Colonic chicken skin mucosa: an endoscopic and histological abnormality adjacent to colonic neoplasms.

Objectives: We recently described an endoscopic finding of pale yellow-speckled mucosa adjacent to colonic neoplasms. This resembled the appearance of chicken skin and was named chicken skin mucosa (CSM). CSM differs from previously reported gastrointestinal xanthelasmas in that this entity always occurs in association with colonic neoplasms. The prevalence, endoscopic characteristics, clinical significance, and possible etiology were investigated.

Methods: Eight hundred fifty-two consecutive colonoscopies were prospectively evaluated for the presence of CSM associated with either cancer or adenomas > or = 1 cm. Electron microscopy and histopathology using hemotoxylin and eosin, mucicarmine, and oil red O stains were performed. Twelve consecutive colon cancer resection specimens were prospectively examined to determine the presence of histologic CSM.

Results: CSM was adjacent to eight of 10 distal colorectal cancers, one of four proximal colon cancers, 16 of 42 distal adenomas, and three of 44 proximal adenomas. Four of seven resected distal cancers demonstrated histological evidence of CSM. Biopsies of the CSM revealed that lipid-filled macrophages in the lamina propria were responsible for this endoscopic appearance. Electron microscopy showed that the surface epithelial cells had small intestine-like microvilli. CSM was not seen with other colonic conditions and was not associated with the laxative preparation. In four instances, identification of the CSM alerted the endoscopist to the presence of polyps in locations difficult to visualize.

Conclusions: CSM is an endoscopic entity that occurs as a result of fat accumulation in macrophages in the lamina propria of the mucosa adjacent to colonic neoplasms. Small intestine-like microvilli were present in CSM and the pathophysiological implications remain to be elucidated.