Epithelioid perineurioma: an unusual variant

Area of Science:

• Surgical Pathology
• Oncology
• Neuroscience

Background:

• Perineuriomas are rare tumors originating from peripheral nerve sheath cells.
• Meningiomas arise from the meninges, the membranes surrounding the brain and spinal cord.
• While distinct, perineuriomas and meningiomas share some immunohistochemical markers and potential histogenetic links.

Observation:

• A unique case of an epithelioid variant of perineurioma associated with a femoral nerve branch in a 53-year-old male is presented.
• The tumor exhibited a syncytial proliferation of epithelioid cells, histologically resembling a syncytial meningioma.
• A minor component of conventional perineurioma was also identified within the lesion.

Findings:

• Immunohistochemical analysis revealed tumor cells positive for epithelial membrane antigen (EMA), claudin-1, and collagen type IV.
• Focal expression of Bcl-2 was noted.
• The epithelioid morphology and immunophenotype suggest a possible meningiomatous differentiation.

Implications:

• This case supports the hypothesis of a common histogenetic pathway between meningiomas and perineuriomas.
• The findings expand the spectrum of perineurial tumor variants and their differential diagnoses.
• Recognizing this variant is crucial for accurate diagnosis and appropriate patient management.