Skull base tumor: Info & skull base tumor specialists

Although skull base tumors are predominantly benign, they can destroy bony structures and grow around the cranial nerves and vessels. Due to the complexity of skull base tumors, they should be treated in experienced centers. With appropriate surgical planning and perioperative monitoring, these complex procedures can be performed with an acceptable level of risk.

Here you will find further information as well as selected specialists and centers for skull base tumors.

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Brief overview:

Anatomy: The base of the skull is the bony barrier between the facial skull and the cranium. Important nerves and blood vessels pass through the base of the skull.
What is a skull base tumor? A tumor of the base of the skull that is usually benign but can damage nerves, bones and organs as it grows.
Causes: Congenital defects, accidental injuries, benign and malignant tumors, inflammation and other diseases of the base of the skull.
Symptoms: Skull base tumors often only cause symptoms once they have grown to a considerable size. Depending on the location, these include Smell and taste disorders, visual disturbances, double vision, facial pain and many more.
Treatment: Surgical removal or reduction is the best treatment option, but this is not always possible. Radiotherapy or chemotherapy may therefore also be recommended. A navigation system is often used during surgery.
Preoperative diagnostics: Before an operation, the surgeon must obtain as accurate a picture as possible of the location and spread of the tumor. This can be assessed using CT and MRI. Various cranial nerve functions are also tested and, if necessary, blood vessels are closed to minimize blood loss during the procedure.
Complications & risks of the operation: The close proximity to important cranial nerves and vessels can also exacerbate symptoms. Infarctions can occur during the operation and cerebrospinal fluid can leak out. There are also general risks such as infections, wound healing disorders and others.
Follow-up treatment: After an operation, radiation or medication is often administered.

What is the base of the skull?

The base of the skull is the lower part of the cranium. It therefore represents the boundary to the brain and the spaces that carry cerebrospinal fluid. The 12 cranial nerves and blood vessels pass through the base of the skull into the facial skull or neck.

The entire base of the skull can be divided into three large areas:

anterior skull base (frontobasal): Lies above the nose and paranasal sinuses as well as the orbit (eye socket) and covers the anterior cranial fossa inferiorly
Lateral skull base (laterobasis): Located above the ear and borders the middle base of the skull
parts that delimit the posterior cranial fossa.

Due to its proximity to the face and neck, the base of the skull also forms a boundary in the medical treatment spectrum. This is where

come together here. For this reason, interdisciplinary collaboration is often necessary to provide optimal care for affected patients.

Ansicht der Schädelbasis im menschlichen Schädel
Depiction of the base of the skull © Dessano | AdobeStock

Skull base tumors and other diseases of the skull base

Congenital defects can manifest themselves at the base of the skull. Other skull base diseases occur after accidents with fracture formation through the skull base. They can lead to an outflow of cerebrospinal fluid (cerebrospinal fluid fistula).

In addition, benign (benign) and malignant (malignant) tumors and inflammations can develop at the base of the skull. Common diseases of the base of the skull include

Meningiomas,
neurinomas,
carcinomas,
pituitary adenomas,
Aesthesioneuroblastomas,
chordomas,
chondrosarcomas and/or
cholesteatomas.

The vast majority of tumors are benign masses, e.g. meningiomas or neurinomas. Nevertheless, they can destroy the bony structures and grow around the cranial nerves and vessels. Skull base tumors often only become noticeable when they reach a considerable size.

Symptoms of skull base tumors

The symptoms experienced by patients depend on the growth pattern and location of the tumour. They therefore also depend on the proximity to the cranial nerves running through the base of the skull and to the brain stem.

Typical symptoms are (with details of the nerves involved):

Smell and taste disorders (olfactory nerve, olfactor nerve),
Visual disturbances (optic nerve, optic tract),
Double vision(occulomotor nerve, trochlear nerve and abducens nerve),
Facial pain or discomfort in the face(trigeminal nerve),
Paralysis of the facial muscles (facial nerve, facial nerve),
hearing loss,
deafness,
ringing in the ears(tinnitus)(acustic nerve, vestibular nerve),
dizziness,
gait instability,
swallowing disorders and
hoarseness.

Other symptoms such as

unsteady gait,
paralysis and
sensory disturbances

in the body can be triggered by pressure on the brain stem.

However, narrowing or obstruction of the cerebrospinal fluid pathways (ventricles), which leads to a cerebrospinal fluid circulation disorder(hydrocephalus), can also lead to

Gait disorders,
memory disorders,
bladder dysfunction(incontinence) and
signs of intracranial pressure such as headaches, nausea and vomiting and impaired consciousness.

can lead to

Large tumors that affect

the anterior lobe (frontal lobe) or
the temporal lobe (temporal lobe) of the brain

can also trigger personality changes and seizures.

