Pancreatic PEComa

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
A case of
pancreatic PEComa with prominent inflammatory cell infiltration: the inflammatory subtype is a distinct histologic group of PEComa. Abdominal CT and MRI of the pancreatic mass and gross view of the resected specimen. Arrowheads on CT and MRI show the tumor. Abdominal non-enhanced CT shows a solid lesion in the pancreatic tail (A). In the arterial phase of contrast-enhanced abdominal CT, the pancreatic mass does not show contrast enhancement (B). In the excretory phase of contrast-enhanced abdominal CT, enhancement is observed at the margins of the pancreatic mass (C). The mass demonstrates low signal intensity on T1-weighted images (D) and high signal intensity on T2-weighted images (E). Gross view of the resected specimen. The solid tumor is detected in the pancreatic body. The spleen is enlarged (F)
diagnosticpathology.biomedcentral.com • CC-by-4.0
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Pancreatic perivascular epithelioid cell tumors (or "Pancreatic PEComas") are a subtype of the larger family of PEComas. Pancreatic PEComas are very rare with <20 cases described.

Clinical presentation

More common in adults (in contrast to lymphangiomas in the head and neck, which are more common in children). Account for approximately 1% of abdominal lymphangiomas. More common in women

Pathology

As their name suggests, these tumors arise from perivascular epithelioid cells and occur due to a genetic alteration in the tuberous sclerosis gene complex. The PEComas are a group of tumors, including

  • clear cell "sugar" tumors
  • angiomyolipoma
  • lymphangiomyomatosis

The cells are periodic acid-Schiff stain (PAS) positive and diastases sensitive. Immunohistochemistry markers include: smooth muscle and melanocytic markers (SMA, HMB-45, and HMSA-1)

Radiographic features

CT
  • tend to occur in the head and body of the pancreas
  • well-demarcated
  • hypoenhancing mass with a hypervascular capsule
  • may demonstrate hemorrhage or cystic degeneration
  • fat attenuation may be present
MRI

Signal characteristics include

  • T1: hypointense
  • T2: hyperintense
  • T1 C+: heterogeneous enhancement
  • T1 FS: macroscopic fat intensity may be present (saturates on a fat sat sequence)
Ultrasound
  • nonspecific pancreatic mass
  • heterogeneous echogenicity
  • well-encapsulated

Treatment and prognosis

Given the rarity of the lesion, there is no standard treatment

Differential diagnosis

​A pancreatic PEComa should only be considered if a pancreatic mass is well-encapsulated, but since it is so rare, it should never be at the top of a differential. It's probably only reasonably suggested in a patient with tuberous sclerosis and a pancreatic mass.

Other similar pancreatic masses that should be considered before it are

Siehe auch:
Assoziationen und Differentialdiagnosen zu perivaskulärer epitheloidzelliger Tumor (PECom) des Pankreas:
seltene
Pankreastumoren
bmcgastroenterol.biomedcentral.com • CC-by-4.0
perivaskulärer
epitheloidzelliger Tumor (PECom) der Leber
diagnosticpathology.biomedcentral.com • CC-by-4.0