choroid plexus metastases

Metastases to the choroid plexus from extracranial tumors are rare, but nonetheless should be included in the differential diagnosis of an intraventricular mass. They are most commonly found within the lateral ventricles, presumably because a large proportion of the choroid plexus is located there.

Epidemiology

Choroid plexus metastases account for <5% of intracranial metastases in autopsy series, and <1% of clinically evident cerebral metastases . They are seen most commonly in adults, although have also been found in children with extracranial childhood tumors.

Pathology

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

Tumors most likely to metastasize to the choroid plexus are renal cell carcinoma and lung cancer. Other tumors with documented spread to the choroid plexus include colon, gastric, breast, thyroid, and bladder cancers, melanoma, lymphoma, and  carcinoma of the esophagus .

When seen in the pediatric population, metastases to the choroid plexus have been reported to arise from Wilms tumor, neuroblastoma and retinoblastoma.

Radiographic findings

Choroid plexus metastases may be seen on CT or MRI as either a solitary lesion, or as a component of disseminated intracranial metastatic disease. Reported complications which may be found on imaging include hydrocephalus and hemorrhage from an intraventricular metastasis .

CT

Imaging appearance is variable. The lesion may be hypo or isodense on non-enhanced CT, and may demonstrate moderate or marked enhancement, more commonly homogeneous .

MRI

MRI is more sensitive than CT in the detection of small choroid plexus lesions.

With larger lesions, there may be peritumoural edema or invasion into adjacent brain parenchyma.

Treatment and prognosis

These lesions may be amenable to surgical resection. Prognosis is variable and depends on the type and stage of the primary tumor, and extent of metastatic dissemination.

Differential diagnosis

The differential diagnosis is that of other intraventricular masses that may arise in the relevant age group. In an adult patient, consider:

• intraventricular meningioma: particularly at the trigone of a lateral ventricle
• colloid cyst: when at the foramen of Monro 
• central neurocytoma 
• subependymoma: particularly if there is poor enhancement

See also

• intraventricular masses (differential)
• intraventricular masses - an approach

Siehe auch:

• intraventrikuläre Neoplasien und Läsionen
• intraventrikuläre Blutung
• intraventrikuläres Meningeom
• intraventrikuläre Neoplasien und Läsionen - Überblick
• intraventrikuläres Neurozytom
• Tumoren des Plexus choroideus
• Foramen interventriculare Monroi

und weiter:

• Plexuspapillom