Skull Base Tumors
What Is Cancer Of The Nose, Sinuses, And Skull Base?
The nose and sinuses that surround the nasal cavity may in rare circumstances develop cancer. The nasal cavity is defined by the area within the nose, excluding the skin; whereas the sinuses are collectively known as the paranasal sinuses and include: the maxillary sinuses, ethmoid sinuses, sphenoid sinuses, and the frontal sinuses. The sinuses are air-filled pockets of bone that sometimes can harbor both malignant and benign tumors. Most often, growths within the nasal and paranasal sinuses are benign. However, the most common malignant tumor is squamous cell carcinoma, usually occurring in the maxillary sinus.
What Causes Cancer Of The Nose, Skull Base, And Sinuses?
Nasal and sinus cancer are exceedingly rare, making it difficult to pinpoint the exact causes in most circumstances. As with other cancers of the head and neck, smoking seems to be a risk factor. Researchers also believe that genetics may play a role. Additionally, some research suggests occupational exposures to nickel, chromium, leather, and wood-workers may also cause the development of cancer in this region.
What Are The Signs And Symptoms Of Nasal And Skull Base Cancer?
Sinonasal cancers frequently present with symptoms related to their location within the nasal airway. However, the symptoms are often times non-specific and may mimic other more common conditions.
- Lump in the Neck. Nasal and paranasal sinus cancers may sometimes present as a mass in the neck if the disease has already spread via lymphatics.
- Nose Bleeds. The presence of a tumor within the sinonasal tract may present as bleeding, particularly from one side
- Sinus Problems. Often times the presence of a tumor may result in obstruction that causes infections, usually localizing to one side. Patients may also present with sinus pressure or headaches.
- Vision Problems. Due to the close proximity of the sinonasal tract to the eyes, patients may present with blurry or double vision.
- Nasal Obstruction. Patient’s may report longstanding feelings of nasal congestion or change/loss of smell.
- Neurological Problems. Loss of facial sensation in regions of the face may occur if the tumor has spread to involve nerves.
- Lesions in the Mouth. Cancers may extend into from the sinonasal tract and involve parts of the palate or mouth.
How Do You Diagnose Skull Base Cancer?
In addition to routine history and physical examination, the physician may perform ancillary tests and procedures in order to confirm the presence and type of sinonasal cancer, as well as to determine the presence of second primary cancers (SPC) or the spread of malignant disease elsewhere.
Biopsy. Often times the first step in the diagnosis of sinonasal cancer is to perform a biopsy. Taking a biopsy will confirm the presence of abnormal cells under microscopic view, and is imperative in making the diagnosis of sinonasal cancer.
- In Office Biopsy. If the lesion can be visualized directly it may be determined that an in-office biopsy is the most efficient and effective method of obtaining tissue for analysis. This can be performed under local anesthesia with minimal discomfort to the patient.
- Operative Biopsy: If the area to be biopsied is too difficult to access in the office a biopsy may be performed under general anesthesia in the operating room.
- Lymph Node Biopsy. If a patient presents with a neck mass, particularly in the setting of no identifiable lesion, the physician may sample tissue from the lymph node. There are several types of lymph node biopsy.
- Fine Needle Biopsy (FNB). If the mass can be felt by the clinician, then a small needle can be introduced with an attempt at extracting cells for microscopic assessment. The appearance of abnormal cells will help support the diagnosis of cancer. Sometimes, not enough cells are extracted, and repeat biopsies may need to be performed. This may also be performed with the help of ultrasound or computed tomography (CT) guidance
- Core Biopsy (CB). Similar to the Fine Needle Biopsy, a core biopsy is performed by introducing a larger caliber needle, with the extraction of tissue as opposed to cells. This core biopsy allows for extraction of more tissue and can be more useful, but often times not necessary, as an FNB is sufficient. This can also be done with or without ultrasound or CT-guided assistance
Blood Work. The physician may elect to perform routine blood analysis to assist in determining the presence of sinonasal cancer or other diseases. Blood work may not be necessary, and the decision to obtain blood work is individualized to every patient.
