Board Review 3 – Case 11

Posted on May 22, 2020 by Brent Weinberg, MD

Board Review 3 – Case 11

Neuroradiology board review. This lecture is geared towards the ABR core exam for residents, but it would be useful for review for the ABR certifying exam or certificate of added qualification (CAQ) exam for neuroradiology.

More description and the answer (spoiler!) are seen below the video.

This case shows a nodular lesion with calcification in the right frontal lobe. There is surrounding vasogenic edema with sparing of the cortex. CT images from higher in the brain show other areas of calcification at the gray-white junction thoughout the brain.

MR confirms these findings. There is an area of right frontal edema with a rounded enhancing structure at the gray-white junction. There is a differential diagnosis for this finding which includes infection and metastatic disease.

The diagnosis is: neurocysticercosis

Neurocysticercosis is a parasitic infection with a dual life cycle that goes through pigs and humans. When eggs excreted in human feces are ingested, it can affect the CNS. It is the most common cause of acquired seizure in endemic areas.

The treatment is anti-parasitic agents, specifically albendazole.

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Board Review 3 – Case 10

Posted on April 10, 2020April 5, 2020 by Brent Weinberg, MD

Board Review 3 – Case 10

More description and the answer (spoiler!) are seen below the video.

This case shows a right posterior frontal tumor. There is mild mass effect with infiltrative T2 hyperintensity. On gradient imaging, there is some evidence of internal blood products or hemorrhage. Post-contrast imaging shows a multilobular and enhancing mass with irregular margins and central necrosis.

The diagnosis is: glioblastoma (GBM)

Glioblastoma, formerly known as glioblastoma multiforme, is a grade 4 primary astrocytoma and the most common primary glioma. They have extremely poor prognosis and are characterized by irregular and necrotic enhancing masses. The surrounding T2 abnormality is a result of vasogenic edema and infiltrative tumor.

With any solitary enhancing parenchymal mass, there is a differential diagnosis that should be considered, including:

glioblastoma
metastasis
lymphoma
abscess (should have bright internal DWI)
other infections

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Board Review 3 – Case 9

Posted on April 8, 2020April 5, 2020 by Brent Weinberg, MD

Board Review 3 – Case 9

More description and the answer (spoiler!) are seen below the video.

This case shows a mass in the left cerebellopontine angle (CP angle). It is predominantly outside of the internal auditory canal (IAC), although there is extension into the canal. It is relatively homogeneous with avid post-contrast enhancement.

The diagnosis is: meningioma

Meningiomas are the most common brain tumors (although they are extra-axial). They often have a cerebrospinal fluid (CSF) cleft around them which allow you to determine that they are extra-axial. They can calcify and cause adjacent hyperostosis of the bone.

A useful approach to CP angle masses is to first consider whether it is cystic or solid. Solid masses enhance on post-contrast imaging. If they are centered in the IAC and cause expansion, it is most likely a schwannoma. If it does not cause expansion or looks centered outside the IAC, think about meningioma.

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Board Review 3 – Case 8

Posted on April 6, 2020April 5, 2020 by Brent Weinberg, MD

Board Review 3 – Case 8

More description and the answer (spoiler!) are seen below the video.

This case shows a teenager with T2 hyperintense mass in the left posterior fossa resulting in mass effect on the 4th ventricle. On post-contrast imaging there is scattered hazy enhancement throughout portions of the mass.

The diagnosis is: pilocytic astrocytoma

Pilocytic astrocytomas are the most common brain tumors in children. They most commonly occur in the posterior fossa and are often characterized by a cystic mass with a nodular enhancing area. They are relatively benign tumors with a good 10 year survival.

When you encounter a cyst with a nodule, there is a relatively short differential diagnosis which includes:

Pilocytic astrocytoma
Ganglioglioma
Hemangioblastoma (has blood vessels/flow voids)
Plemomorphic xanthoastrocytoma – PXA

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Board Review 3 – Case 7

Posted on April 4, 2020April 5, 2020 by Brent Weinberg, MD

Board Review 3 – Case 7

More description and the answer (spoiler!) are seen below the video.

This case shows expansion of the sella on a noncontrast CT, suggesting a long-standing mass. The MRI shows an underlying mass which has areas of hypointensity on T2 and intrinsic hyperintensity on T1 weighted imaging. There is minimal if any enhancement on post-contrast imaging.

The diagnosis is: pituitary adenoma (with hemorrhage)

Pituitary adenomas are common masses of the sella, with about half being non-functional and half hormone secreting. The most common hormone secreted is prolactin, followed by growth hormone. Adenomas can hemorrhage, causing variable imaging appearance.

The primary differential consideration is Rathke cleft cyst, which is more commonly midline, less likely to have blood products and septations, and may have a characteristic peripheral nodule. You can read more about differentiating adenomas and Rathke cleft cysts here.

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Board Review 3 – Case 6

Posted on April 2, 2020April 5, 2020 by Brent Weinberg, MD

Board Review 3 – Case 6

More description and the answer (spoiler!) are seen below the video.

This case shows a young adult who underwent precocious puberty. There is an expansile, non-enhancing mass in the region of the hypothalamus/tuber cinereum.

The diagnosis is: hypothalamic hamartoma

Hypothalamic hamartomas are disorderly (hamartomatous) collections of neurons in the hypothalamic/suprasellar region. They most commonly occur just behind the optic chiasm and pitutitary infundibulum. Many times, they will present with unusual symptoms like early puberty (most common) or seizure (even with uncommon seizures like laughing “gelastic” seizures or crying seizure).

The differential diagnosis for masses in this region include astrocytoma, craniopharyngioma, and germinoma. The most common overall mass in this region is craniopharygioma, but these commonly enhance avidly, have a mix of solid and cystic regions, and can calcify.

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Board Review 3 – Case 5

Posted on March 31, 2020March 30, 2020 by Brent Weinberg, MD

Board Review 3 – Case 5

More description and the answer (spoiler!) are seen below the video.

This case shows multiple hemorrhagic and hyperdense masses on a CT. They are predominantly supratentorial, have some edema, and are numerous.

On MRI, the regions have areas of susceptibility (dark T2 signal on GRE), surrounding edema, and enhance avidly.

The diagnosis is: metastatic disease

Intracranial metastases are extremely common and should be considered any time there are multiple masses (although 50% may be solitary). They can have hemorrhage and almost always enhance on post-contrast imaging. The most common locations are supratentorial and at the gray white junction because of the high vascularity there.

Metastases are treated with surgery or radiation. If there is oligometastatic disease (less than 10-20 lesions), stereotactic radiosurgery may be performed. Numerous lesions or leptomeningeal disease can require whole brain radiotherapy.

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Board Review 3 – Case 4

Posted on March 29, 2020March 25, 2020 by Brent Weinberg, MD

Board Review 3 – Case 4

More description and the answer (spoiler!) are seen below the video.

This case shows an expansile extra-axial mass along the left frontal and parietal calvarium. On CT, it is hyperdense to the adjacent brain and it is causing mass effect and edema in the surrounding brain.On MRI, it is relatively T2 homogenous, appears to be arising outside the brain, and enhances homogenously and avidly.

The diagnosis is: meningioma

Aggressive extra-axial lesions, particularly those causing cortical destruction, have a differential including metastasis, meningioma, lymphoma, and myeloma. You may not be able to differentiate these by imaging.

Meningiomas are the most common brain tumors and most common extra-axial masses. They range in aggressiveness from WHO grade 1 (typical), grade 2 (atypical), and grade 3 (anaplastic), which is determined primarily on histologic features and not imaging criteria. Grade 1 tumors are treated with resection while grades 2 and 3 receive resection followed by radiation therapy.

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Board Review 3 – Case 3

Posted on March 27, 2020March 25, 2020 by Brent Weinberg, MD

Board Review 3 – Case 3

More description and the answer (spoiler!) are seen below the video.

This case shows a nodular mass along the right frontal calvarium in a patient with pain. It is T2 hyperintense, T1 hypointense, and enhances avidly.

The diagnosis is: skull metastasis

Any mass in the calvarium that has associated osseous destruction is concerning. Benign masses often contain fat (are T1 hyperintense and suppress on T2 fat-saturated imaging) and rarely destroy the cortex. Pain, as was experienced by the patient in this case, is also a concerning feature.

Any patient with a concerning calvarial mass but no history of malignancy should probably be evaluated for metastatic disease. While the evaluation may vary by institution, it will most commonly consist of a whole body PET/CT or CT of the chest, abdomen, and pelvis.

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Board Review 3 – Case 2

Posted on March 25, 2020 by Brent Weinberg, MD

Board Review 3 – Case 2

More description and the answer (spoiler!) are seen below the video.

This case shows a nodular multifocal mass along the walls of the ventricles. It is relatively low intensity on T2, hyperintense on DWI, and enhances avidly with a nodular solid pattern.

The diagnosis is: CNS lymphoma

Primary CNS lymphoma is a B-cell malignancy with relatively low incidence but overall poor outcomes. It is more common in immunocompromised or HIV patients. The most common locations are in periventricular white matter, the basal ganglia, and the corpus callosum. Solid nodular enhancement, T2 hypointensity, and low ADC values are characteristic. In fact, lower ADC values are associated with a poorer prognosis.

HIV and immunocompromised patients are more likely to have variable enhancement patterns, such as rim enhancement with central necrosis.

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