The jejunum is the midsection of the small intestine, connecting the duodenum to the ileum. It is about 2.5 m long, and contains the plicae circulares, and villi that increase its surface area. Products of digestion (sugars, amino acids, and fatty acids) are absorbed into the bloodstream here.
Not to be confused with the cells of the islets of Langerhans, found in the pancreas, or Langhans giant cell.
Langerhans cell histiocytosis (LCH) is a rare cancer that begins in LCH cells (a type of dendritic cell which fights infection). Sometimes there are mutations (changes) in LCH cells as they form. These include mutations of the BRAF gene. These changes may make the LCH cells grow and multiply quickly.