Presentation
Right sided weakness.
Patient Data
Three intracranial lesions are demonstrated all surrounded by vasogenic edema, and all demonstrating signal loss and intrinsic high T1 signal consistent with hemorrhagic change. The left frontal lesion exerts a significant localized mass effect, with 8 mm of midline shift.
Conclusion: Hemorrhagic metastatic disease; primaries to consider are melanoma, choriocarcinoma, thyroid, renal cell carcinoma as well as breast and lung cancer.
On CT (not shown) I note the presence of a large mediastinal mass without obvious breast, thyroid, renal or pelvic masses. As such melanoma is favored.
Case Discussion
The patient went on to have surgery.
Histology
Paraffin sections show fragments of a densely hypercellular tumor. Tumor cells have markedly pleomorphic round and oval nuclei with vesicular chromatin, prominent nucleoli and a variable amount of eosinophilic cytoplasm. The cytoplasm of scattered cells contains finely granular black-brown pigment. Frequent mitotic figures are identified and there is extensive tumor necrosis. Tumor cells show positive immunostaining for tyrosinase.
FINAL DIAGNOSIS: Metastatic malignant melanoma.