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Images courtesy of Omaditya Khanna, MD, and Christopher J Farrell, MD.

10 Brain Lesions to Recognize

Omaditya Khanna, MD; George M Ghobrial, MD; Christopher J Farrell, MD | October 25, 2021 | Contributor Information

A 26-year-old male presents with a 3-week history of progressively worsening confusion, agitation, and decreased sensorium. Imaging shows an enhancing mass along the septum pellucidum, extending into the medial aspect of the lateral ventricles This causes obstructive hydrocephalus, with trapping of the temporal horn of the right lateral ventricle. The sagittal image on the right shows a concomitant enhancing lesion in the suprasellar space (yellow arrow).

Tandem lesions in the periventricular region and suprasellar space suggest central nervous system (CNS) germinomas, although other pathologies, such as gliomas and CNS lymphomas, are in the differential. CNS germinomas make up about 3% of all pediatric tumors.[1] While most are diagnosed in childhood, some may be identified later, as in this patient.

Images courtesy of George M Ghobrial, MD, and Christopher J Farrell, MD.

10 Brain Lesions to Recognize

Omaditya Khanna, MD; George M Ghobrial, MD; Christopher J Farrell, MD | October 25, 2021 | Contributor Information

T1-weighted magnetic resonance imaging (MRI) scans of a meningioma, showing axial (left) and coronal (right) views.

A 40-year-old man sustains a head injury in an accidental fall, without loss of consciousness. Computed tomography (CT) scanning of the brain is performed, demonstrating a suspicious mass. The patient is then referred for magnetic resonance imaging (MRI) and office evaluation by a neurosurgeon. T1-weighted MRI with gadolinium contrast demonstrates a dural-based lesion of the left convexity that measures 4.5 × 4 cm and shows homogeneous, contrast-based enhancement.

Because the lesion is large and the patient is relatively young, a craniotomy is performed, with gross total resection of the lesion. The pathology is consistent with a World Health Organization (WHO) grade II meningioma.

Image courtesy of George M Ghobrial, MD, and Christopher J Farrell, MD.

10 Brain Lesions to Recognize

Omaditya Khanna, MD; George M Ghobrial, MD; Christopher J Farrell, MD | October 25, 2021 | Contributor Information

The above image shows the cavity after resection of the previously discussed meningioma, with the compressed underlying brain (dashed arrow) and dural margins (solid arrow) visible.

Meningiomas are the most frequently encountered primary intracranial tumor in clinical practice. Based on the WHO grading system, they are classified as follows:

  • Grade I meningiomas, which account for 80-85% of meningiomas, are low-grade, benign neoplasms that have high rates of progression-free survival and low overall mortality[2,3,4]
  • Grade II (atypical) and grade III (anaplastic) meningiomas are associated with higher rates of recurrence despite maximal surgical and radiation treatment
Image courtesy of George M Ghobrial, MD, and Christopher J Farrell, MD.

10 Brain Lesions to Recognize

Omaditya Khanna, MD; George M Ghobrial, MD; Christopher J Farrell, MD | October 25, 2021 | Contributor Information

A 45-year-old male presents with his first seizure, and a brain MRI reveals an intra-axial lesion within the temporo-occipital lobe, without any evidence of contrast enhancement. This is consistent with a low-grade (WHO grade II) glioma, a highly infiltrative tumor that may progress to a malignant (WHO grade III/IV) lesion over time. Patients are typically stratified as high risk for recurrence if they are older than 40 years and if only a less-than-total resection of the radiographic abnormality can be performed. In low-risk patients, a survival benefit has not been demonstrated for adjuvant radiation therapy, chemotherapy, or both, after gross total resection, and serial observation with MRI remains reasonable.[5]

Images courtesy of George M Ghobrial, MD, and Christopher J Farrell, MD.

10 Brain Lesions to Recognize

Omaditya Khanna, MD; George M Ghobrial, MD; Christopher J Farrell, MD | October 25, 2021 | Contributor Information

A 55-year-old man presents with progressive confusion and left-sided hemiparesis. MRI reveals a cystic mass with ringlike peripheral enhancement and slight extension through the corpus callosum (solid arrow). The fluid-attenuated inversion recovery (FLAIR) sequence shows extensive vasogenic edema (dotted arrow) with midline shift. A craniotomy is performed for resection of a glioblastoma (a WHO grade IV glioma).[6]

The median survival time in patients with glioblastomas, the most common primary brain tumors in adults, is a poor 15 months, with the 5-year survival rate being less than 2%. However, several factors may contribute to better outcomes, such as isocitrate dehydrogenase 1 (IDH-1) mutation status, O6-methylguanine-DNA-methyltransferase (MGMT) methylation, and tumor location.[7,8,9,10]

Image courtesy of George M Ghobrial, MD, and Christopher J Farrell, MD.

10 Brain Lesions to Recognize

Omaditya Khanna, MD; George M Ghobrial, MD; Christopher J Farrell, MD | October 25, 2021 | Contributor Information

A 33-year-old female presents with progressive headaches and an unquenchable thirst despite copious water intake. The above MRI demonstrates a craniopharyngioma, with the suprasellar cystic lesion showing peripheral enhancement. Craniopharyngiomas are benign (WHO grade I) tumors that occur in the sellar and suprasellar regions. Arising from embryonic epithelium derived from the Rathke pouch, they can appear with cystic or calcified components.[11] They often cause visual deficits, owing to optic chiasm compression, and endocrine abnormalities (eg, diabetes insipidus), due to disruption of the hypothalamic-pituitary axis. Each of the two subtypes of craniopharyngiomas tends to target a different group, with the adamantinomatous subtype most often being found in pediatric patients, and the papillary subtype usually developing in adults.[12]

Images courtesy of George M Ghobrial, MD, and Christopher J Farrell, MD.

