The Radiology Assistant : Brain Tumor - Systematic Approach10/31/13, 11:22 AM Brain Tumor - Systematic Approach Robin Smithuis and Walter Montanera Radiology Department of the Rijnland hospital, Leiderdorp, the Netherlands and the Division of Neuroradiology of the St. Michael's Hospital, University of Toronto, Canada Publicationdate July 2, 2008 This review is based on a presentation given by Walter Montanera and was adapted for the Radiology Assistant by Robin Smithuis. In this review a systematic approach for the analysis of a possible brain tumor is described. By clicking on one of the subjects in the list on the left, you will go directly to this item. by Robin Smithuis and Walter Montanera Introduction When we analyze a potential brain tumor, there are many questions that need to be answered. Since different tumors occur in different age groups we first of all need to know the age of the patient. Next we need to know where the lesion is located - is it intra- or extra-axial and in what anatomical compartment does it lie? Is it located in the sellar or pontocerebellar region for example? Is it a solitary mass or is there multi-focal disease? On CT and MR we look for tissue characteristics like calcifications, fat, cystic components, contrast enhancement and signal intensity on T1WI, T2WI and DWI. Most brain tumors are of low signal intensity on T1WI and high on T2WI. Therefore high signal intensity on T1WI or low signal on T2WI can be an important clue to the diagnosis. Finally we have to consider the possibility that we are dealing with a lesion that simulates a tumor like an abscess, MS-plaque, vascular malformation, aneurysm or an infarct with luxury perfusion. http://www.radiologyassistant.nl/en/p47f86aa182b3a Page 1 of 29 The Radiology Assistant : Brain Tumor - Systematic Approach 10/31/13, 11:22 AM Incidence of CNS tumors Roughly one-third of CNS tumors are metastatic lesions, one third are gliomas and one-third is of non-glial origin. Glioma is a non-specific term indicating that the tumor originates from glial cells like astrocytes, oligodendrocytes, ependymal and choroid plexus cells. Astrocytoma is the most common glioma and can be subdivided into the low-grade pilocytic type, the intermediate anaplastic type and the high grade malignant glioblastoma multiforme (GBM). GBM is the most common type (50% of all astrocytomas). The non-glial cel tumors are a large heterogenous group of tumors of which meningioma is the most common. Age distribution The age of the patient is an important factor for the differential diagnosis. Specific tumors occur under the age of 2, like choroid plexus papillomas, anaplastic astrocytomas and teratomas. In the first decade medulloblastomas, astrocytomas, ependymomas, craniopharyngeomas and gliomas are most common, while metastases are very rare. When they do occur at this age, metastases of a neuroblastoma are the most frequent. In adults about 50% of all CNS lesions are metastases. Other common tumors in adults are astrocytomas, glioblastoma multiforme, meningiomas, oligodendrogliomas, pituitary adenomas and schwannomas. Astrocytomas occur at any age, but glioblastoma multiforme is mostly seen in older people. http://www.radiologyassistant.nl/en/p47f86aa182b3a Page 2 of 29 but it is the most common primary intra-axial tumor in the adult. Particularly in the posterior fossa. then the lesion is not actually a brain tumor. in an adult an intra-axial tumor will be a metastasis or astrocytoma in 75% http://www. but derived from the lining of the brain or surrounding structures. 11:22 AM Although cancer is rare in children. The most common supra. the first thing we want to know is whether the mass lies in. Tumor spread Intra. Most of the tumors in children are located infratentorially. The most common tumors in adults are listed in the table on the left.Systematic Approach 10/31/13. Supratentorially. metastases should be in the top 3 of the differential diagnostic list. Note that metastases are by far the most common. brain tumors are the most common type of childhood cancer after leukemia and lymphoma.or outside of the brain. Eighty percent of these extra-axial lesions will be either a meningioma or a schwannoma. If it is outside the