Mast Cells Are Activated in the Giant Earlobe Keloids: A Case Series

Yukari Nakajima, Noriko Aramaki, Nao Takeuchi, Ayumi Yamanishi, Yoshiko Kumagai, Keisuke Okabe, Tomoaki Yokoyama, Kazuo Kishi

Research output: Contribution to journalArticlepeer-review


Mast cells and inflammatory cells are abundant in keloid and hypertrophic scar tissues. Even if the cause of physical injury is similar, such as piercing or scratching with hands, clinical findings show differences in the size of keloids in the same area. Hence, we performed histological studies on giant keloids larger than the earlobe, and other smaller keloids. We also examined the risk factors associated with the formation of giant lesions. No statistically significant differences in the association of the risk factors were observed. However, histological observations clearly showed a high number of degranulated or active mast cells with a trend towards a greater number of degranulated mast cells in the giant keloid tissues. Collagen production also tended to increase. Two patients with giant keloids were severely obese, suggesting that the persistent inflammatory state of obesity may also be involved in the growth of keloid lesions.

Original languageEnglish
Article number10410
JournalInternational journal of molecular sciences
Issue number18
Publication statusPublished - 2022 Sept


  • collagen
  • fibroblasts
  • fibrosis
  • inflammation
  • keloids
  • mast cell degranulation
  • obesity

ASJC Scopus subject areas

  • Catalysis
  • Molecular Biology
  • Spectroscopy
  • Computer Science Applications
  • Physical and Theoretical Chemistry
  • Organic Chemistry
  • Inorganic Chemistry


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