Acute cerebral hemorrhage mimicking glioblastoma on intraoperative magnetic resonance imaging: A case report

Intraoperative magnetic resonance imaging (iMRI) is important in neurosurgical practice, especially for glioma surgery. However, the well-reported possibility to mistake lesions for brain tumors (tumor mimics) with MRI also exists for iMRI. Here, we first report a case of glioblastoma with acute cerebral hemorrhage that mimicked a newly emerged brain tumor on iMRI. A 53-year-old man underwent a second surgery for recurrent glioblastoma. Intraoperatively, iMRI revealed a new, enhanced lesion near the resected area that was absent on preoperative MRI and difficult to differentiate from newly emerged tumors. Here, a recent preoperative MRI was helpful and the new lesion was actually a hematoma. Neurosurgeons must understand that, as acute intracerebral hemorrhaging can mimic brain tumors on iMRI, preoperative MRI should be conducted just before surgery to place iMRI findings in proper context and avoid unnecessary resections

Sclerosing meningioma with a large peritumoral cyst: Case report

Meningioma morphology is diverse. Although unlisted in the WHO classification, sclerosing meningioma is a rare variation featuring an extremely low signal intensity on MRI T2-weighted imaging. About 50 cases of sclerosing meningiomas, including spinal tumors, have been reported; however, cases with an accompanying large peritumoral cyst remain unreported. Here, we first report a rare case of sclerosing meningioma with a large peritumoral cyst and review relevant literature

H3 K27-altered diffuse midline glioma in adults arising from atypical regions: Two case reports and literature review

Diffuse midline glioma (DMG), H3 K27-altered, is a newly defined “pediatric-type,” diffuse, high-grade glioma under current WHO classifications (updated in 2021). An essential diagnostic criteria of DMG is its occurrence in the midline structures; most intracranial DMG occurs in the brainstem or thalamus but can also occur in other midline structures. We experienced 2 adult cases of intracranial DMGs in areas other than the brainstem and thalamus that were initially difficult to diagnose. Case 1 was a 49-year-old man with extensive T2 high-signal lesions in the bilateral frontal lobes and corpus callosum on brain MRI. A Gd-based contrast medium partially enhanced the lesion and showed marked diffusion restriction, mimicking malignant lymphoma. Case 2 was a 24-year-old man who presented with paroxysmal olfactory abnormalities. The tumor extended mainly to the right temporal lobe, the right basal forebrain, and the bilateral hypothalamus, showing a T2/FLAIR mismatch sign suggestive of IDH-mutant astrocytoma without 1p/19q co-deletion. After a biopsy, both cases were properly diagnosed as DMG, H3 K27-altered (K27M-mutant). Diagnosing adult cases involving atypical midline structures is sometimes challenging before surgery; we discuss this phenomenon with both case details and a literature review

Atypical chronological changes on neuroimaging in the epidermoid in the frontal lobe with intracystic hemorrhage and tumor growth: Case report

Intracranial epidermoids are rare lesions accounting for 0.2%-1.8% of all intracranial tumors. They commonly develop in the cerebellopontine angle and the parasellar region and can appear with atypical neuroimaging features due to intracystic hemorrhages which complicate diagnosis. The authors present a case of a 62-year-old woman with a frontal epidermoid cyst with a hemorrhage and tumor growth. A series of atypical radiological findings showed gradual changes in the lesion appearance that were confirmed with surgery and histopathology. To avoid surgical complications such as chemical meningitis, it is important to remember that epidermoid cysts occasionally bleed, leading to atypical MRI and/or CT findings and diagnostic difficulties. Development of epidermoid cysts in atypical locations in the brain may result in challenges to accurate diagnosis. Keywords: Epidermoid cyst, Intracystic hemorrhage, Atypical radiological finding

Frontal sinus giant osteoma with radiologically unusual component suggesting blood supply: A case report

Osteoma is a common, slow growing bone tumor, and often affects the paranasal sinus. Typically, it shows a very hyperdense osseous lesion on computed tomography (CT) scan and low-intensity change on T2-weighted image on magnetic resonance imaging (MRI). No report has mentioned osteomas in blood supply on MRI. A 57-year-old male patient presented with a prolonged declined activity and a gigantic osseous tumor that originated from the frontal sinus, which markedly compressed the bilateral frontal lobe. MRI revealed a slightly enhanced front basal part of the tumor by gadolinium, with blood supply from ethmoidal arteries. The patient underwent surgery, and the diagnosis of osteoma was made based on histological findings. We reported a case of giant osteoma originating from the frontal sinus with unusual blood supply on 4-dimensional MR angiography

Significance of perilesional T1 hyperintense areas in the differential diagnosis of primary adult-type diffuse glioma: A case report

Perilesional T1 hyperintensity on magnetic resonance imaging (MRI) of intra-axial brain masses is an unusual feature of the perilesional area, characteristic of cavernous malformations (CMs) and metastatic brain tumors (METs). Here, we report a case of primary diffuse glioma with a perilesional T1 hyperintense area (HIA) on MRI. A 61-year-old woman with transient aphasia visited our hospital. Radiological examination revealed an intra-axial mass with acute/subacute hemorrhaging and calcification in the left frontal lobe. It was presumed to be a CM because of the perilesional T1 HIA. Gross total resection of the tumor was performed, and the pathological diagnosis was anaplastic oligodendroglioma, not otherwise specified by World Health Organization 2016 classification. Histopathological findings in the perilesional T1 HIA indicated hemorrhage involvement in the surrounding white matter. No recurrence appeared after radio-chemotherapy. Perilesional T1 HIAs, characteristic of CMs and METs, are also seen in primary diffuse gliomas. Therefore, caution should be taken when using this sign for the differential diagnosis of intracranial masses