Perivascular epithelioid cell tumors (PEComas)

Intrahepatic

peribiliary perivascular epithelioid cell tumor (PEComa) associated with heterotopic pancreas: A case report. Radiological and macroscopic features of the bile duct and liver tumor. a Magnetic resonance cholangiopancreatography (MRCP). The B2 bile duct is obstructed (arrow) and dilated at its periphery (arrow heads). b Curved multiplanar reconstruction image of contrast-enhanced CT. The liver tumor is visualized as a high-intensity area in the arterial phase (arrow). c Macroscopic view of the tumor. Grayish tumor tissue is observed (arrow)

diagnosticpathology.biomedcentral.com • CC-by-4.0

Perivascular

epithelioid cell tumors (PEComas) • PEComa of the orbit - Ganzer Fall bei Radiopaedia

Gaillard F, PEComa of the orbit. Case study, Radiopaedia.org (Accessed on 26 Jan 2023) https://doi.org/10.53347/rID-57712 • CC by-nc-sa 3.0 (modified)

Perivascular

epithelioid cell tumors (PEComas) • PEComa adjacent to the cecal pole - Ganzer Fall bei Radiopaedia

Nicoletti D, PEComa adjacent to the cecal pole. Case study, Radiopaedia.org (Accessed on 26 Jan 2023) https://doi.org/10.53347/rID-67292 • CC by-nc-sa 3.0 (modified)

Malignant

perivascular epithelioid cell neoplasm in the liver: report of a pediatric case. CT findings. CT shows a 7.7 × 8.8 × 12.0-cm tumor located mainly in S4 and S5 of the liver (a). It was well-circumscribed and showed gradual weak enhancement in both the arterial and portal phases (b)

surgicalcasereports.springeropen.com • CC-by-4.0

Malignant

perivascular epithelioid cell neoplasm in the liver: report of a pediatric case. MRI findings. The tumor shows low intensity on T1-weighted imaging (a) and high intensity on T2-weighted imaging (b) with partial diffusion restriction (c)

surgicalcasereports.springeropen.com • CC-by-4.0

Malignant

perivascular epithelioid cell neoplasm in the liver: report of a pediatric case. FDG-PET findings. FDG-PET shows the tumor to have a high FDG uptake (SUVmax: 8.8) (b) with no signs of distant metastasis (a)

surgicalcasereports.springeropen.com • CC-by-4.0

A successful

case of complete surgical resection via left upper and right lower lobectomy for bilateral lung metastases of a perivascular epithelioid cell tumor in the colon: a case report. Computed tomography and 18F-fluorodeoxyglucose positron emission tomography findings. a A solid nodule (maximum diameter, 2 cm) located centrally in the right lower lobe. b A solid nodule (maximum diameter, 3 cm) located centrally in the left upper lobe. c Maximum standardized uptake value of 8.3 corresponding to the nodule in the right lower lobe. d Maximum standardized uptake value of 5.7 corresponding to the nodule in the left upper lobe

surgicalcasereports.springeropen.com • CC-by-4.0

Perivascular

epithelial cell tumor (PEComa) of the pancreas: a case report and review of previous literatures. Imaging studies. a Ultrasonography showed that gourd-shaped hypo- and iso-echoic mass, 56 mm in size, was detected in the pancreatic head and body. b Enhanced computer tomography showed that solid well-circumscribed low-density mass, 7 cm in diameter, was located in the pancreatic head and body. c Heterogeneously enhanced mass was detected in the pancreatic body by gadolinium-enhanced MRI. d Endoscopic retrograde pancreatography (ERP) showed that main pancreatic duct was slightly deviated downward because of locoregional pressure effect, but direct invasion to the main pancreatic duct was not evident

surgicalcasereports.springeropen.com • CC-by-4.0

Radiopaedia • CC-by-nc-sa 3.0 • de

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

angiomyolipoma (AML)
clear cell 'sugar' tumor of the lung
lymphangioleiomyomatosis (LAM)
clear cell myomelanocytic tumor (CCMMT)
- of the falciform ligament / ligamentum teres
unusual clear tumors of other organs
- pancreas
- rectum
- abdominal serosa
- uterus - considered one of the commonest sites of involvement in the female pelvis
- vulva
- heart
- orbit

Epidemiology

PEComas are far more common in females .

Associations

tuberous sclerosis complex

Pathology

Histology

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

Immunohistochemistry

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

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

Radiographic features

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 . They generally demonstrate prominent contrast enhancement .