10 Brain Lesions to Recognize

Omaditya Khanna, MD; George M Ghobrial, MD; Christopher J Farrell, MD | October 25, 2021 | Contributor Information

A 65-year-old woman presents with a 2-month history of progressive headaches and right-arm numbness. MRI reveals an enhancing brain mass in the left parietal lobe with surrounding vasogenic edema. CT scanning of the chest reveals a spiculated lung mass.

Brain metastases in patients with lung cancer are common, and resection of a lone brain metastasis in patients with non–small cell lung cancer (NSCLC) has been shown to increase survival and improve quality of life as compared with whole-brain radiotherapy (WBRT) by itself.[13] Stereotactic radiosurgery (SRS) in combination with WBRT has demonstrated a similar survival benefit for NSCLC. Brain metastases due to SCLC are highly radiosensitive, and surgical resection has not been found to affect survival compared with radiotherapy alone.[14]

Image courtesy of George M Ghobrial, MD, and Christopher J Farrell, MD.

10 Brain Lesions to Recognize

Omaditya Khanna, MD; George M Ghobrial, MD; Christopher J Farrell, MD | October 25, 2021 | Contributor Information

A 17-year-old male presents with progressive headaches located in the back of the head. The above image shows a left occipital cavernous malformation close to the brain's surface, demonstrating the lesion's characteristic "popcorn" appearance. Histologically, cavernous malformations are low-pressure vascular malformations consisting of multiple dilated, thin-walled capillaries, with rates of hemorrhage ranging from 1-4% per year, cumulatively over a lifetime.[15] Cavernous malformations are angiographically occult and are often discovered incidentally, though they may present with headaches, seizures, or focal neurologic deficits.[16]

Images courtesy of George M Ghobrial, MD, and Christopher J Farrell, MD.

10 Brain Lesions to Recognize

Omaditya Khanna, MD; George M Ghobrial, MD; Christopher J Farrell, MD | October 25, 2021 | Contributor Information

A 60-year-old man presents with a 2-year history of progressive, right-sided hearing loss. MRI (left: axial T1, post contrast; right: coronal T1, post contrast) demonstrates a homogeneously enhancing, 1.5-cm brain mass within the cerebellopontine angle (CPA) consistent with a vestibular schwannoma.[17] Also referred to as acoustic neuromas, vestibular schwannomas are benign tumors that develop from the vestibulocochlear nerve (cranial nerve VIII). They typically present with sensorineural hearing loss, tinnitus, and disequilibrium. Although most vestibular schwannomas occur sporadically, bilateral tumors are the hallmark of the inherited syndrome neurofibromatosis type 2 (NF-2). Vestibular schwannomas may be treated via surgical resection, radiosurgery, or both, depending on the tumor's size, location, and presenting symptoms.[18]

Images courtesy of George M Ghobrial, MD, and Christopher J Farrell, MD.

10 Brain Lesions to Recognize

Omaditya Khanna, MD; George M Ghobrial, MD; Christopher J Farrell, MD | October 25, 2021 | Contributor Information

A 52-year-old woman presents with a history of progressive confusion over 2 months, followed by rapid neurologic deterioration. CT scanning (left) shows a hyperdense mass in the third ventricle, with obstructive hydrocephalus. Subsequent MRI demonstrates multifocal areas of enhancement (middle, solid arrows) in the periventricular area and within the third ventricle, blocking the sylvian aqueduct (right, dotted arrow). The imaging is most consistent with primary CNS lymphoma.

Image courtesy of George M Ghobrial, MD, and Christopher J Farrell, MD.

10 Brain Lesions to Recognize

Omaditya Khanna, MD; George M Ghobrial, MD; Christopher J Farrell, MD | October 25, 2021 | Contributor Information

Primary CNS lymphoma is an aggressive form of non-Hodgkin lymphoma. The majority of primary CNS lymphomas are diffuse large B-cell lymphomas and may affect the brain, spinal cord, eyes, meninges, and cranial nerves. Currently, chemotherapy regimens involving high-dose IV methotrexate are considered the standard of care and are capable of achieving high rates of initial response.[19]

Images courtesy of George M Ghobrial, MD, and Christopher J Farrell, MD.

10 Brain Lesions to Recognize

Omaditya Khanna, MD; George M Ghobrial, MD; Christopher J Farrell, MD | October 25, 2021 | Contributor Information

A 30-year-old woman presents with worsening headaches, nausea, and difficulty walking. MRI reveals a cystic lesion (left) within the CPA without restricted diffusion (right), findings consistent with an arachnoid cyst. Usually benign, arachnoid cysts are thought to arise from abnormal arachnoid layer formation during embryogenesis. In rare cases, however, abnormal CSF flow can produce an arachnoid cyst and cause it to enlarge, compressing brainstem structures. Arachnoid cysts may occur anywhere in the brain or spine; the most common location is the middle fossa (>50%), followed by the posterior fossa. CPA arachnoid cysts usually present with ataxia followed by headaches.[20]

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