Presentation
Drowsiness
Patient Data
Multiple supra and infra-tentorial intra-axial space-occupying lesions are noted, the supra-tentorial lesions scattered in both cerebral hemispheres, epicentered upper GW junctions, largest noted at the left frontal region. The Infra-tentorial lesions noted on both sides of the brain stem. All the lesions show heterogeneous T1 iso- to hyperintense signals, T2 hyperintense signal, areas of hemorrhagic changes (T1 hyperintense signal with blooming in SWI) and diffuse heterogeneous post contrast enhancement, apart from small necrotic changes in the large lesions. The lesions show foci of diffusion restriction.
The lesions are surrounded by variable degrees of vasogenic edema and mild mass effect notably large lesions at the right side of the pons.
There is also noted small extra-axial broad-based lesion on the left side of the anterior falx that could represent dural metastasis.
Multiple small pulmonary nodules are seen scattered in both lung lobes, mainly peripheral in location, averaging 3-6 mm suggestive of pulmonary deposits.
Case Discussion
The patient has a known primary of malignant melanoma. The lungs are the second most common site of malignant melanoma metastases after lymph node involvement, usually appearing as multiple rounded and sharply delineated lesions.
Intracranial metastatic melanoma usually appears on MRI withT1 hyperintensity of the lesion which is a relatively uncommon finding in other forms of metastatic intracranial disease. This is attributed to a decrease in T1 relaxation time caused by the presence of melanin within the melanoma. Similarly, melanotic lesions often have a reduced T2 signal.