|
|
||||||||
1 Department of Radiology, Mayo Clinic College of Medicine, Scottsdale,
AZ.
2 Department of Radiology, Brooke Army Medical Center, San Antonio, TX.
3 Department of Radiology, University of CaliforniaSan Diego, San Diego,
CA.
4 Department of Radiology, University of Washington, 4245 Roosevelt Way NE, Box
354755, Seattle, WA 98105-6008.
Received December 28, 2005;
accepted after revision December 28, 2005.
Address correspondence to F. S. Chew.
Abstract
|
|
|---|
Keywords: brain tumors neuroradiology oncologic imaging pineal region spine
|
|
|---|
|
|
|---|
|
|
|---|
|
|
|---|
|
|
|---|
| QUESTION 1 Which statement is TRUE regarding dural arteriovenous fistulas (DAVFs)?
QUESTION 2 Which of the following is TRUE regarding chronic inflammatory demyelinating polyradiculoneuropathy (CIDP)?
QUESTION 3 Ossification of the posterior longitudinal ligament (OPLL) is a form of spine disease that may be classified under which general category?
|
Solution to Question 1
Dural arteriovenous fistulas (DAVFs) are characterized by the presence of
enlarged blood vessels along the surface of the spinal cord. These vessels are
not intramedullary in location. Option A is not the best response.
DAVFs typically occur in middle-aged men, not in the adolescent population.
Option B is not the best response. The common MRI features of DAVFs are
T2 increased signal within the spinal cord, sometimes with spinal cord
enlargement and enhancement. However, these features are nonspecific and may
be confused with other lesions, such as neoplasms, infections, or
demyelination. Option C is not the best response. DAVFs are one of the
treatable causes of chronic, progressive myelopathy
[1]. Option D is the
best response.
Solution to Question 2
Chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) may mimic
neurofibromatosis 2 (NF2) in the brain because enlargement and enhancement of
cranial nerves VII and VIII may simulate bilateral acoustic neuromas.
Option A is the best response. CIDP has a slowly progressive clinical
course that is often misdiagnosed in its initial stages. Option B is
not the best response. The characteristic imaging feature of CIDP on MRI or CT
is enlargement of multiple cranial nerves and nerve roots. Option C is
not the best response. CIDP characteristically involves multiple roots,
extending from the cranial nerves to the sacrum, bilaterally
[2]. Option D is not the
best response.
| QUESTION 4 Which is the most common primary tumor found in the pineal region?
QUESTION 5 At which level will obstruction be in cases of hydrocephalus caused by a pineal region mass?
QUESTION 6 Diabetes insipidus in the presence of a pineal region mass raises concern for which of the following complications?
|
Solution to Question 3
OPLL is a condition in which there is non-inflammatory ossification of the
posterior longitudinal ligament in the spine that may lead to spinal stenosis,
progressive cervical myelopathy, and other complications
[3]. The spinal enthesopathies,
including OPLL, refer to any non-inflammatory calcification or ossification of
the paraspinal ligaments. Option D is the correct answer.
Intervertebral osteochondrosis is a manifestation of degenerative disk disease
that affects the nucleus pulposus and the vertebral endplates. Progressive
disk dehydration and nucleus pulposus degeneration lead to vacuum disk changes
and progressive disk-space collapse. Option A is not the correct
answer. Spondylosis deformans is a manifestation of degenerative disk disease
and is recognized by the formation of osteophytes along the margins of the
vertebral bodies where the annulus fibrosus attaches to the margins of the
vertebral bodies. These osteophytes are so common that they may be considered
to be part of the normal aging process. Option B is not the correct
answer. Synovial osteoarthritis is a degenerative disease of the articular
cartilage in the apophyseal and uncovertebral joints. Synovial osteoarthritis
is particularly common in the apophyseal joints of the lower cervical and
lower lumbar spine and in the uncovertebral joints of the lower cervical
spine. Option C is not the correct answer.
Solution to Question 4
Masses of the pineal region are classified (by the Armed Forces Institute
of Pathology) as germ cell tumors (including germinoma), pineal parenchymal
neoplasms (including pineoblastoma), neoplasms of supporting elements of
adjacent tissues (including glioma), nonneoplastic masses (including
epidermoid), and metastatic neoplasms
[4]. Most pineal tumors occur
in children, and approximately 50% of those are germinomas. Approximately 80%
of intracranial germinomas occur in the pineal region. Germinomas are not
encapsulated and may invade adjacent structures or spread along CSF pathways.
Presentation of germinoma with disseminated disease is not rare. Option
B is the best response.
Solution to Question 5
The CSF spaces are posterolateral and inferior to the pineal region, and
masses in this area result in brainstem compressive symptoms long before
hydrocephalus would develop. Option A is not the best response. The
foramina of Luschka are posterior and inferior to the pineal region. Also,
given the bilateral nature of this structure, obstruction of one foramen of
Luschka would not lead to hydrocephalus. Option B is not the best
response. The aqueduct of Sylvius is immediately anterior to the pineal region
and thus is readily compressed and obstructed once a significant mass develops
[4]. Option C is the
best response. Although a large pineal region mass may cause deformity of the
fourth ventricle, the lesion would first compress the connecting aqueduct of
Sylvius superiorly. Option D is not the best response.
Solution to Question 6
Drop metastases from tumors in the pineal region are not rare
[3], but if they involved the
pons, they would more likely result in defects of cranial nerves VVIII,
and not in diabetes insipidus. Option A is not the best response.
Infiltration of the cerebellum would most likely present with ataxia, visual
disturbances, or both, not diabetes insipidus. Option B is not the best
response. Lesions in the suprasellar subarachnoid region can adversely affect
the hypothalamicpituitaryadrenal hormonal axis, thereby leading
to antidiuretic hormone deficiency. This deficiency results in the inability
of the kidneys to adequately conserve water and is manifested by excessive
thirst and polyuria, symptoms that are similar to those in uncontrolled
diabetes mellitus. However, because no sugar is present, the urine does not
have a sweet taste, hence the name diabetes insipidus. Option C is the
best response. Patients with severe hydrocephalus generally present with
headache, nausea or vomiting, ataxia, and visual disturbances, not diabetes
insipidus. Option D is not the best response.
|
|
|---|
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |