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Five discrete intracranial intra-axial lesions are demonstrated in the parafalcine left frontal lobe (26 x 23 mm), posterior right frontal lobe (26 x 23 mm), medial left parietal lobe abutting the body of the corpus callosum (7 x 5 mm), in the right insular cortex (4 x 4 mm) and in the left cerebellar hemisphere (37 x 30 mm). Supratentorial lesions demonstrate contrast enhancement and the left frontal lesion has a cystic component. Right parietal lesion demonstrates susceptibility artefact indicating central haemorrhage. The lesions have intrinsic T1 high signal, particularly the left cerebellar lesion. Left cerebellar lesion also demonstrates intrinsic T2 high signal and central diffusion restriction.
Moderate T2/FLAIR high signal surrounds the right and left frontal lesions. Minimal T2/FLAIR high signal is seen in relation to the left cerebellar lesion. These lesions exert mass effect with effacement of the nearby sulci. There is left-sided tonsillar descent up to 3 mm. No midline shift.
Multiple (5 seen) intraaxial contrast enhancing lesions as described, the largest in the parafalcine left frontal lobe, posterior right frontal lobe and left cerebellum. The left frontal and left cerebellar lesions are haematoma of different age, but all lesions show intrinsic T1 hyperintensity. Haemorrhagic metastases or metastatic melanoma are the differential diagnosis.
The patient had a history of melanoma and went on to have a craniotomy.
Paraffin sections show fragments of unremarkable cerebellar cortex and a separate large fragment which is largely necrotic and shows recent haemorrhage. Within this fragment there are scattereed aggregates of atypical cells which have irregularly shaped vesicular nuclei with prominent nucleoli and a small amount of pale cytoplasm.
These show immunostaining for tyrosinase and melan A. No staining in these cells for cytokeratins AE1/AE3 or CAM5.2 is seen. The features are strongly suggestive of metastatic malignant melanoma.
Metastatic malignant melanoma.