brain or extra-axial. Hemangioblastoma is an uncommon tumor.nl/en/p47f86aa182b3a Page 3 of 29 .The Radiology Assistant : Brain Tumor . It is important to realize that 50% of metastases are solitary.versus Extraaxial When we study an intracranial mass.radiologyassistant.and infratentorial tumors are listed in the table on the left. On the other hand. followed by gliomas. metastases are also the most common tumors. The subarachnoid vessels that run on the surface of the brain are displaced by the lesion (blue arrow). hyperostosis of adjacent bone and homogeneous enhancement Schwannoma in CPA-region with typical features of an extraaxial tumor (T2WI) On the left an example of a meningioma with a broad dural base and a dural tail of enhancement.Systematic Approach 10/31/13. There is gray matter between the lesion and the white matter (curved red arrow).The Radiology Assistant : Brain Tumor . Extra-axial tumors are not derived from brain tissue and do not have a blood-brain-barrier. In the region of the CPA 90% of the extra-axial tumors are schwannomas. This may also occur in other extra-axial tumors. 11:22 AM of cases. The subarachnoid space is widened because growth of an extra-axial lesion tends to push away the brain. There is hyperostosis in the adjacent bone and the lesion enhances homogeneously. but it is less common. There is a CSF cleft (yellow arrow). chondrosarcomas and metastases.nl/en/p47f86aa182b3a Page 4 of 29 . so most of them enhance homogeneously. as is seen in meningiomas and other tumors. The T2W-images show a schwannoma located in the cerebellopontine angle (CPA). http://www. All these signs indicate that this is a typical extra-axial tumor. This case nicely demonstrates the typical signs of an extra-axial tumor. Another sign of an extra-axial origin are bony changes.radiologyassistant. Coronal enhanced T1WI. Another sign of an extra-axial origin is a broad dural base or a dural tail of enhancement as is typically seen in meningiomas. Bony changes are seen in bone tumors like chordomas. Meningioma with dural tail. They can also be secondary. 11:22 AM Intra. but sometimes it can be very difficult and imaging in multiple planes may be necessary.radiologyassistant. there is gray matter on the anteromedial and posteromedial side of the lesion (red arrow). Local tumor spread (1) Astrocytomas spread along the white matter tracts and do not respect the bounderies of the lobes. in many cases the tumor is actually larger than can be depicted with MR. Oligodendrogliomas typically show extension to the cortex. This indicates that the lesion is intra-axial. If the lesion was extra-axial the gray matter should have been pushed away.Systematic Approach 10/31/13. This lesion surely has the appearance of a meningioma: these tumors can be hypointense on T2 due to a fibrocollageneous matrix or calcifications and frequently produce reactive edema in the adjacent white matter of the brain. The tumor in the case on the left was thought to be a falcine meningioma. Subarachnoid seeding Some tumors show subarachnoid seeding and http://www. This proved to be a melanoma metastasis.The Radiology Assistant : Brain Tumor . . However. Because of this infiltrative growth. extra-axial and was presented for surgery.e. i. Ependymomas of the fourth ventricle in children tend to extend through the foramen of Magendie to the cisterna magna and through the lateral foramina of Luschka to the cerebellopontine angle (figure).vs Extra-axial (2) The differentiation between intra-axial versus extra-axial is usually straight forward.nl/en/p47f86aa182b3a Page 5 of 29 Melanoma metastasis: T2WI and T1WI Ependymoma with extension to the prepontine area (blue arrows) and into the foramen magnum (red arrow). ependymomas. The tumor is situated in the pterygopalatine fossa and extends into the orbit. Primitive neuroectodermal tumours (PNET) form a rare group of tumors. There is homogeneous enhancement with a broad dural tail. One of the most important roles of imaging is to assess the extent of a tumor. due to their infiltrative growth.Systematic Approach 10/31/13. This is seen in PNET. This is shown in the case on the left in a patient who presented with multiple cranial nerve abnormalities. These include medulloblastomas and pineoblastomas. which have more mass effect due to their expansive growth.nl/en/p47f86aa182b3a Page 6 of 29 . 