Hormonal disorders are also observed when pressure is exerted on the pituitary gland.

Examinations before an operation

Before an operation to treat a skull base tumor, an examination must first be carried out. This is known as preoperative diagnostics.

The doctors need reliable information about

the size of the mass,
the exact localization of the process and
the extent within the skull base.

Various radiological procedures are used for preoperative diagnostics. Computed tomography (CT) can be used to assess the bony involvement and destruction. Magnetic resonance imaging (MRI) provides a better assessment of the soft tissue structures and possible intracranial involvement and infiltration.

Ärzte führen Gehirn-MRT durch
MRI allows the structures of the skull to be visualized very precisely © Gorodenkoff | AdobeStock

In addition, for some tumors, vascular imaging using

MR angiography or
by digital subtraction angiography

are required to prepare for surgery.

In order to keep intraoperative blood loss to a minimum, selective embolization (occlusion) can be carried out in advance in the case of severe tumour perfusion.

selective embolization (occlusion) of blood vessels supplying the tumour or
or, in rare cases, permanent vascular occlusion.

can be performed.

Furthermore, tests of cranial nerve function such as hearing, vision and balance tests are useful as part of the preoperative examinations. These can be supplemented by electrophysiological examinations (e.g. brainstem potentials, AEP).

Treatment of skull base tumors

Surgery on the skull base primarily involves the surgical removal of tumors of the anterior, middle and posterior skull base. The surgical area extends from the front of the eye socket through the paranasal sinuses to the foramen magnum.

Without treatment, there may be permanent loss of function or even damage to the vital centers in the brain stem. With slow-growing tumors, there is often no immediate time pressure. This means that targeted and detailed surgical planning is possible.

When planning the treatment of tumors at the base of the skull, interdisciplinary cooperation between

neurosurgery,
ENT,
maxillofacial surgery and
occasionally ophthalmology

makes sense.

It is not always possible to completely remove skull base tumors. For this reason, radiotherapy also plays a significant role in interdisciplinary treatment decisions and further therapy.

Surgery makes sense if other treatments such as drug therapy or radiotherapy

are less effective,
cause too many side effects or
are not possible.

A further indication is to confirm the diagnosis in the case of an unclear entity and genesis of a mass.

Procedure for skull base tumor surgery

The aim of every skull base tumor operation is to

to eliminate the cause of existing complaints and
to prevent or delay the occurrence of new symptoms.

The choice of surgical approach and surgical method depends on the nature and location of the mass. The aim of planning is to minimize the surgical approach as much as possible.

The procedures are performed microscopically and/or endoscopically. If indicated, the operation is computer-assisted, i.e. performed with the help of a navigation system. In addition, cranial nerve functions can be monitored during the operation.

Thanks to interdisciplinary cooperation and modern methods, even major operations on the base of the skull can be performed without permanent damage or with only minor impairment for the patient.

Possible complications and risks of skull base tumor surgery

The anatomical proximity to cranial nerves, vessels and/or the brain stem already explains some of the risks of surgery. If a tumor presses on or surrounds a cranial nerve, it can primarily damage it.

Surgery may lead to a deterioration or complete loss of function of the affected nerve or neighboring cranial nerves. Cranial nerve failures such as

Visual impairment or even blindness,
olfactory and taste disorders,
facial and eye muscle paralysis with double vision and
other complaints already listed under the symptoms

are among the frequent complications of skull base surgery.

As tumors at the base of the skull are often very heavily supplied with blood, bleeding and secondary bleeding can occur. Furthermore, tumors can also grow around blood vessels, resulting in vascular occlusion with infarcts as well as bleeding during dissection.

In addition, it can be difficult to reconstruct processes that exceed the hard meninges. This can result in the leakage of cerebrospinal fluid, a so-called cerebrospinal fluid fistula, which requires further surgical treatment. There are also general risks such as infections, wound healing disorders, thromboses and embolisms.

Follow-up treatment after skull base tumor surgery

Due to the often extensive tumor growth (e.g. into the cavernous sinus), complete surgical resection is not possible in some patients. Depending on the diagnosis and growth characteristics of the tumor, follow-up treatment is carried out after surgical reduction of the tumor mass.

Radiation therapy is the main treatment for tumors of the skull base. Depending on the tumor entity, this can take the form of intensity-modulated radiotherapy or heavy ion therapy. In the case of carcinomas, chemotherapy and/or radiotherapy is often used in coordination with the underlying disease.