Parasellar syndromes

Radiotherapy of Parasellar Tumours

Parasellar tumours represent a wide group of intracranial lesions, both benign and malignant. They may arise from several structures located within the parasellar area or they may infiltrate or metastasize this region. The treatment of the tumours located in these areas is challenging because of their complex anatomical location and their heterogenous histology. It often requires a multimodal approach, including surgery, radiation therapy (RT), and medical therapy. Due to the proximity of critical structures and the risks of side effects related to the procedure, a successful surgical resection is often not achievable. Thus, RT plays a crucial role in the treatment of several parasellar tumours. Conventional fractionated RT and modern radiation techniques, like stereotactic radiosurgery and proton beam RT, have become a standard management option, in particular for cases with residual or recurrent tumours after surgery and for those cases where surgery is contraindicated. This review examines the role of RT in parasellar tumours analysing several techniques, outcomes and side effects.

Sellar and Parasellar Imaging

The skull base is a complex anatomical region that harbors many important neurovascular structures in a relatively confined space. The pathology that can develop at this site is varied, and many disease processes may present with similar clinical and neuroimaging findings. While computed tomography maintains a role in the evaluation of many entities and can, for instance, delineate osseous erosion with great detail and characterize calcified tumor matrices, magnetic resonance imaging (MRI) is the mainstay in the neuroimaging assessment of most pathology occurring at the skull base. Various MRI sequences have proven to be robust tools for tissue characterization and can provide information on the presence of lipids, paramagnetic and diamagnetic elements, and tumor cellularity, among others. In addition, currently available MRI techniques are able to generate high spatial resolution images that allow visualization of cranial nerves and their involvement by adjacent pathology. The information obtained from such examinations may aid in the distinction of these disease processes and in the accurate delineation of their extent prior to biopsy or treatment planning.

[Metastasis to the lateral skull base]

BACKGROUND

Tumours and metastases of the lateral skull base are rare findings. Clinically, the progressive involvement of ipsilateral cranial nerves is important.

CASE REPORT

A 69-year-old man presented with headache and palsies of the facial nerve and nerve VI. Furthermore, he had hearing loss and hypaesthesia of the trigeminal nerve (V3). Four months previously, laser therapy for carcinoma of the trachea (cT4 cN3 cM0) had been done. Computed tomography (CT) and magnetic resonance imaging (MRI) revealed an intrapetrosal mass with destruction of the lateral skull base. The findings suggested a metastasis of the tracheal carcinoma. We performed a mastoidectomy with specimen collection, and the pathological analysis revealed infiltration of a squamous cell carcinoma. The patient died within 3 weeks after radiotherapy with palliative intention despite malignant progression.

CONCLUSION

The diagnosis and therapy of metastases to the lateral skull base is an interdisciplinary challenge. CT and MRI scans are essential for planning further procedures. In cases of headache and cranial nerve palsies, a metastasis to the lateral skull base must be considered in the differential diagnosis.

An approach to the patient with painful ophthalmoplegia, with a focus on Tolosa-Hunt syndrome

The differential diagnosis of painful ophthalmoplegia is extensive and consists of numerous sinister etiologies, including neoplasms (ie, primary intracranial tumors, local or distant metastases), vascular (eg, aneurysm, carotid dissection, and carotid-cavernous fistula), inflammatory (ie, orbital pseudotumor, giant cell arteritis, sarcoidosis, and Tolosa-Hunt syndrome), and infectious etiologies (ie, fungal and mycobacterial), as well as other miscellaneous conditions (ie, ophthalmoplegic migraine and microvascular infarcts secondary to diabetes). A systematic approach to the evaluation of painful ophthalmoplegia can lead to prompt recognition of serious disorders that can be associated with significant morbidity or mortality if left untreated. Inflammatory conditions such as Tolosa-Hunt syndrome and orbital pseudotumor are highly responsive to corticosteroids but should be diagnoses of exclusion.

An uncommon presentation of orbital apex syndrome

BACKGROUND

Bilateral total ophthalmoplegia secondary to a malignancy or infection of the cavernous sinus and orbital apex is an unusual presentation. Bilateral ophthalmoplegia as the initial sign of this type of rhinocerebral pathology is also uncommon.

CASE REPORT

A 34-year old Haitian woman presented with bilateral vision loss, ptosis, total ophthalmoplegia, and ocular pain. A physical and neurologic examination, laboratory analysis, chest x-rays, and neurologic imaging studies were requested. Cranial and facial computed tomography (CT) scans showed swelling of the soft tissues proximal to the sphenoid extending into the dorsal sella and prepontine cistern, obliteration of the nasopharyngeal reflection, opacification of the ethmoid and sphenoid sinus, bony destruction of the mid-skull base, and bilateral lymphadenopathy of the neck. Magnetic resonance imaging (MRI) showed the presence of a soft tissue mass causing destruction of the skull base. Involvement of the clivus, cavernous sinuses, and sella with nasopharynx extension was observed. Hypodense centers within nasopharyngeal tissues suggested the presence of necrosis. Differential diagnosis included nasopaharyngeal carcinoma, lymphoma, or an infectious process. The patient did not consent to a biopsy and refused treatment.

