Pancreatic Lipomatous Hamartoma: A Hitherto Unrecognized Variant

Am J Surg Pathol. 2018 Jul;42(7):891-897. doi: 10.1097/PAS.0000000000001075.

Abstract

Pancreatic masses consisting of lipomatous components clinically include lipoma, liposarcoma, lipomatous pseudohypertrophy of the pancreas, fat-containing neoplasms such as perivascular epithelioid cell tumor, and malignant neoplasm with lipoid degeneration. We present pancreatic lipomatous hamartoma, which has not been reported hitherto. A solid pancreatic mass was detected from a computed tomographic scan check-up in each of 3 cases of Japanese men. Macroscopically, well-demarcated solid lipomatous masses were detected at the uncus, body, and tail of the pancreas, respectively. Microscopically, the masses predominantly consisted of mature adipocytes with no atypia, but contained characteristics components of pancreatic hamartoma, such as small ducts, a well-preserved acinar structure, and/or fibrous stroma. On the basis of the unique features, lack of islets and absence of periductal elastic fibers, these tumors are a distinct variant of pancreatic hamartoma. Furthermore, high-mobility group AT-hook 2 expression in the fibro-adipocytes of this tumor indicated that these cells are an integral component of the pancreatic lipomatous hamartoma. Consequently, the unique tumors described herein are pancreatic lipomatous hamartoma, which must be discriminated from other lipomatous lesions of the pancreas.

Publication types

  • Case Reports

MeSH terms

  • Adipocytes / chemistry
  • Adipocytes / pathology*
  • Aged
  • Biomarkers / analysis
  • Biopsy
  • Fibroblasts / chemistry
  • Fibroblasts / pathology*
  • HMGA2 Protein / analysis
  • Hamartoma / chemistry
  • Hamartoma / diagnostic imaging
  • Hamartoma / pathology*
  • Hamartoma / surgery
  • Humans
  • Immunohistochemistry
  • Lipomatosis / diagnostic imaging
  • Lipomatosis / metabolism
  • Lipomatosis / pathology*
  • Lipomatosis / surgery
  • Male
  • Middle Aged
  • Pancreatic Diseases / diagnostic imaging
  • Pancreatic Diseases / metabolism
  • Pancreatic Diseases / pathology*
  • Pancreatic Diseases / surgery
  • Terminology as Topic
  • Tomography, X-Ray Computed

Substances

  • Biomarkers
  • HMGA2 Protein
  • HMGA2 protein, human