Perivascular epithelioid cell tumour, also known as PEComa or PEC tumour, is a family of mesenchymal tumours consisting of perivascular epithelioid cells (PECs).[1] These are rare tumours that can occur in any part of the human body.
The cell type from which these tumours originate remains unknown. Normally, no perivascular epitheloid cells exist; the name refers to the characteristics of the tumour when examined under the microscope.[2]
Establishing the malignant potential of these tumours remains challenging although criteria[3] have been suggested; some PEComas display malignant features whereas others can cautiously be labeled as having 'uncertain malignant potential'.[2] The most common tumours in the PEComa family are renalangiomyolipoma and pulmonarylymphangioleiomyomatosis, both of which are more common in patients with tuberous sclerosis complex. The genes responsible for this multi-system genetic disease have also been implicated in other PEComas.[2]
Many PEComa types shows a female predominance in the sex ratio.
Cause
The precursor cell of PEComas is currently unknown; there is no normal counterpart "perivascular epitheloid cell".[1] Genetically, PECs are linked to the tuberous sclerosisgenesTSC1 and TSC2, although this link is stronger for angiomyolipoma and lymphangioleiomyomatosis than for other members of the PEComa family.[4]
Diagnosis
Histology
PECs consist of perivascular epithelioid cells with a clear/granular cytoplasm and central round nucleus without prominent nucleoli.
^Folpe AL, Mentzel T, Lehr HA, Fisher C, Balzer BL, Weiss SW (Dec 2005). "Perivascular epithelioid cell neoplasms of soft tissue and gynecologic origin: a clinicopathologic study of 26 cases and review of the literature". Am J Surg Pathol. 29 (12): 1558–75. doi:10.1097/01.pas.0000173232.22117.37. PMID16327428.