11:22 AM form tumoral nodules along the brain and spinal cord. which develop from primitive or undifferentiated nerve cells. This is not the case with metastases and extraaxial tumors like meningiomas or schwannomas. On the left is an image of a diffusely infiltrating http://www. This is typical for a meningioma. It also spreads anteriorly into the middle cranial fossa Low grade astrocytoma Local tumor spread (2) Another important consideration is the effect on the surrounding structures. On the images we see an extra-axial tumor in the region of the left cavernous sinus. Only by studying all the images we do appreciate that the actual extent of the tumor is greater than expected. Primary brain tumors are derived from brain cells and often have less mass effect for their size than you would expect.The Radiology Assistant : Brain Tumor . GBMs. oligodendrogliomas and choroid plexus papillomas. lymphomas.radiologyassistant. multicentric glioblastomas and gliomatosis cerebri can be multifocal. Page 7 of 29 LEFT: Metastases. Epidermoid cysts can cross the midline via the subarachnoid space. ependymomas. Some tumors can be multifocal as a result of seeding metastases: this can occur in medulloblastomas (PNET-MB). RIGHT: Multiple meningiomas and a schwannoma in a patient with Neurofibromatosis II http://www. Radiation necrosis can look like recurrent GBM and can sometimes cross the midline.nl/en/p47f86aa182b3a . Tumors and tumor-like masses that cross the midline Multifocal disease Multiple tumors in the brain usually indicate metastatic disease (figure). There is no enhancement so this would probably be a low-grade astrocytoma. Meningiomas and schwannomas can be multiple. but some brain tumors like lymphomas.Systematic Approach 10/31/13. 11:22 AM intra-axial tumor occupying most of the right hemisphere with only a minimal mass effect. MS can also present as a mass lesion in the corpus callosum. This is typical for the infiltrative growth seen in primary brain tumors. Midline crossing The ability of tumors to cross the midline limits the differential diagnosis. GBMs and oligodendrogliomas. Primary brain tumors are typically seen in a single region. Lymphoma is usually located near the midline. Meningioma is an extra-axial tumor and can spread along the meninges to the contralateral side.radiologyassistant. Glioblastoma multiforme (GBM) frequently crosses the midline by infiltrating the white matter tracts of the corpus callosum.The Radiology Assistant : Brain Tumor . A DNET is a rare benign neoplasm. ependymomas. Multiple brain tumors can be seen in phacomatoses: Neurofibromatosis I: optic gliomas and astrocytomas Neurofibromatosis II: meningiomas. abscesses) or demyelinating diseases like MS can also present as multifocal disease. infections (septic emboli. The differential diagnosis for these cortical based tumors includes oligodendroglioma. Patients with a cortically based tumor usually present with complex seizures. On the left a 45-year-old female with a stable seizure disorder (complex-partial) for 15 years. however. This is a ganglioglioma.nl/en/p47f86aa182b3a Page 8 of 29 . These cortically based tumors have to be differentiated from non-tumorous lesions like cerebritis. usually in a cortical and temporal location.Systematic Approach 10/31/13. choroid plexus papillomas (figure) Tuberous Sclerosis: subependymal tubers. cortically based tumor. ependymomas von Hippel Lindau: hemangioblastomas Many non-tumorous diseases like small vessel disease. There is a non-enhancing. http://www. 11:22 AM especially in neurofibromatosis type II. spread to or are located in the gray matter. herpes simplex encephalitis. ganglioglioma and Dysembryoplastic Neuroepithial Tumor (DNET). intraventricular giant cell astrocytomas.radiologyassistant.The Radiology Assistant : Brain Tumor . Cortical based tumors Most intra-axial tumors are located in the white matter. Some tumors. infarction and post-ictal changes. The differential diagnosis includes DNET and pilocytic astrocytoma. High density Fat has a low density on CT (. On MR. Fat within a tumor is seen in lipomas. fat has a high signal intensity on both T1and T2WI.The Radiology Assistant : Brain Tumor . The differential diagnosis includes a malignant astrocytoma or a glioblastoma.Calcification . . as this indicates the presence of fat. which indicates that this is an infiltrating tumor. slow flow etc.nl/en/p47f86aa182b3a Page 9 of 29 Ruptured dermoid cyst. Although this is a large tumor there is only limited mass effect on surrounding structures. When you see high signal on T1WI always look for chemical shift artefact. melanin. complained of headache and neck pain.Cyst . Coronal T1WI (left) and NECT (right). 