CONCLUSION

This presentation is a medical emergency. A combination of surgical, medical, or radiological intervention may be required to manage rhino-cerebral diseases responsible for orbital apex syndrome. Despite advances in neurologic imaging, histologic examination of tissue obtained from a biopsy may ultimately be necessary to obtain a precise diagnosis.

Imaging the cranial nerves: Part I: methodology, infectious and inflammatory, traumatic and congenital lesions

Many disease processes manifest either primarily or secondarily by cranial nerve deficits. Neurologists, ENT surgeons, ophthalmologists and maxillo-facial surgeons are often confronted with patients with symptoms and signs of cranial nerve dysfunction. Seeking the cause of this dysfunction is a common indication for imaging. In recent decades we have witnessed an unprecedented improvement in imaging techniques, allowing direct visualization of increasingly small anatomic structures. The emergence of volumetric CT scanners, higher field MR scanners in clinical practice and higher resolution MR sequences has made a tremendous contribution to the development of cranial nerve imaging. The use of surface coils and parallel imaging allows sub-millimetric visualization of nerve branches and volumetric 3D imaging. Both with CT and MR, multiplanar and curved reconstructions can follow the entire course of a cranial nerve or branch, improving tremendously our diagnostic yield of neural pathology. This review article will focus on the contribution of current imaging techniques in the depiction of normal anatomy and on infectious and inflammatory, traumatic and congenital pathology affecting the cranial nerves. A detailed discussion of individual cranial nerves lesions is beyond the scope of this article.

Skull-base metastases

Metastasis to the skull-base particularly affects patients with carcinoma of the breast and prostate. Clinically, the key feature is progressive ipsilateral involvement of cranial nerves. Five syndromes have been described according to the metastatic site including the orbital, parasellar, middle-fossa, jugular foramen and occipital condyle syndromes. Magnetic resonance imaging (MRI) is nowadays the most useful examination to establish the diagnosis but plain films, CT scans with bone windows and isotope bone scans remain helpful to demonstrate bone erosion. Normal imaging studies do not exclude the diagnosis. The treatment depends on the nature of the underlying tumor. Radiotherapy is generally the standard treatment, while some patients with chemosensitive or hormonosensitive lesions benefit from chemotherapy or hormonotherapy and selected patients from surgical removal. Gamma Knife radiosurgery is sometimes a useful alternative, particularly for previously irradiated skull-base regions, and for small tumors (diameter < 30 mm). The overall prognosis is poor, with an overall median survival of about 2.5 years, probably because skull-base metastases appear late in the course of the disease.

Bilateral cavernous sinus syndrome in dogs: 6 cases (1999-2004)

OBJECTIVE

To determine clinical features, diagnostic imaging abnormalities, underlying disease, disease progression, and outcome in dogs with bilateral cavernous sinus syndrome.

DESIGN

Retrospective study.

ANIMALS

6 dogs.

PROCEDURE

Dogs were included if clinical signs consistent with bilateral cavernous sinus syndrome (i.e., deficits of the third, fourth, and sixth cranial nerves and at least 1 of the first 2 branches of the fifth cranial nerve) were present and a lesion of the cavernous sinus was identified by means of diagnostic imaging or postmortem examination.

RESULTS

5 dogs were evaluated because of problems referable to abnormal ocular motility or pupillomotor dysfunction, and 1 dog was evaluated because of partial motor seizures involving the face and bilateral mydriasis. Four dogs had neurologic signs referable to an extrasinusoidal lesion at the time of initial examination, and the remaining 2 dogs eventually developed extrasinusoidal signs. Besides neuroanatomic location, the only consistent neuroimaging feature was variably intense, heterogeneous enhancement of cavernous sinus lesions. Neoplasia was histologically confirmed as the underlying cause in 5 of the dogs and was suspected in the remaining dog. Median survival time for the 4 dogs that were treated was 199 days (range, 16 to 392 days).

CONCLUSIONS AND CLINICAL RELEVANCE

Results suggest that bilateral cavernous sinus syndrome is rare in dogs but should be suspected in dogs with compatible clinical signs. Affected dogs have a poor prognosis, and dogs with clinical signs of bilateral cavernous sinus syndrome should be systematically evaluated for neoplastic disease.

Painful ophthalmoplegia: Overview with a focus on tolosa-hunt syndrome

Painful ophthalmoplegia is an important presenting complaint to emergency departments, ophthalmologists, and neurologists. The etiological differential diagnosis of painful ophthalmoplegia is extensive and consists of numerous sinister etiologies including vascular (eg, aneurysm, carotid dissection, carotid-cavernous fistula), neoplasms (eg, primary intracranial tumors, local or distant metastases), inflammatory conditions (eg, orbital pseudotumor, sarcoidosis, Tolosa-Hunt syndrome), infectious etiologies (eg, fungal, mycobacterial), and other conditions (eg, microvascular infarcts secondary to diabetes, ophthalmoplegic migraine, giant cell arteritis). A systematic approach to the evaluation of painful ophthalmoplegia can lead to prompt recognition of serious disorders that if left untreated, can be associated with significant morbidity or mortality. Inflammatory conditions such as Tolosa-Hunt syndrome and orbital pseudotumor are highly responsive to corticosteroids, but should be diagnoses of exclusion.