Chordomas

Chordomas may affect people of all ages. Although the median age at diagnosis varies among different studies, a unimodal distribution with a peak incidence around 40–60 years of age is usually reported. Pediatric chordomas are rare, account for less than 5% of the cases, and commonly affect the skull base (see Chapter 36 ). Additionally, skull base chordomas are more common in younger patients (30–40 years), whereas spinal chordomas tend to occur more frequently in older patients (50–60 years).

In terms of gender predilection, it is generally accepted that chordomas have a male predominance, with a ratio of ∼1.5:1. However, the analysis of 400 cases from the Surveillance, Epidemiology and End Results (SEER) database program of the National Cancer Institute of the United States, which evaluated the reported incidence of chordomas in the American population between 1973 and 1995, found that female sex was associated with a greater likelihood of skull base tumors. A female predominance or no gender predilection had also been reported by other authors in more recent surgical series containing solely skull base tumors. Conflicting results were reported in two major pediatric series. Matsumoto et al. have reported a male predominance in a series with 36 pediatric patients, whereas Hoch et al. have reported a female predominance in a series with 73 patients. Last, chordomas are unusual among the African American population.

Chondrosarcomas

Chondrosarcomas may also develop at any age. The analysis of 2890 chondrosarcoma cases from the SEER database program revealed a mean age at the time of diagnosis of 51 years, with the range being 1–102 years, and a male predominance of 1.2:1. However, as the majority of chondrosarcomas enrolled in this analysis arose from the appendicular skeleton (i.e., limbs), these data do not necessarily reflect the demographic peculiarities of chondrosarcomas arising from the axial skeleton (i.e., skull base and spine).

Although the mean age at the time of diagnosis also varies among different studies, skull base chondrosarcomas usually present at younger ages compared with chordomas, with a peak incidence around 20–40 years. Spinal chondrosarcomas, as do spinal chordomas, more often occur in older patients, with a peak incidence around 40–60 years reported in major series. Pediatric chondrosarcomas account for less than 10% of all cases.

Chondrosarcomas of the appendicular skeleton are more common in men than in women. Although most series of skull base tumors have a male to female ratio of ∼2:1, a minority report a slight female predominance or no sex difference. Chondrosarcomas are also unusual in the African American population.

In summary, there are no major demographic differences between patients with chordomas and those with chondrosarcomas. People of all ages may be affected by either tumor, although chondrosarcomas and skull base tumors in general tend to occur at earlier ages and chordomas and spinal tumors in general have a predilection for older patients. Reported findings regarding gender predilection for chordomas and condrosarcomas are mixed, but a male predominance is most commonly reported. Last, both tumors are relatively rare in African Americans.

Skull Base Tumors

The symptoms of skull base chordomas and chondrosarcomas reflect their location and extension. Typically, skull base chordomas are found near the midline as they arise from the sphenooccipital synchondrosis of the clival bone. Chondrosarcomas, on the other hand, are usually paramedian, as they arise from the sphenopetroclival synchondrosis of the petroclival fissure. Both tumors may extend into multiple intracranial and extracranial compartments. Cranial neuropathies and pain are the most common presenting symptoms.

As the clivus is commonly compromised by these neoplasms, intermittent or permanent diplopia due to dysfunction of the sixth cranial nerve, most likely near Dorello canal, is the initial symptom of most patients. Headache, from bone erosion or compression of adjacent neural structures, is often occipital or occipitocervical and may be aggravated by change in neck position.

Tumors extending superiorly may affect the pituitary gland and cause hypopituitarism. Further extension to the suprasellar space may cause diabetes insipidus, hypopituitarism, and visual impairment from involvement of the pituitary stalk and the optic apparatus. Chordomas and chondrosarcomas can also extend laterally to invade the cavernous sinus and Meckel cave causing cranial neuropathies evident in ptosis (third nerve), ophthalmoplegia (third, fourth, and sixth nerve), and facial numbness (fifth nerve). Patients with tumor involvement of the cavernous sinus and Meckel cave may also complain of retro-orbital pain and trigeminal neuralgia. Proptosis may be casued by intraorbital invasion.