11:22 AM On the left are images of a 52-year-old female who. which extends all the way to the cortex. The most likely diagnosis is oligodendroglioma.radiologyassistant. On sequences with fat suppression fat can be differentiated from high signal caused by subacute hematoma. There is a recent onset of tonic-clonic seizures. The chemical shift artefact occurs as alternating bands of high and low signal on the boundaries of a lesion and is seen only in the frequency encoding direction. over the period of one year.100HU). CT and MR Characteristics Fat . The CT shows a mass with calcifications. dermoid http://www.Systematic Approach 10/31/13. but is easily seen on CT. 11:22 AM cysts and teratomas. are far more common. On the left is an image of a calcified mass in the suprasellar region.Systematic Approach 10/31/13. When we think of a calcified intra-axial tumor.The Radiology Assistant : Brain Tumor . we think oligodendroglioma since these tumors nearly always have calcifications. On the left a patient with the classical findings of a ruptured dermoid cyst. but instead it 'explodes' the calcifications of the pineal gland. cystic tumors arising from remnants of Rathke's cleft. The calcification is not appreciated on the MR images. colloid cyst and PNET-MB (medulloblastoma). The calcification and the extension of the tumor to the cortex are very typical for an oligodendroglioma. Oligodendroglioma with calcification (PDWI and CT) http://www. A pineocytoma itself does not calcify. although less frequently calcified.nl/en/p47f86aa182b3a Page 10 of 29 .radiologyassistant. They are located the (supra)sellar region and primarily seen in children with a small second peak incidence in older adults. causing obstructive hydrocephalus. An astrocytoma should be in the differential. calcified. Some tumors can have a high density on CT. squamous epithelial. Craniopharyngiomas are slow growing. extra-axial. On the left are images of a tumor with a small calcification. Calcification Calcification is seen in many CNS tumors (Table). This location in the suprasellar region and the calcification are typical for a craniopharyngioma. This is typically seen in lymphoma. since astrocytomas. . However an intraaxial calcified tumor in the brain is more likely to be an astrocytoma than a oligodendrogliomas. neuroenteric and neuroglial cysts. It would be impossible to operate this tumor and preserve the patient's vision.radiologyassistant. In the middle a neuroenteric cyst with the contents of which have the same signal intensity as CSF. In order to determine whether a lesion is a cyst or cystic mass look for the following characteristics: Morphology Fluid/fluid level Content usually isointense to CSF on T1. This patient was booked for decompression. On the coronal and sagittal TW1I there is a large mass centered around the sella with a broad dural base. arachnoid.Systematic Approach 10/31/13. The enhancement in GBM is usually more irregular. Tumor necrosis may sometimes look like a cyst. was it appreciated how densely calcified this tumor is. These include epidermoid.The Radiology Assistant : Brain Tumor . dermoid. Only after the CT was performed. On the far left a craniopharyngioma with an enhancing rim surrounding the cystic component. but it is never completely isointense to CSF. Even enlarged perivascular spaces of Virchow Robin can simulate a tumor. There is extension into the sella. http://www.nl/en/p47f86aa182b3a Page 11 of 29 . 