Pancreatic PEComa

Last revised by Jeremy Jones on 20 Sep 2021

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.

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

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) 2-3

  • 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

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)
  • nonspecific pancreatic mass
  • heterogeneous echogenicity
  • well-encapsulated

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

​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

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