastoma multiforme of the temporal lobe had been reported by Al-Yamany et al.1 They also hypothesized the direct compression of third nerve by the tumor in the cavernous sinus as the cause of palsy in their patient who was also diabetic. Reinfenberger et al reported glioblastoma multiforme growing primarily along the proximal oculomotor nerve and the adjacent leptomeninges. Postmortem examination of the brain showed extraparenchymal tumor, which completely destroyed the third nerve and infiltrated the surrounding structures superficially.3 But in both of our cases per-operatively the subarachnoid part of the third nerve was found normal.

Tanaka et al reported a case of isolated oculomotor nerve paresis in case of temporal lobe anaplastic astrocytoma, which was extending to basal cistern and prepontine cistern with compression on brain stem. In their case, intra-operatively, the oculomotor nerve was noticed compressed by the part of tumor that was extending in the basal cistern.4

Conclusion

The authors present two cases of glioblastoma multiforme of temporal lobe with unusual clinical presentation in form of isolated third nerve palsy and suggest that in a case of painful complete third nerve palsy the compressive lesion may not always be an aneurysm of posterior communicating artery, it may be due to a tumor of temporal lobe located anteromedially.

The authors must be congratulated for highlighting an unusual presentation of temporal lobe tumors. The 3rd nerve palsy was the ONLY presenting complaints in these cases. Unfortunately, the percentages in the literature about the occurrence of occulomotor palsy in similar presentation is not available because only few case reports exists regarding this type of presentation. It might be of potential interest to the readers, especially for the Neurology and Neurosurgery residents, who infrequently may encounter these cases.