11:22 AM Calcified meningioma On the left are images of a patient with progressive visual loss. T2 and FLAIR DWI: restricted diffusion An arachnoid cyst is isointense to CSF on all sequences. On the right a glioblastoma multiforme (GBM) with a central cystic component. Cystic versus Solid There are many cystic lesions that can simulate a CNS tumor. The patient in the middle has a glioblastoma multiforme. These tumors will be dark on T2WI. which caused a hemorrhage in the splenium of the corpus callosum. On the left is a list of causes for T1-shortening. On the right is a patient with a metastasis of a melanoma. On the left are some images of tumors with high signal intensities on T1WI. Paramagnetic effects cause a signal drop and are seen in tumors that contain hemosiderin. The classic examples are CNS lymphoma and PNET (also hyperdense on CT). Low on T2 Most tumors will be bright on T2WI due to a high water content. On the far left images of a patient who presented with apoplexy. Calcifications are mostly dark on T1WI. Especially on gradient echo images slow flow can be seen as bright signal on T1WI and should not be confused with enhancement. The differential diagnosis of calcified tumors was discussed above.radiologyassistant. The high signal intensity is due to the melanin content. 11:22 AM High on T1 Most tumors have a low or intermediate signal intensity on T1WI. The high signal is due to hemorrhage in a pituitary macroadenoma. This is particularly pronounced on gradient echo images. remember that high signal is not always enhancement. Proteinaceous material can be dark on T2 dehttp://www.The Radiology Assistant : Brain Tumor . Calcifications are mostly dark on T2WI.Systematic Approach 10/31/13.nl/en/p47f86aa182b3a Page 12 of 29 . Exceptions to this rule can indicate a specific type of tumor. When tumors have a low water content they are very dense and hypercellular and the cells have a high nuclear-cytoplasmasmic ratio. but depending on the matrix of the calcifications they can sometimes be bright on T1. If you only do an enhanced scan. A classic example of this is the colloid cyst.nl/en/p47f86aa182b3a Page 13 of 29 . PNET typically has a high nuclearcytoplasmic ratio. Flow voids are also dark on T2 and indicate the presence of vessels or flow within a lesion. This is seen in tumors that contain a lot of vessels like hemangioblastomas. Meningiomas are mostly of intermediate signal. Melanoma metastases have a low SI on T2WI as a result of the melanin. but another. location is in the region of the pineal gland. 1. but also in non-tumorous lesions like vascular malformations. GBM can have a low SI on T2WI because sometimes they have a high nuclearcytoplasmic ratio.The Radiology Assistant : Brain Tumor . On the left some examples of tumors with a low signal intensity on T2WI. less common.. 2. 11:22 AM pending on the content of the protein itself. Most GBM's. 4. 3. 5. They can have a low SI on T2WI if they are very dense and hypercellular or when they contain calcifications.Systematic Approach 10/31/13. however. http://www. They can have a high SI on T2WI if they contain a lot of water. are hyperintense on T2WI.radiologyassistant. PNET is mostly located in the region of the 4th ventricle. Mucinous metastases can have a low SI on T2WI because they often contain calcifications. radiologyassistant. Enhancement http://www. resulting in a high signal on DWI. Perfusion depends on the vascularity of a tumor and is not dependent on the breakdown of the blood-brain barrier.Systematic Approach 10/31/13.nl/en/p47f86aa182b3a Page 14 of 29 . The amount of perfusion shows a better correlation with the grade of malignancy of a tumor than the amount of contrast enhancement. In cerebral abscesses the diffusion is probably restricted due to the viscosity of pus.The Radiology Assistant : Brain Tumor . Perfusion Imaging Perfusion imaging can play an important role in determining the malignancy grade of a CNS tumor. This results in a normal. High intensity on DWI indicates restriction of the ability of water protons to diffuse extracellularly. epidermoid cysts and acute infarction (due to cytotoxic edema). In most tumors there is no restricted diffusion even in necrotic or cystic components. low signal on DWI. Restricted diffusion is seen in abscesses. 