Epithelioid perineurioma: an unusual variant.

An unusual epithelioid variant of perineurioma of the groin occurring in a 53-year-old man is described. The lesion appeared to be associated with a femoral nerve branch. The tumour was characterised by the presence of a syncytial proliferation of epithelioid cells, mimicking a meningioma of syncytial type. In addition there was a minor component of a conventional perineurioma. The tumour cells were EMA+, claudin-1+ and collagen type IV+. Bcl 2 was focally expressed. This case highlights the possibility of a common histogenetic pathway for meningiomas and perineuriomas. Although ultrastructural evidence of possible meningiomatous differentiation within an otherwise histologically typical perineurioma has been described, this is the first reported case of an unconventional epithelioid variant of perineurioma, histologically resembling meningioma.