klarzelliger myomelanozytischer Tumor

Primary

hepatic perivascular epithelioid cell tumors: imaging findings with histopathological correlation. A 29-year woman with clear-cell myomelanocytic tumor of falciform ligament/ligamentum teres. This patient presented acute pain of upper abdomen and was hospitalized in the emergency department. The non-enhanced CT (a) showed a large heterogeneous mass in the right hepatic lobe with high and low attenuation. Contrast-enhanced CT images (b, arterial phase; c, portal venous phase; d, delayed phase) demonstrated heterogeneous enhancement with necrosis and hemorrhage within the mass. Note the mass was surrounded by dysmorphic vessels (arrow) on arterial phase image. Ultrasound (e) showed an ill-defined, large hyperechoic mass with hypoechoic region within the lesion in the right lobe of liver. The patient was performed percutaneous artery embolization. One month later, she underwent CT and contrast-enhanced MRI to reevaluate the mass. Necrosis, hemorrhage and heterogeneous enhancement were also identified on non-enhanced CT (f) and contrast-enhanced MRI (g, mask T1WI; h, arterial phase; i, portal venous phase; j, delayed phase) images. Note the tumor diameter was decreased from 130 mm to 97 mm

cancerimagingjournal.biomedcentral.com • CC-by-4.0

Hepatic

falciform ligament clear cell myomelanocytic tumor: A case report and a comprehensive review of the literature on perivascular epithelioid cell tumors. Ultrasound scan of the digestive system. A heterogeneous high echogenic mass can be seen in the right liver lobe. An irregular anechoic area is also evident in the mass; color Doppler flow imaging showed no obvious blood signal in it

bmccancer.biomedcentral.com • CC-by-4.0

Hepatic

falciform ligament clear cell myomelanocytic tumor: A case report and a comprehensive review of the literature on perivascular epithelioid cell tumors. Upper abdominal computed tomography scan. A giant tumor can be seen in the right anterior superior segment of the liver. Its internal density is uneven and exhibits a high/low/equal mix

bmccancer.biomedcentral.com • CC-by-4.0

Hepatic

falciform ligament clear cell myomelanocytic tumor: A case report and a comprehensive review of the literature on perivascular epithelioid cell tumors. Upper abdominal dynamic enhancement computed tomography scan. Hepatic arterial enhancement is uneven, but the strengthening of the venous and balance periods is more even

bmccancer.biomedcentral.com • CC-by-4.0

Hepatic

falciform ligament clear cell myomelanocytic tumor: A case report and a comprehensive review of the literature on perivascular epithelioid cell tumors. Magnetic resonance imaging scan of the upper abdomen. The mass exhibits uneven strengthening and the internal liquefied necrotic area has no strength

bmccancer.biomedcentral.com • CC-by-4.0

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klarzelliger myomelanozytischer Tumor

PEComas 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 .