- Liver Function Tests (LFTs): Can be utilized to determine the presence of concurrent liver disease that may be associated with risk factors for the development of sinonasal cancer (alcohol consumption, hepatitis). Furthermore, abnormal values may indicate the presence of metastatic liver disease.
- Complete Blood Count (CBC): This will identify the presence of any anemia that can sometimes be associated with poor nutrition, or chronic illness.
- Nutritional Blood Work: If a patient seems nutritionally depleted, particularly in advanced cases, the clinician may elect to obtain laboratory work up to measure nutrition markers in the blood work. This may assist in determining if a patient requires supplemental nutrition.
Imaging. Often times a physician may elect to obtain imaging that will help in better understanding the presence of cancer and any other underlying issues. Imaging may be performed on the primary site, or of the general region to better define disease extent. The physician may elect to obtain further imaging in situations in which they are concerned for local invasion (e.g. into bone, muscle, adjacent sites), or regional invasion (to the neck).
- Chest X-rays: Chest radiography may be obtained in order to define the presence of disease in the lungs. Often times patients with sinonasal cancer, have a longstanding history of smoking may have associated lesions in their lungs that should be identified.
- Computed Tomography (CT): CT-Scans usually provide a more detailed image of the head and neck region, identifying parts of the tumor that is not readily seen on exam, as well as the presence of regional disease not readily detected (e.g. in the neck). CT-Scans can be obtained with or without contrast. Given the complexity of the region, usually, CT scans are obtained with contrast, to help in identifying the vascular architecture within the neck. However, this is not always necessary, and CT scans may be obtained without contrast in circumstances that preclude patient receiving contrast (iodine allergies, kidney disease).
- Magnetic Resonance Imaging (MRI): MRI can also be utilized with or without contrast in order to provide superior visualization of soft tissue as well as the brain. Often times an MRI may be needed if there are indeterminate findings on other imaging modalities, with a need for more accurate mapping. MRI can also assist in determining if there is involvement of nerves or the eye which is important in counseling patients regarding future directions of targeted therapies.
- 18-Fluorodeoxyglucose Positron Emission Tomography (18-FDG PET): FDG-PET scans may be performed with CT or MRI imaging modalities and are utilized for the identification of regional or distant metastases.
- Ultrasound (US): Ultrasound may be utilized to better characterize neck masses, or used in conjunction with biopsy techniques. US can indicate suspicious characters of lesions that would direct a physician to more aggressive workup (biopsy, excision).
What Are The Types Of Skull Base Cancers?
Sinonasal tumors vary considerably from benign to malignant with treatment highly contingent on pathology, location, and extent of disease. It is important to recognize the different types of malignancies and their different behavioral patterns. The types of cancers can be categorized on the cells that they originate from. Epithelial based cancers come from the skin lining of the sinonasal cavities, whereas non-epithelial based cancers originate from soft tissue and bone.
- Squamous Cell Carcinoma (SCC). These are malignancies that originate from the skin lining inside the nose and sinus cavities. Behavior is highly dependent on the nature of the pathology.
- Salivary Gland Tumors. Like other regions of the head and neck, minor salivary glands may give rise to cancers that have different degrees of aggression. (see Salivary Gland Cancer).
- Mucosal Melanoma. Melanoma, similar to the type of melanoma found in the skin, may also manifest in the sinonasal cavities.
- Esthesioblastoma (olfactory neuroblasatoma). This is a type of cancer that arises from the region of the nose that is responsible for smell detection.
- Sinonasal Undifferentiated Carcinoma. This type of cancer is very aggressive. It is deemed “undifferentiated” because its cell of origin is unclear.
- Lymphoma. Lymphoma may present as a lesion in the sinonasal cavity due to the diffuse distribution of lymphoid tissue.
- Soft Tissue Cancers. Soft tissue cancers may present in the sinonasal cavity, although rare. These involve sarcomas that may arise from muscle, fat, or joint spaces.
How Are Skull Base Cancers Treated?
