Differential Diagnosis: Posterior Fossa Ependymoma
Ependymomas are the third most common type of brain tumor in children following
astrocytoma and medulloblastoma. They are relatively rare. They account for 6-12% of brain tumors in
children less than 18 years of age, but 30% of brain tumor in children less than 3 years of age.
Approximately, 70% of ependymomas in childhood occur in the posterior fossa.
Ependymomas are tumors that arise from the cells lining the ventricles and the central canal
within the spinal cord. The WHO classified epedymomas in to four types, namely: myxopapillary
ependymomas, subependymomas, ependymomas and anaplastic ependymomas. Symptoms occurs
depending on the location of the tumor. For posterior fossa ependymoma or the classic ependymoma
are fairly well delineated tumors that can arise anywhere in the central nervous system. The tumor
tends to grow relatively slowly and displace, rather than invade adjacent brain or spinal cord tissue.
They grow outside the ventricle through paths of least resistance within the brain. Posterior fossa
ependymomas spread to other parts of the brain or spinal cord through the CSF. They rarely metastasize
to sites outside of the central nervous system.
Symptoms that are produced in ependymoma depend on the location of the tumor. The three
major locations are the posterior fossa, supretentorium and the spinal cord. In children, about 90% arise
within the brain in the posterior fossa, in or around the fourth ventricle.
Tumors in the posterior fossa can lead to obstruction of cerebrospinal fluid flow, and children
can develop signs and symptoms of increased intracranial pressure such as headache, vomiting, head tilt
and double vision. Tumors that arise on the floor of the fourth ventricle are associated with torticollis
and ataxia. Posterior fossa tumors may lead to cerebellar dysfunction, resulting in balance and gait
disturbances that frequently are associated with vomiting and lower cranial nerve finding such as
diplopia, facial weakness, tinnitus, vertigo and hearing loss. On physical examination, increased
intracranial pressure may result to papiledema on fundoscopic examination; palsy of the CN VI, resulting
in the inability to abduct one or both eyes; setting sun sign due to impaired upgaze and a forced
downward deviation. School-aged patient’s with ependymoma usually complian of vague, intermittent
headaches and fatigue with an accompanying declining academic performance and exhibit personality
changes.
The patient is a 10 year old, school-age who present with intermittent headaches and vomiting.
The headache projectile vomiting can be caused by an increased intracranial pressure on the patient.
Tumors such as ependymomas in the posterior may cause an obstruction in the in the flow of the
cerebrospinal fluid. Another evidence of an increased ICP in the patient is a possible CN VI that may
cause the patient unable or a limited lateral eye movement on the left and could also possibly explain
the positive horizontal nystagmus on neurologic examination. The time progression of symptoms is also
in accordance in the development of ependymoma because they grow relatively slow and rarely spread
to other sites.
This diagnosis is less likely due to lack of cerebellar involvement on the patient. Cerebellar
dysfunction is common due to the location of the tumor, in the posterior fossa. Balance is commonly
affected such as gait disturbances and lower cranial nerve affectations such as diploplia, facial weakness,
tinnitus, vertigo and hearing loss. It is also less likely due to the timing of headache. the patient present
with headache that is worse in the late afternoon. Headache of increased ICP is pain present in upon
rising, relieved by vomiting and gradually decreasing during the day. A CT scan done on the patient
revealed a slight enhancing heterogenous hyperdense lesion is least likely of ependymomas.
Ependymomas typically appears as hyperdense and homogeneously contrast enhancing lesion.
POWERPOINT:
Differential Diagnosis:
POSTERIOR FOSSA EPENDYMOMA
Incidence:
-
Third most common brain tumor in children next to medulloblastoma and astrocytoma
Account for 10% of children tumor
Age: mean age of diagnosis- 5-6 years with 30% of cases occurring in children <3 years
Sex: male:female – 1:1
Posterior fossa ependymoma – 70% (location)
Clinical Presentation:
History:
-
-
Symptoms of increased intracranial pressure:
 morning headaches, vomiting, and lethargy
 school-aged: vague intermittent headache and fatigue, declining academic
performance, personality changes
 Infants: irritability, anorexia, and developmental delay or regression.
cerebellar dysfunction:
 resulting in balance and gait disturbances that frequently are associated with vomiting
and lower cranial nerve findings such as diplopia, facial weakness, tinnitus, vertigo, and
hearing loss.
Physical Examination:
-
increased ICP
 funduscopic examination reveals papilledema
 Palsy of cranial nerve VI, resulting in the inability to abduct one or both eyes
 setting sun sign
-
truncal steadiness, upper extremity coordination, and gait may be observed with posterior fossa
tumors.
impair function of the lower cranial nerves (primarily VI, VII, VIII, IX, and X).
CT- Scan
-
typically appears as hyperdense and homogeneously contrast-enhancing lesion arising from, or
adjacent to, the ventricular system.
++++ lang… ung rule-in rule-out is discussed above… ok lng iedit..