11:22 AM Diffusion weighted imaging Normally water protons have the ability to diffuse extracellularly and loose signal. There is also no blood-brain barrier in the pituitary. found incidentally. The reason for this is that tumor cells blend with the normal brain parenchyma where the blood brain barrier is still intact. 11:22 AM Blood brain barrier The brain has a unique triple layered blood-brain barrier (BBB) with tight endothelial junctions in order to maintain a consistent internal milieu. These lesions include like infections.The Radiology Assistant : Brain Tumor . There was no enhancement and the DWI was normal. http://www.even beyond the area of edema. since the infiltrating tumors cells are within the normal-appearing brain tissue. demyelinating diseases (MS) and infarctions. Tumor cells can be found beyond the enhancing margins of the tumor and beyond any MR signal alteration . This was diagnosed as a low-grade astrocytoma. Therefore they will enhance.radiologyassistant.nl/en/p47f86aa182b3a Page 15 of 29 . On the left is an image of a 42 y/o male with mild head trauma. Extra-axial tumors such as meningiomas and schwannomas are not derived from brain cells and do not have a blood-brain barrier. Some non-tumoral lesions enhance because they can also break down the BBB and may simulate a brain tumor. Contrast will not leak into the brain unless this barrier is damaged. Contrast enhancement cannot visualize the full extent of a tumor in cases of infiltrating tumors.Systematic Approach 10/31/13. pineal and choroid plexus regions. Enhancement is seen when a CNS tumor destroys the BBB. During follow-up there was a slight increase in size. On the T2WI there is a lesion in the left temporal lobe. like gliomas. It is not possible to resect such a lesion. As discussed above. it is a sign of malignant transformation. In general.like astrocytomas.nl/en/p47f86aa182b3a . it recently has been shown that tumor angiogenesis as shown by perfusion MR correlates better with tumor grade than enhancement after the administration of intravenous contrast. The amount of enhancement depends on the amount of contrast that is delivered to the interstitium. oligodendrogliomas and glioblastoma multiforme . the better the interstitial enhancement will be.The Radiology Assistant : Brain Tumor . On the left is an image of an intra-axial tumor in an adult. LEFT: Schwannoma extending into the middle cranial fossa with homogeneous enhancement RIGHT: Primary Lymphoma known for its vivid enhancement No enhancement is seen in: Low grade astrocytomas Cystic non-tumoral lesions: Dermoid cyst Epidermoid cyst Arachnoid cyst Low grade astrocytoma. Therefore when during the follow up of a lowgrade glioma the tumor starts to enhance. No enhancement. It is centered in the temporal lobe and involves the cortex.radiologyassistant. but they enhance vividly. The optimal timing is about 30 minutes and it is better to give contrast at the start of the examination and to do the enhanced T1WI at the end. Gangliogliomas and pilocytic astrocytomas are the exceptions to this rule: they are low-grade tumors. 11:22 AM Low grade tumors with enhancement: ganglioglioma (left) and a pilocytic astrocytoma (right) In gliomas ..enhancement usually indicates a higher degree of malignancy.Systematic Approach 10/31/13. the longer we wait. Although there is massive infiltrative growth involving a large part of the right cerebral hemiPage 16 of 29 http://www. Systematic Approach 10/31/13. Homogeneous enhancement can be seen in: Metastases Lymphoma Germinoma and other pineal gland tumors Pituitary macroadenoma Pilocytic astrocytoma and hemangioblastoma (only the solid component) Ganglioglioma Meningioma and Schwannoma Patchy enhancement can be seen in: Metastases Oligodendroglioma Glioblastoma multiforme Radiation necrosis GBM with patchy enhancement and cystic component with ring enhancement On the left is an example of a glioblastoma multiforme (GBM). This is because gliomas grow infiltratively into normal brain . Page 17 of 29 http://www. but only parts of it enhance.initially without any MR changes. Notice that there is also a cystic component with ring enhancement. There is no enhancement.nl/en/p47f86aa182b3a .radiologyassistant. The enhancement indicates that this is a highgrade tumor. there is only minimal mass effect. These features are typical for a low-grade astrocytoma. 