Oculomotor nerve schwannoma located in the oculomotor cistern

BACKGROUND: OSs are extremely rare tumors, most often located in the interpeduncular cistern or the CS. We report an OS located predominantly within the oculomotor cistern, the arachnoid sac that surrounds the nerve for a short distance in the roof of the CS. We discuss a possible growth pattern for cavernous OSs. CASE DESCRIPTION: We report the case of a 34-year-old woman presenting with a right oculomotor nerve palsy. Magnetic resonance imaging revealed a mass within the borders of the roof of the CS extending forward toward the superior orbital fissure. A right pterional approach was undertaken, and the roof of the CS was opened just above the oculomotor nerve toward the superior orbital fissure. Although the part of the OS inside the oculomotor cistern was excised completely while preserving the anatomical continuity of the nerve, a subtotal removal was performed for the more anterior part of the tumor toward the superior orbital fissure. At 5 months follow-up, her third nerve paresis had improved dramatically. CONCLUSIONS: Resection of cavernous OSs within the oculomotor cistern, where the third nerve is clearly separated from the adjacent neurovascular structures, is feasible with functional preservation of the nerve. The chance of occurrence of the nerve palsy may increase as the resection proceeds more anteriorly toward the superior orbital fissure.     

Oculomotor nerve repair using interposed nerve graft.

A case of interposed nerve graft repair of an oculomotor nerve damaged during surgery for a laterally growing retrosellar pituitary adenoma is reported. The patient showed partial but functionally useful recovery of nerve function and was able to resume professional work. Only a few reports of end-to-end repair have been published, and they indicate that partial return of nerve function can be expected in such cases.     

Sciatic nerve schwannoma

Schwannomas are benign tumors of the nerve sheath, commonly seen in the vestibular nerve. Although they are common in the head and neck areas, their occurrence in extra-cranial locations is rare. We report a case of a sciatic nerve schwannoma and review the literature.     

Cervical vagus nerve schwannoma

Schwannomas arising from cervical cranial nerves rarely present as neck swelling. Ultrasonography, computerised tomography, magnetic resonance imaging and fine needle aspiration cytology are helpful in reaching a diagnosis. Surgical excision is the treatment of choice. A case of large cervical vagus nerve schwannoma occurring in a young lady is presented with its management.     

Malignant schwannoma of facial nerve

The occurrence of malignant schwannoma in children is rare. A search of English language literature did not reveal involvement of cranial nerve among children.     

Greater superficial petrosal nerve schwannoma

Summary Greater superficial petrosal nerve (GSPN) schwannoma is a very rare type of facial nerve schwannoma. Including our case, only 6 schwannomas have been reported to originate from the GSPN. Clinical features, imaging, diagnosis, differential diagnosis and treatment are discussed reviewing other cases in the pertinent literature.     

Oculomotor nerve palsy in patients with cerebral aneurysms

Twenty-six patients with oculomotor nerve palsy due to cerebral aneurysms were examined. There were six males and twenty females with a mean age of 55 years. 25 of the 26 aneurysms were located at the junction of the internal carotid and the posterior communicating artery and one was at the junction of the basilar artery and the superior cerebellar artery. Twelve patients had associated subarachnoid hemorrhage (SAH); the other 14 did not. The initial symptoms in many patients were ptosis and double vision. Twenty-one of the patients had total oculomotor nerve palsy, one had a sparing of medial rectus muscle; three patients had only ptosis and anisocoria, and one had oculomotor nerve palsy with pupillary sparing. All aneurysms, including giant aneurysms, were clipped under a microscope, and six oculomotor nerves were found to be decompressed at surgery. The follow-up periods were from six months to three years. Nine patients had a complete recovery of oculomotor function; thirteen had an incomplete recovery; and four remained unchanged. The mean interval between the onset of palsy and the time of surgery was 24 days in complete recovery cases, 42 days in incomplete recovery cases, and 119 days in unchanged cases. The recovery of oculomotor function started with the levator palpebrae muscle and followed by the medial rectus muscle. The recovery of pupillary function was, however, not consistent. Of the factors influencing recovery from oculomotor nerve palsy, the interval between the onset of palsy and the time of surgery was most important. Therefore, aneurysms with oculomotor nerve palsy should be operated on as early as possible, regardless of the presence or absence of SAH.     

Plexiform schwannoma of the ulnar nerve

Plexiform schwannoma is a rare benign neurogenic tumour; we report a case that arose in the ulnar nerve of a 59-year-old woman. Exploration showed a continuous multinodular tumour that involved the ulnar nerve from the hand to the upper arm; the length of the tumour was 35 cm.     

