Hyperintense perilesional edema in the brain on T1-weighted images: Cavernous malformation or metastatic melanoma? Three case reports and literature review

Giant Intracranial Cavernous Malformations: A Review on Magnetic Resonance Imaging Characteristics

Background  Intracranial cavernous malformations (CMs), commonly known as cavernomas or cavernous angiomas, are low-flow, well-circumscribed vascular lesions composed of sinusoidal spaces lined by a single layer of endothelium and separated by a collagenous matrix without elastin, smooth muscle, or other vascular wall elements. A diameter greater than 3 cm for a CM is unlikely. These lesions may have atypical appearances on magnetic resonance imaging (MRI). MRI with advanced techniques such as a susceptibility-weighted image or T2-gradient echo, a diffusion-weighted image and corresponding apparent diffusion coefficient map, and diffusion tensor tractography have revolutionized the diagnostic approach to these lesions. Materials and Method  The present study reviews the etiopathogenesis, clinical manifestations, MRI strategy, and MRI appearances of the CMs, with a few examples of the giant CMs from our archive. Results  Intracranial giant CMs may have unexpected locations, sizes, numbers, and varied imaging appearances due to repeated hemorrhages, unusual enhancement patterns, intense perifocal edema, and unusual associations, making the differential diagnosis difficult. Conclusion  Familiarity with the MRI appearances of the giant intracranial CMs and the differential diagnosis improves diagnostic accuracy and patient management.

Hyperintense Perilesional Edema on T1-Weighted Imaging in Cavernoma: A Case Report

Cavernoma, also called a cavernous malformation, is a vascular malformation that happens during development. It tends to look like a berry-shaped lesion. In cerebral hemorrhagic cavernous malformations (cavernoma), T1-weighted imaging that shows hyperintense perilesional edema in brain masses is an unusual radiological finding. This sign's association with cavernoma is gaining prominence. We present the case of a 35-year-old female patient without significant medical history who reported a seven-day history of left-side weakness that began in the upper limb, progressed to the lower limb, and was associated with nausea. The non-contrast T1- T1-weighted images displayed a gradient of hyperintense content of the lesion with surrounding relatively hyperintense perilesional edema. The patient consequently underwent surgery to evacuate the hematoma and excise the lesion, which went uneventfully.

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.

Distinguishing mimics from true hemorrhagic cavernous malformations

Cavernous malformations (CM) are angiographically occult vascular malformations. CM appear as discrete, small lesions with mixed-signal characteristics on T2 reflecting the underlying pathology. However, the appearance is not pathognomonic. Distinguishing true CM from hemorrhagic tumors can be difficult. We report 5 cases of tumors mimicking CMs. We compared clinical, initial radiologic features, and MRI evolution between 5 tumor mimics and 51 true hemorrhagic, sporadic, brain CM. Compared to true CM, mimic patients were older (47.0 vs. 38.3 years; p = 0.076) and more likely to have a history of primary neoplasm (60% vs 12%; p = 0.0267). Radiologically, the CM mimics demonstrated a higher likelihood of lesion enhancement on the initial diagnostic MRI (60% vs. 16.7%%; p = 0.0609). On follow-up MRI (<1 year after baseline), CM mimics typically had persistent edema (100.0% vs. 6.25%, p = 0.0003) and demonstrated mixed density on ADC (100% vs. 32.1%; p = 0.0199) as well as increased likelihood of enhancement (100% vs 25.8, p = 0.0852). CM mimics were less likely to evolve to Type 2 or 3 lesions (25.0% vs. 84.4%, p = 0.0278). Clinical and radiologic factors may distinguish tumor metastases from true hemorrhagic CM. CM mimics should be suspected in older patients with a history of neoplasm and contrast enhancement on initial MRI. A repeat MRI within 90 days post-initial hemorrhage should be considered to confirm CM diagnosis. Persistent edema without rebleed, lesion enhancement, mixed signal on apparent diffusion co-efficient, and persistence of a Type 1 lesion should raise suspicion of a metastatic tumor.