Choroid plexus neoplasms. Clinicopathologic and immunohistochemical studies

Area of Science:

• Neuro-oncology
• Pathology
• Immunohistochemistry

Background:

• Choroid plexus neoplasms (CPNs) are rare intracranial tumors, comprising less than 1% of all brain tumors.
• Choroid plexus papillomas (CPPs) are more common than choroid plexus carcinomas (CPCs).
• Limited immunocytochemical characterization exists for these neoplasms.

Purpose of the Study:

• To investigate the immunocytochemical profiles of choroid plexus neoplasms (CPNs).
• To differentiate between benign choroid plexus papillomas (CPPs) and malignant choroid plexus carcinomas (CPCs).
• To establish a classification rule for CPNs based on immunohistochemical markers.

Main Methods:

• Retrospective analysis of ten CPN cases (seven CPPs, three CPCs) over 25 years.
• Immunohistochemical examination using polyclonal and monoclonal antibodies against various proteins including keratin, GFAP, S100, CEA, and CKER.
• Statistical analysis to develop a classification rule.

Main Results:

• Keratin and cytokeratin (CKER) were detected in both CPPs and CPCs, potentially distinguishing them from ependymomas.
• Positivity for carcinoembryonic antigen (CEA) was associated with a more aggressive histologic pattern and worse prognosis in CPCs.
• S100 immunoreactivity was more prevalent in well-differentiated neoplasms (CPPs).

Conclusions:

• Immunohistochemistry, particularly using CEA and S100 markers, can aid in differentiating benign and malignant choroid plexus neoplasms.
• A classification rule was proposed: positive CEA and negative S100 indicate malignancy; otherwise, the tumor is benign.
• Further characterization of CPNs through immunohistochemistry is crucial for accurate diagnosis and prognosis.