Not So Benign: A Rare Atypical Ectopic Choroid Plexus Papilloma

Area of Science:

• Neuro-oncology
• Neurosurgery
• Pathology

Background:

• Choroid Plexus Papillomas (CPPs) are rare brain neoplasms originating from choroid plexus epithelium.
• Atypical CPPs are exceptionally rare, exhibiting aggressive traits like high mitotic activity and early metastasis.
• CPPs constitute 0.4-0.6% of all brain tumors, with atypical variants representing 9% of cases in the SEER database (1978-2009).

Purpose of the Study:

• To report a unique case of an atypical choroid plexus papilloma.
• To highlight the diagnostic challenges posed by its rare cerebellopontine angle location.
• To illustrate the clinical course and neuro-ophthalmic manifestations of this rare tumor.

Main Methods:

• Case report of a 56-year-old woman.
• Clinical presentation, diagnostic imaging, and pathological findings were reviewed.
• Review of literature on atypical choroid plexus papillomas and cerebellopontine angle tumors.

Main Results:

• The patient presented with an atypical choroid plexus papilloma in the cerebellopontine angle, initially misdiagnosed.
• The tumor exhibited leptomeningeal seeding affecting cranial nerves and the spinal cord.
• Neuro-ophthalmic complications, including papilledema and cranial nerve deficits, developed progressively.

Conclusions:

• Atypical choroid plexus papillomas are rare and can present with aggressive behavior and metastasis.
• Ectopic locations, such as the cerebellopontine angle, pose significant diagnostic challenges.
• This case underscores the importance of considering rare diagnoses in challenging clinical scenarios.