Case of the Month

• One large intraventricular mass in the right lateral ventricle in the region of the choroid plexus and one additional mass in the rostral aspect of the right lateral ventricle with severe secondary obstructive ventriculomegaly of the lateral ventricles, right more severe than left, mild periventricular edema, high suspicion of increased intracranial pressure with caudal transtentorial herniation and flow artifacts of the cerebrospinal fluid, as well as syringohydromyelia and edema surrounding it.

• Finding consistent with an intraventricular neoplasia such as a choroid plexus carcinoma with drop metastases in the right ventricle. No signs of other additional drop metastases in the included cranial aspect of the cervical spine.

• No follow up was provided in this case.

• Some literature about choroid plexus tumors:

  • • Choroid plexus tumors in 56 dogs (1985-2007)

    • Choroid plexus carcinoma in a dog - Case report

Magnetic resonance tomography of the head before and after injection of gadolinium contrast media.

Large well-defined mildly irregularly marginated ovoid space-occupying lesion in the right lateral ventricle in the region of the choroid plexus, extending in the region of the junction with the third ventricle. Mass with mildly lobulated with mild heterogeneous signal, mainly hyperintense in the fluid sensitive sequences, T1 hypointense, with strong homogeneous contrast-enhancement, multiple intralesional sensitivity artifacts (consistent with both intralesional bleedings and slow blood flow), and without restricted diffusion. Severe bilateral ventriculomegaly of both lateral ventricles, right more severe than left with mild periventricular hyperintensity in the fluid sensitive sequences without restricted diffusion, consistent with periventricular edema. Rest of the ventricles not distended. Signal of the cerebrospinal fluid with complete suppression in the FLAIR sequence. Severe mass effect of the described mass and of the ventriculomegaly with moderate shift of the midline towards the left, severe flattening of the intrathalamic adhesion, caudal transtentorial herniation, severe crowding in the caudal cerebellar fossa, and mild tipping of the cerebellum into the foramen magnum.
Included aspect of the spinal cord with mild syrinx and mild increased intensity in the region of the dorsal funiculus in the fluid still sensitive sequences.
Additional small well-defined ovoid lesion in the most rostral and ventral aspect of the right lateral ventricle with similar features as the larger described lesion with some tubular susceptibility artifacts, consistent with slow blood flow.
Cerebral sulci flattened with almost complete loss of the visibility of the subarachnoid space. Delineation between gray and white matter well-defined.
Extracalvarial structures within normal limits.

One large intraventricular mass in the right lateral ventricle in the region of the choroid plexus and one additional mass in the rostral aspect of the right lateral ventricle with severe secondary obstructive ventriculomegaly of the lateral ventricles, right more severe than left, mild periventricular edema, high suspicion of increased intracranial pressure with caudal transtentorial herniation and flow artifacts of the cerebrospinal fluid, as well as syringohydromyelia and edema surrounding it.

Finding consistent with an intraventricular neoplasia such as a choroid plexus carcinoma with drop metastases in the right ventricle. No signs of other additional drop metastases in the included cranial aspect of the cervical spine.