Epithelioid cell

It is generally accepted that Epithelioid cells (also called Epithelioid histiocytes) are activated macrophages resembling epithelial cells.[1] [2][3]Structurally, they are elongated, with finely granular, pale eosinophilic (pink) cytoplasm, and central, ovoid nuclei (oval or elongate), which are less dense than that of a lymphocyte.[4] They have indistinct shape and often appear to merge into one another, forming aggregates known as giant cells.[4] Epithelioid cells are central in the formation of granulomas, which are associated with many serious diseases.[4]

Clinical significance

Epithelioid cells are an essential characteristic of granulomas: without them a histological finding is not a granuloma.[5] A granuloma can be defined as an organized collection of epithelioid macrophages. More broadly, a granuloma may be considered an organized collection of macrophages, including mere collections of giant cells surrounding inert substances like suture material – the so-called "non-immune granulomas." Granuloma formation is associated with pathogens that have learned to evade the host immune system by various means like resisting phagocytosis and killing within the macrophages. Indigestibility of matter by macrophages is a common feature of granulomatous inflammation.[4] Granulomas try to wall off these organisms and prevent their further growth and spread. Historically widespread and destructive diseases such as tuberculosis, leprosy and syphilis are granulomatous conditions. Granuloma formation is also the feature of many more contemporary conditions, like fungal infections, sarcoidosis and Crohn's diseases.[4]

See also


  1. "Dorlands Medical Dictionary:epithelioid cell".
  2. Van Furth R, Cohn ZA, Hirsch JG, Humphrey JH, Spector WG, Langevoort HL (1972). "The mononuclear phagocyte system: a new classification of macrophages, monocytes, and their precursor cells". Bull World Health Organ. 46 (6): 845–52. PMID 4538544.
  3. Ramakrishnan L (April 2012). "Revisiting the role of the granuloma in tuberculosis". Nat Rev Immunol. 12 (5): 352–66. doi:10.1038/nri3211. PMID 22517424.
  4. Cross S (2018-04-30). Underwood's pathology : a clinical approach. Cross, Simon S. (Seventh ed.). Edinburgh. ISBN 9780702072123. OCLC 1040695915.
  5. Turk JL, Narayanan RB (April 1982). "The origin, morphology, and function of epithelioid cells". Immunobiology. 161 (3–4): 274–82. doi:10.1016/S0171-2985(82)80083-1. PMID 7047374.
  • Epithelioid+cells at the US National Library of Medicine Medical Subject Headings (MeSH)
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