Perivascular epithelioid cell tumors (PEComas)

Perivascular epithelioid cells tumors (PEComas) are a group of related mesenchymal tumors and tumor-like conditions found in many locations. This group includes:

PEComas are far more common in females 4

All PEComas share similar and distinctive cellular morphology – peripheral epitheloid cells – which have no counterpart in normal tissue 4. These tumors appear as sheets and nests of epithelioid or spindle-shaped cells associated with blood vessel walls. They have granular eosinophilic cytoplasms. 

PEComas are characterized by immunoreactivity to smooth muscle and melanocytic markers 4.

  • smooth muscle: actin, desmin
  • melanocytic: HMB-45, melan-A

Unfortunately, due to non-specific imaging appearances and the scarcity of reported cases no specific imaging features are recognized. These lesions seem to usually be solid but can be centrally necrotic 5-7. They generally demonstrate prominent contrast enhancement 6

PEComas usually behave in a benign fashion although local recurrence and even malignant behavior are encountered, mimicking malignant sarcomas. 

Surgical excision is usually curative. 

The differential diagnosis is broad and largely depends upon the location of the mass.

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Article information

rID: 9985
Tag: cases, refs
Synonyms or Alternate Spellings:
  • Perivascular epithelioid cell tumours (PEComa)
  • PEComa
  • PEComas
  • Perivascular epithelioid cell tumours (PEComas)
  • Perivascular epithelioid cell tumors (PEComa)
  • Perivascular epithelioid cell tumor (PEComa)
  • Peri-vascular epithelioid cell tumor (PEComa)

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Cases and figures

  • Case 1: PEComa of the orbit
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