Choroid plexus papilloma: light and electron microscopic study of three cases

Area of Science:

• Neuropathology
• Surgical Pathology
• Tumor Biology

Background:

• Choroid plexus papillomas are rare tumors arising from the choroid plexus epithelium.
• Accurate diagnosis is crucial for appropriate patient management and prognosis.
• Distinguishing these tumors from other papillary neoplasms in the ventricular system can be challenging.

Purpose of the Study:

• To investigate the ultrastructural and histochemical features of choroid plexus papillomas.
• To identify specific cellular markers that can aid in the differential diagnosis of these tumors.
• To compare the observed features with those of normal choroid plexus.

Main Methods:

• Light microscopy and electron microscopy were employed to examine tumor tissues.
• Periodic acid-Schiff (PAS) staining and silver staining were performed.
• Ultrastructural analysis focused on cytoplasmic inclusions and cellular morphology.

Main Results:

• All three cases displayed typical papillary architecture, with two showing solid areas.
• PAS-positive, diastase-resistant, and argyrophilic cytoplasmic inclusions were consistently found.
• Ultrastructurally, these inclusions contained lipid droplets, filamentous material, and microtubules, resembling normal choroid plexus "silver bodies" of Biondi.

Conclusions:

• The presence of characteristic cytoplasmic inclusions, similar to normal choroid plexus "silver bodies," is a key feature of choroid plexus papilloma.
• These inclusions, along with other ultrastructural findings, can assist in differentiating choroid plexus papillomas from other papillary tumors within the ventricular system.
• Further research into these inclusions may enhance diagnostic accuracy for brain tumors.