Intraspinal schwannoma of the accessory nerve

The second example of a schwannoma originating from the cervical portion of the accessory nerve is reported. The tumour was diagnosed by MRI and confirmed by surgery. The tumour was small and was located entirely within the cervical subarachnoid space without causing any detectable neurological deficit.     

Malignant schwannoma of the trigeminal nerve

Malignant schwannomas are rare in the head and neck, even though benign schwannomas of this area are common. A case of a malignant schwannoma of the fifth cranial nerve with symptoms of otalgia and serous otitis media is described. About 20 such cases have been reported in the literature.     

Intraorbital schwannoma arising from the supraorbital nerve

A 67-year-old man presented a three-month history of double vision and slight numbness at his right forehead. Neurological examination on admission demonstrated diplopia at lower gaze and mild hypesthesia at right frontal. MRI disclosed an extraconal cystic mass, centered over the superior rectus muscle, in the superior part of the right orbit. 3D-CT scan in bone window image showed an erosion of the right orbital roof. An operation was performed by a transcranial extradural anterior orbitotomy. It was noticed that the supraorbital nerve entered the cyst wall of the tumor. The mass was dissected from the surrounding intraorbital fat and was removed completely. Pathologically, diagnosis of schwannoma was made. Postoperatively, the diplopia diminished, although numbness at the right forehead remained. Orbital schwannomas constitute 1 to 4% of all orbital tumours. Identification of the nerve of origin of the tumours is difficult. Including this present case, only 11 cases of supraorbital nerve schwannoma, and only three cases of the tumour without neurofibromatosis, have been reported.     

Malignant schwannoma in the posterior tibial nerve

Our group have studied a patient affected by a malignant schwannoma in the posterior tibial nerve. Schwannomas are uncommon neoplasms that originate from the Schwann cells of the peripheral nerves: the most common forms are benign. Malignant transformation is rarer. The therapy is surgical and the operation undertaken, if possible, should be the amputation. Alternatively, where amputation is not possible due to the specific localisation or due to patient refusal, the alternative must be the largest and most radical excision possible.     

Axillary nerve schwannoma (case report)

The schwannoma is a benign tumour that can be eradicated; it usually occurs in the peripheral nerves of the upper limb. We report an exceptional localization in the axillary nerve. The diagnosis is based on the typical MRI appearance: in addition, confirmation of the diagnosis has to be made by histological examination. The surgical treatment by resection, taking care to preserve adjacent nerve fibres. This allows recovery without any after-effects since the recurrence rate as well as the potential for malignant transformation of this type of tumour is low.     

Cystic trochlear nerve schwannoma. Case report

BACKGROUND: Twenty-six cases of pathologically verified schwannomas of the trochlear nerve have been reported in the literature. Five of them had a large cystic component and a smaller solid portion. Complex skull base approaches have been usually applied for their removal. CASE DESCRIPTION: We report on a rare case of cystic trochlear schwannoma in a 52-year-old female patient. The patient presented with double vision, facial palsy, decreased hearing, hemiparesis on the right side, and severe gait instability. Magnetic resonance imaging revealed a 2.5-cm left-sided extra-axial lesion compressing the brain stem at the lower midbrain and upper pontine level. Total resection was performed via a retrosigmoid craniotomy. After the surgery, the neurological deficit diminished considerably. At 28 months follow-up, her only complaint was mild double vision when walking down the stairs and hypesthesia in the right half of her face. CONCLUSIONS: This case represents a rare pontomesencephalic lesion removed successfully via the simple retrosigmoid route.     

Intermediate nerve schwannoma: a rare tumour

The intermediate nerve (IN), also called the nerve of Wrisberg, is a relatively small nerve with a variable anatomical course. Currently, this nerve is not addressed well in the pertinent literature. Pre-operative diagnosis of IN tumours is clinically challenging due to the lack of related symptoms. Symptoms are typically caused by the functional deterioration of neighbouring anatomical structures. In this report, we describe a patient with a schwannoma that arose at the porus acusticus of the internal auditory canal; during surgery, this proved to originate from the IN. We discuss our findings in the context of previously reported cases of IN schwannomas and analyse the vague characteristics and symptoms of this rare tumour.     

A rare case of vagus nerve schwannoma

Schwannomas of the vagus nerve are very rare and the differential diagnosis is extremely difficult. They are very often asymptomatic and imaging techniques are helpful, but fine needle biopsy is often inconclusive. Total resection is the treatment of choice.