Depending on the site of disease, the clinical staging, and patient factors (co-morbid health conditions, patient preferences) a patient-specific treatment plan should be outlined. Tumors located within the maxillary sinus and nasal/ethmoid cavities may be managed differently. Furthermore, management of sinonasal malignancies further depends on the pathology, with different management protocols for squamous cell carcinoma, esthesioneuroblastoma, and mucosal melanoma. Broadly speaking there are 3 types of treatment that can be used in combination or separately depending on the type and stage of cancer. The decision to embark on a particular treatment plan should be made involving a multidisciplinary team of physicians (surgeons, radiation oncologists, and medical oncologists) and the patient.
What Surgeries Are Used In Treating Skull Base Tumors?
Surgery may be performed in the treatment of sinonasal malignancies, with the extent and type of surgery guided by the location and degree of local invasion.
- Endoscopic. Tumors limited in the extent of local invasion and to certain subsites can be approached through the use of cameras and instruments introduced into the nose.
- Lateral Rhinotomy. For larger lesions that extend further back in the nose that cannot be easily accessed through endoscopic approaches. This is an approach by making an incision on the side of the nose.
- Anterior Maxillary Punch (Culdwel-Lac). This approach involves entering the sinus through the mouth, drilling a hole into the front of the maxillary sinus.
- Craniofacial Resection. For extensive lesions that are high in the nose or with extensive involvement of the skull base, a craniofacial resection may be performed.
What Other Therapies Are Used In The Treatment Of Skull Base Tumors?
Definitive Radiation (with or without chemotherapy).This type of radiation treatment involves using radiation as the primary mode to treat the tumor. The goal of definitive radiation therapy is the complete removal of all tumor with external sources of radiation.
Adjuvant Radiation (with or without chemotherapy). This refers to the use of radiation in combination with surgery. The goal of adjuvant radiation is to treat any remaining disease after surgical removal (e.g in circumstances with positive margins).
Chemotherapy. The use of systemic medications is used adjunctively with either surgery or radiation and is used to target disease distant from the local site. It is not used as a primary treatment modality as it does not facilitate eradication at the primary site. Chemotherapy is often used in circumstances of advanced disease (Stage III or IV), or when certain risk factors for distant disease are present. Such risk factors include lymph nodes with a disease that have extended out of their capsule (not contained), positive surgical margins, or involvement of nerves and blood vessels.
Induction Chemotherapy. This refers to chemotherapy performed prior to surgery or radiation. This may be used to determine the biological response of the tumor to chemotherapy, as well as “shrink” tumors to a manageable size that can be better removed with surgery or radiation.
Adjuvant Chemotherapy. This refers to chemotherapy given after definitive treatment with another modality was performed (either surgery or radiation).
Concurrent Chemotherapy. This refers to the decision to administer chemotherapy and radiation concurrently after surgery. This may be the case in situations of predictors of aggressive disease on pathology.
Are there any other surgeries or interventions involved in the treatment of head and neck cancers?
If there is any presence of disease within the neck it should be addressed with some type of therapeutic intervention. Positive neck disease is usually treated through surgical resection or radiation of the actual positive nodes, and all intervening nodes in the neck. This is to ensure accurate pathological characterization of the nodes in the neck and to prevent recurrence in the neck (from missed disease).
Elective Neck Interventions. In the absence of any clinical evidence of disease, an elective neck intervention may be performed. This means to treat the neck (with radiation or surgery) due to the potential for “occult” or hidden disease that is not clinically apparent. If there is a high likelihood (>15%) of occult disease, an elective neck dissection may be performed.
Orbital Involvement. Involvement of the eye may necessitate surgical removal of the eye in order to fully eradicate the disease. This should be thoroughly discussed with the surgeon.
Select Relevant Publications
Mofiyinfolu Sokoya, Arash Bahrami, Jason Cohn, Sameep Kadakia, Moustafa Mourad, Yadranko Ducic. Orbital Skull Base Reconstruction with Temporalis Muscle: The Sphenoid Keyhole Technique. CMTR Open. 2018; 02(01): e27-e30. Link to Article.