Fat-predominant mixed epithelial stromal tumor (MEST): report of a unique case mimicking angiomyolipoma

Int J Surg Pathol. 2008 Jan;16(1):73-7. doi: 10.1177/1066896907304523.

Abstract

A unique case of a mixed epithelial stromal tumor (MEST) that was predominantly composed of adipose tissue is reported here. Radiographically and grossly, the lesion was thought to be an angiomyolipoma, based upon its fatty appearance. Microscopically, the lesion was predominantly composed of mature adipose tissue but also contained clusters of bland tubules surrounded by smooth muscle bundles and collagen. By immunohistochemistry, the stroma labeled diffusely for estrogen and progesterone receptors, while the muscle bundles labeled for desmin. Melanocytic markers HMB45 and Melan A, typically positive in angiomyolipoma, were nonreactive. This case expands the morphologic spectrum of MEST to include mimics of angiomyolipoma.

Publication types

  • Case Reports

MeSH terms

  • Adipose Tissue / pathology*
  • Aged
  • Angiomyolipoma / pathology*
  • Antigens, Neoplasm / metabolism
  • Desmin / metabolism
  • Diagnosis, Differential
  • Female
  • Humans
  • Immunohistochemistry
  • Kidney Neoplasms / metabolism
  • Kidney Neoplasms / pathology*
  • Kidney Neoplasms / surgery
  • MART-1 Antigen
  • Melanoma-Specific Antigens
  • Neoplasm Proteins / metabolism
  • Neoplasms, Complex and Mixed / metabolism
  • Neoplasms, Complex and Mixed / pathology*
  • Neoplasms, Complex and Mixed / surgery
  • Nephrectomy
  • Receptors, Estrogen / metabolism
  • Receptors, Progesterone / metabolism

Substances

  • Antigens, Neoplasm
  • Desmin
  • MART-1 Antigen
  • MLANA protein, human
  • Melanoma-Specific Antigens
  • Neoplasm Proteins
  • Receptors, Estrogen
  • Receptors, Progesterone