11:22 AM sphere. The tumor cells probably extend beyond the area of edema as seen on the FLAIR image.The Radiology Assistant : Brain Tumor . All these findings are typical for a GBM. This indicates that there is marked infiltrative growth.Systematic Approach 10/31/13. There is patchy enhancement. It is also seen in non-tumorous lesions like abscesses. On the left three different ring enhancing lesions. Notice the heterogeneity on both T2WI and FLAIR.The Radiology Assistant : Brain Tumor . http://www. Virtually no other tumor behaves in this way.radiologyassistant.nl/en/p47f86aa182b3a Page 18 of 29 . 11:22 AM Patchy enhancement (2) On the left are images of a tumor located in the right hemisphere. Ring enhancement Ring enhancement is seen in metastases and high-grade gliomas. a characteristic typical for gliomas. Although is a large tumor. After the administration of contrast the two meningiomas and the schwannoma are easily seen. the mass-effect is limited. Conspicuity of tumors with contrast The case on the left demonstrates the value of Gadolinium in the conspicuity of tumors. some MS-plaques and sometimes in an old hematomas. This is a patient with Neurofibromatosis II. along the folia of the cerebellum (yellow arrow) and along the fifth intracranial nerve (blue arrow) in a patient with leptomeningeal metastases. chondrosarcoma. 11:22 AM Leptomeningeal metastases Leptomeningeal metastases are usually not seen without the administration of intravenous contrast. These tumors either arise from extracranial structures like the sinuses (sinonasal carcinoma). http://www.radiologyassistant. while chondrasarcoma usually arises off the midline. The case on the left demonstrates the abnormal enhancement along the brainstem. fibrous dysplasia).nl/en/p47f86aa182b3a Page 19 of 29 . Differential diagnosis for specific anatomic area Skull base Common skull base tumors are listed in the table on the left. or from the skull base itself (chordoma.Systematic Approach 10/31/13. Chordoma is usually located in the midline.The Radiology Assistant : Brain Tumor . 11:22 AM On the left a midline tumor arising from the clivus.radiologyassistant. http://www.The Radiology Assistant : Brain Tumor . This is the typical presentation of a chordoma. The differential diagnosis would include a metastasis and a chondrosarcoma.nl/en/p47f86aa182b3a Page 20 of 29 .Systematic Approach 10/31/13. Chondrosarcomas can be located in the midline and chordomas are sometimes located off midline but those cases are exceptional. This is a typical presentation for a chondrosarcoma.Systematic Approach 10/31/13. The differential diagnosis would include a metastasis and a paraganglioma.The Radiology Assistant : Brain Tumor .radiologyassistant. http://www.nl/en/p47f86aa182b3a Page 21 of 29 . 11:22 AM On the left another skull base tumor located off midline. The Radiology Assistant : Brain Tumor . Continue with the MR images. There is an enhancing mass anterior to the skull base and also in the region of the right cavernous sinus.nl/en/p47f86aa182b3a Page 22 of 29 . In the bone window setting there is sclerosis of the skull base. particularly in the region of the clivus. http://www. 11:22 AM On the left an example of a Skull Base Paraganglioma.radiologyassistant.Systematic Approach 10/31/13. First study the images. than continue. On the left CT images of a 58-year-old male with a gradual onset of right facial pain and numbness and a recent onset of double vision. These findings are very specific for a craniopharyngeoma. There is an enhancing mass anterior to the clivus. There are other components that show enhancement. On the NECT we can see that it contains calcium. A normal clivus is bright on T1WI as a result of the fatty bone marrow. On the left are images of a mass in the suprasellar cistern.radiologyassistant.although this would be an unusual way for a meningioma to spread.The Radiology Assistant : Brain Tumor . 