Melanoma metastasis

Case contributed by Frank Gaillard
Diagnosis certain

Presentation

Seizure.

Patient Data

Age: 75 years
ct

Hyperdense, hemorrhagic lesion in the posterior right frontal lobe with surrounding edema. 

mri

An enhancing hemorrhagic nodule is located within the posterior right frontal lobe, abutting the grey-white matter junction of the precentral sulcus in line with the superior frontal sulcus. It is surrounded by subacute blood, both anteromedially and posterolaterally.

Surrounding it is a moderate amount of vasogenic edema, with no evidence of non-enhancing tumor, which extends both into the frontal lobe and into the pre and post-central gyrus. MR spectroscopy in the region of high T2 signal adjacent to the lesion, is normal (not shown), with no elevation of choline. Cerebral blood volume appears elevated in the enhancing nodule, although given the presence of abundant blood products is unreliable. Similarly, a degree of restricted diffusion cannot be assessed.

There is only limited localized mass effect, with no distortion of the ventricles or midline shift. The posterior fossa is unremarkable, and this is an isolated abnormality.

Conclusion: Solitary enhancing hemorrhagic lesion with surrounding hematoma and vasogenic edema has the differential diagnosis of hemorrhagic metastasis (which is favored, particularly melanoma, lung, and other classically hemorrhagic lesions such as thyroid and renal cell carcinoma) or hemorrhagic glioblastoma, which is thought substantially less likely.

Case Discussion

The patient went on to have surgery and excision. 

Histology

MICROSCOPIC DESCRIPTION: The sections show features of malignant epithelioid tumor. The tumor forms sheets with adjacent large areas of hemorrhagic necrosis. The tumor cells have enlarged pleomorphic nuclei, prominent nucleoli and moderate amounts of eosinophilic cytoplasm. No brown pigment is seen in their cytoplasm. No evidence of lymphovascular invasion is noted. The tumor cells are melan-A and SOX10 positive. The features are those of metastatic melanoma.

FINAL DIAGNOSIS: Metastatic melanoma.

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