Middle Ear “Adenoma”: a Neuroendocrine Tumor with Predominant L Cell Differentiation

Sylvia L. Asa, Knarik Arkun, Arthur S. Tischler, Adnan Qamar, Fang Ming Deng, Bayardo Perez-Ordonez, Ilan Weinreb, Justin A. Bishop, Bruce M. Wenig, Ozgur Mete

Research output: Contribution to journalArticlepeer-review

7 Scopus citations


This morphological and immunohistochemical study demonstrates that tumors currently known as “middle ear adenomas” are truly well-differentiated epithelial neuroendocrine tumors (NETs) composed of cells comparable to normal intestinal L cells, and therefore, these tumors resemble hindgut NETs. These tumors show consistent expression of glucagon, pancreatic polypeptide, PYY, and the transcription factor SATB2, as well as generic neuroendocrine markers and keratins. The same L cell markers are expressed by cells within the normal middle ear epithelium. These markers define a valuable immunohistochemical profile that can be used for differential diagnosis of middle ear neoplasms, particularly in distinguishing epithelial NETs from paragangliomas. The discovery of neuroendocrine cells expressing the same markers in non-neoplastic middle ear mucosa opens new areas of investigation into the physiology of the normal middle ear and the pathophysiology of middle ear disorders.

Original languageEnglish (US)
Pages (from-to)433-441
Number of pages9
JournalEndocrine Pathology
Issue number4
StatePublished - Dec 2021


  • L cell
  • Middle ear adenoma
  • Neuroendocrine tumor

ASJC Scopus subject areas

  • Pathology and Forensic Medicine
  • Endocrinology, Diabetes and Metabolism
  • Endocrinology


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