Radiology Quiz 21171 | Radiopaedia.org

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Which primary tumours are most likely to metastasise to choroid plexus?

In adults, tumours most likely to metastasize to the choroid plexus are renal cell carcinoma and lung carcinoma. Other tumours with documented spread to the choroid plexus include colon cancer, gastric adenocarcinoma, breast carcinoma, thyroid carcinoma, transitional cell carcinoma, malignant melanoma and lymphoma. When seen in the paediatric population, metastates to the choroid plexus have been reported to arise from Wilms tumour, neuroblastoma or retinoblastoma.

Question 2

What two routes of spread are most common in tumours metastasising to the choroid plexus?

Show Answer

Tumour spread to the choroid plexus may occur via a haematogenous route via the anterior or posterior choroidal arteries or through CSF seeding.

This patient had a prior history of renal cell carcinoma and nephrectomy 2 years previously without evidence of metastatic disease. He went on to have a craniotomy and resection of the mass, at which time it was still difficult to identify the site of origin as both the choroid plexus and adjacent brain were involved.

Histology

MICROSCOPIC DESCRIPTION: Sections show a moderately cellular tumour surrounded by pools of blood and only a small amount of brain parenchyma. The tumour comprises clusters of cells intersected by a rich vascular network. The tumour cells have ovoid mildly pleomorphic nuclei, inconspicuous nucleoli and moderate amount of granular to clear eosinophilic cytoplasm. Some cells show well defined cytoplasmic outlines. Mitotic activity is inconspicuous.

The tumour cells are CD10 and Vimentin positive but Inhibin, S-100, CK7, CK20, TTF-1, CDX-2 negative. The morphological and immunohistochemical features are of a metastatic renal cell carcinoma.

FINAL DIAGNOSIS: Metastatic renal cell carcinoma.