Tumors extending inferiorly and into the posterior fossa may also cause cranial neuropathies, such as diplopia (6th nerve), facial weakness (7th nerve), tinnitus, vertigo and hearing loss (8th nerve), swallowing difficulties and hoarseness (9th and 10th nerves), and tongue weakness (12th nerve). These tumors, particularly chondrosarcomas, extending into the petrous bone may also cause these symptoms. Gait disturbance, ataxia, dysmetria, and motor weakness (e.g., hemiparesis or tetraparesis) may be caused by larger tumors compressing the brainstem and cerebellum. Further extension down to the foramen magnum and upper cervical region may cause torticollis and neck pain and stiffness; exacerbation of such pain with movement may indicate instability from tumor erosion of bone and ligaments of the craniocervical junction.

Extension of skull base chordomas and chondrosarcomas into extracranial compartments may cause region-specific symptoms: involvement of the nasal cavities, paranasal sinuses, oral cavity, and parapharyngeal space can prompt nasopharyngeal symptoms, such as nasal obstruction, nasal drainage, epistaxis, hyposmia, throat fullness, eustachian tube dysfunction, and dysphagia, and extension into the infratemporal fossa may cause trismus and weakness of the masticatory muscles by affecting the pterygoid muscles and mandibular division of the trigeminal nerve, respectively. Very rarely, seizures, signs of intracranial hypertension, and sudden neurological deterioration due to acute intratumoral and subarachnoid hemorrhage may be the initial clinical presentation.

Spinal Tumors

The symptoms of spinal chordomas and chondrosarcomas resemble those of other spinal and epidural tumors. Chordomas arise in the vertebral bodies and, most commonly, the sacrum, whereas chondrosarcomas occur predominantly in the thoracic spine, most commonly in the posterior elements. Both tumors may extend significantly into the adjacent soft tissues, epidural space, and spinal canal and cause a variety of symptoms depending on their location in either the sacrum or the mobile spine. Local pain, from bone erosion, is the initial symptom in the vast majority of patients (∼80%). Nocturnal back pain not responsive to bed rest is very characteristic. A palpable mass, reported as the presenting symptom in up to 40% of the cases; local tenderness; or swelling may also signal tumor, especially in the sacral region.

Neurological symptoms from spinal chordomas are more common late in the clinical course of the disease. In contrast, neurological deficits are the presenting symptoms in about 50% of patients with spinal chondrosarcomas. Since many spinal chondrosarcomas arise from the posterior elements of a vertebra, early appearance of symptoms may reflect either tumor proximity to a nerve root (causing radiculopathy) or expansion into the spinal canal, a path of less resistance (causing myelopathy or multiple radiculopathies).

Patients may present with radicular pain, neurogenic claudication, arm or leg weakness, deep tendon reflex changes, tone abnormalities, sensory deficits, paresthesias, dysesthesias, sphincter disturbances of bowel or bladder, and gait ataxia. Cervical spine tumors with significant extraspinal extension may cause Horner syndrome. Sacral chordomas may cause constipation as a result of rectal compression by anterior extension of the tumor into the pelvis via the ventral sacral foramina.

Pediatric Cases

The presenting symptoms of pediatric skull base chordomas and chondrosarcomas are very similar to those observed in the adult population with the caveat that signs of intracranial hypertension and brainstem dysfunction (e.g., pyramidal and long tract signs) occur more frequently in children; these often herald greater severity of the disease. Symptoms in children often progress more rapidly than in adults, a reflection of the higher frequency of aggressive, histologically atypical tumors. Lower cranial nerve palsies (9th through 12th nerves) are also more characteristic of pediatric skull base tumors.

Local pain is the most common clinical presentation of sacral tumors in children; constipation is also common. Neurological symptoms, such as saddle anesthesia and sphincter disturbances, may be present and are associated with poor outcomes. A mass palpable on rectal examination occurs in almost all cases of pediatric sacral chordomas.

In summary, the clinical presentations of chordomas and chondrosarcomas are quite similar, particularly in the skull base. Differentiation between these tumors there solely by clinical history and neurological examination is virtually impossible. For a spinal tumor, occurrence of neurological symptoms earlier in the course of the disease favors the diagnosis of chondrosarcomas.