Perivascular Epithelioid Cell Tumour with Intraorbital Location: Report of a Case and Review of the Literature.

The Perivascular Epithelioid Cell tumours (PEComas) are rare mesenchymal neoplasms recognized as entity by the World Health Organization. The tumour cells have an uncertain origin and are characterized by distinctive histological and immunohistochemical features. We report a case of PEComa occurring as intraorbital lesion in a 47-year-old man. We found only two other cases described in the literature and we considered all three cases together in order of histology, immunohistochemistry, and clinical outcome. We found a strict histological overlapping and quite similar immunohistological results. All three cases showed a favourable clinical course probably related to small size of tumours (<5 cm), low mitotic rate (<2 mitoses in 50 HPF), and absence of necrosis.