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

Abstract

Hyperintense perilesional edema in brain masses on T1-weighted images (T1WI) is an unusual radiological finding. We report three cases showing this particular type of edema, one representing cerebral hemorrhagic cavernous malformation (CCM, cavernoma) and the other two, metastases of melanoma. The association between this sign and cavernoma was recently recognized. On the other hand, in melanotic lesions, the relationship with T1WI-hyperintense perilesional edema has not yet been described. Despite being an infrequent sign, it can considerably narrow the differential diagnosis, which gives it a high value for clinical practice. Moreover, given the high prevalence of the entities that manifest this imaging feature, it can be occasionally noticed.

Keywords: Cerebral cavernous malformation; cavernoma; hyperintense edema on T1; melanoma.

Figure 1.

NE-CT shows a hyperdense nodular lesion (arrow in (a)), surrounded by a dense area (star in (a)), involving the subcortical region of the right precentral gyrus and right superior and middle frontal gyri. On MR, the lesion is hypointense on both T1WI and T2WI (arrow in b, d), has high susceptibility effect on SWI (thin arrow in (f)), and it is surrounded by a hyperintense area on T1WI and T2WI suggestive of subacute hematoma (star in (b) and (d)) and more peripherally, by a thin hypointense hemosiderin ring best visualized on SWI (thick arrow in (f)). Hyperintense edema on T1WI is depicted (arrowheads in (b)). No contrast-enhancement is noticed (c). NE-CT: nonenhanced computed tomography; NE-T1: nonenhanced T1-weighted imaging; CE-T1 contrast-enhanced T1-weighted imaging; MR: magnetic resonance; SWI: susceptibility-weighted imaging.

Figure 2.

NE-CT demonstrates a hyperdense focal lesion (arrow in (a)), non-enhancing and surrounded by edema (b) located in the cortico-subcortical junction of the left frontal lobe. On MR it is heterogeneous and does not present contrast enhancement ((c)–(f)). Remarkably, hyperintense perilesional edema on T1WI can be seen (arrowheads in (c)). NE-CT: nonenhanced computed tomography; CE-CT: contrast-enhanced computed tomography; MR: magnetic resonance; NE-T1: nonenhanced T1-weighted imaging; CE-T1: contrast-enhanced T1-weighted imaging.

Figure 3.

Initial, preoperative MR showing a left frontal lesion, hypointense on T1WI (a) and presenting contrast enhancement (arrowhead in b). Follow-up MR, three months after surgery ((c), (d)), shows linear enhancement in the periphery of the excised area (arrowhead in (d)) and lack of edema. Next MR, six months after surgery ((e)–(i)), demonstrates recurrence with significant contrast enhancement ((f), (h)). Notably, hyperintense edema on T1WI is now present (arrow in (e)–(h)). T2WI demonstrates greater extension of the edema (i). T1WI: T1-weighted imaging; NE-T1: nonenhanced T1-weighted imaging; CE-T1 contrast-enhanced T1-weighted imaging; MR: magnetic resonance.