Cerebellar hemorrhage resulting in obstructive hydrocephalus and ascending transtentorial herniation
Presentation
New onset ataxia on the left. Past history of metastatic breast cancer.
Patient Data
Large left cerebellar hemisphere hemorrhage that extends across the midline and results in significant mass effect. There is almost complete effacement of the fourth ventricle, and this results in hydrocephalus. The vermis bulges into the quadrigeminal cistern, but there is no significant cerebellar tonsillar herniation.
Layering of intraventricular hemorrhage within both trigones. Periventricular high FLAIR signal due to transependymal edema.
Conclusion:
Large posterior fossa hemorrhage, centered in the left cerebellar hemisphere, results in obstructive hydrocephalus and ascending transtentorial herniation.
The patient proceeded to craniotomy and evacuation of the hemorrhage:
MACROSCOPIC DESCRIPTION: Multiple tan fragments 20x20x4mm. A1. (SD)
MICROSCOPIC DESCRIPTION: The section shows multiple fragments of blood clot. These contain solid aggregates of a densely hypercellular tumor. Tumor cells have pleomorphic round and oval vesicular nuclei, many with conspicuous nucleoli and a variable amount of pale cytoplasm. Scattered mitotic figures are noted and there are foci of tumor necrosis. Immunohistochemistry shows strong (+++) nuclear staining in >90% of tumor cells for both estrogen and progesterone receptor and strong (+++) complete membrane staining for HER-2 in >90% of tumor cells. There is also strong cytoplasmic staining in tumor cells for GCDFP, and cytokeratin CK7 as well as strong nuclear staining for GATA3. No staining for CDX2, tyrosinase or cytokeratins CK5&6 or CK20 is seen in tumor cells. The features are of metastatic undifferentiated carcinoma most consistent with an origin from breast. A small fragment of unremarkable cerebellar cortex is also included.
DIAGNOSIS: Metastatic undifferentiated carcinoma with features most consistent with an origin from breast.
Case Discussion
Cerebellar hemorrhages are uncommon, accounting for <10% of intracranial hemorrhage. They arise from poorly controlled hypertension or underlying lesions. The latter was the cause in this patient with a history of breast cancer and underlying breast metastases on histopathology.