Clear cell carcinoid of the appendix: Report of two cases with literature review

Pathol Int. 2015 Jun;65(6):324-8. doi: 10.1111/pin.12284. Epub 2015 Mar 24.

Abstract

The clear cell/lipid-rich change has been described in neuroendocine tumors in several organs, but rarely observed in the appendix. In this study, we describe the morphologic, immunohistochemical features of incidentally discovered appendiceal carcinoids entirely represented by clear cells in a 22-year-old man and a 52-year-old woman. Ultrastructual examination demonstrated abundant lipid droplets and dense core granules. The mechanism leading to lipid accumulation in the cytoplasm has not been discovered, but degenerative processes following recurrent inflammatory change might be considered. This uncommon variant of appendiceal classic carcinoid tumors may bear a superficial resemblance to goblet carcinoid and/or appendiceal metastases from clear cell carcinoma. Awareness of clear cell carcinoid of the appendix will prevent incorrect diagnosis and unnecessary aggressive management.

Keywords: appendix; carcinoid; clear cell; neuroendocrine tumor.

Publication types

  • Case Reports
  • Review

MeSH terms

  • Appendiceal Neoplasms / metabolism
  • Appendiceal Neoplasms / pathology*
  • Appendix / metabolism
  • Appendix / pathology
  • Biomarkers, Tumor / metabolism*
  • Carcinoid Tumor / metabolism
  • Carcinoid Tumor / pathology*
  • Cytoplasm / metabolism
  • Female
  • Humans
  • Male
  • Middle Aged
  • Young Adult

Substances

  • Biomarkers, Tumor