11:22 AM On the left enhanced sagittal and coronal T1WI. On the T1WI there is a hyperintense area that shows no enhancement (i.Systematic Approach 10/31/13. Sella/suprasellar On the left is a list of common sellar and suprasellar tumors. On the coronal images we see the enhancement extending through the foramen ovale to the right of the cavernous sinus. The most striking finding is the black clivus due to the sclerosis. The tumor is complicated by a hydrocephalus. In this region it is important to keep the possibility of an aneurysm in the differential diagnosis.e. lymphoma.nl/en/p47f86aa182b3a Page 23 of 29 . chronic infection and even a meningioma . cystic). The differential diagnosis would include: skull base metastasis. The diagnosis is a nasopharyngeal squamous cell carcinoma with intracranial extension. http://www. The differential diagnosis would include an astrocytoma and a meningioma.The Radiology Assistant : Brain Tumor . http://www.radiologyassistant. Continue with the MR images. reduction in visual acuity and visual fields and papilledema. 11:22 AM On the left NECT and enhanced CT-images of a 33-year-old female with severe headache (worse in the a.m.). The diagnosis is again a craniopharyngioma. This means it is not a macroadenoma. Notice the normal inferiorly displaced pituitary gland.nl/en/p47f86aa182b3a Page 24 of 29 .Systematic Approach 10/31/13. 11:22 AM Cerebello-pontine angle Common CP Angle Tumors are listed in the table on the left. cystic presentation of a meningioma.radiologyassistant.Systematic Approach 10/31/13. There is also some enhancement within the internal acoustic canal.The Radiology Assistant : Brain Tumor . http://www. On the left a 52-year-old male with hearing loss on the right.nl/en/p47f86aa182b3a Page 25 of 29 . Pineal region Common pineal region tumors are listed in the table on the left. but this happened to be an uncommon. Based on the images the most likely diagnosis would be a cystic schwannoma. The images show an unusual cystic mass with enhancing septations. nl/en/p47f86aa182b3a Page 26 of 29 . 11:22 AM On the left a tumor located in the pineal region.The Radiology Assistant : Brain Tumor . On the left are typical images of a ruptured pineal region dermoid. http://www. Based on these images the differential diagnosis would include: Meningioma Pineocytoma Germ Cell Tumor This happened to be a meningioma.Systematic Approach 10/31/13.radiologyassistant. The Radiology Assistant : Brain Tumor . There is a tumor located in the pineal region. http://www. Intraventricular Common intraventricular Tumors are listed in the table on the left.radiologyassistant. this is most likely a germinoma. Based on the age of the patient. The tumor contains calcifications. There is homogeneous enhancement.Systematic Approach 10/31/13. 11:22 AM On the left images of a 12 y/o male with upward gaze paralysis. the location and the tumor characteristics. which is common for a tumor in the pineal region (discussed above).nl/en/p47f86aa182b3a Page 27 of 29 . radiologyassistant. followed by hemangioblastomas.Systematic Approach 10/31/13. ependymomas and brainstem gliomas with a dorsal exophytic component. The diagnosis is a giant cell astrocytoma. The tumor contains calcifications.nl/en/p47f86aa182b3a Page 28 of 29 . choroid plexus papillomas and dermoid and epidermoid cysts. Astrocytomas are the most common followed by medulloblastomas (or PNET-MB). http://www. In adults tumors in the 4th ventricle are uncommon. 4th ventricle In children tumors in the 4th ventricle are very common. Metastases are most frequently seen. 11:22 AM On the left a tumor located in the 3rd ventricle.The Radiology Assistant : Brain Tumor . Osborn Mosby 1994 http://www.The Radiology Assistant : Brain Tumor . Multiple sclerosis can present with a mass-like lesion with enhancement. 11:22 AM Tumor Mimics Many non-tumorous lesions can mimic a brain tumor.. AJR 2001. 1. also known as tumefactive multiple sclerosis. Primary Lymphoma of the Central Nervous System: Typical and Atypical CT and MR Imaging Appearances by Namik Erdag et al. Brain Lesion Locator: Differential Diagnosis by Location by James Smirniotopoulos 2. In the parasellar region one should always consider the possibility of a aneurysm.nl/en/p47f86aa182b3a Page 29 of 29 . Diagnostic Neuroradiology by Anne G. 176:1319-1326 3. Abscesses can mimic metastases.radiologyassistant. Infections and vascular lesions can also mimic a CNS tumor.Systematic Approach 10/31/13.
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