[Non-encapsulated accumulations of lymphoid tissue in the alimentary tract that form a secretory immune system containing cells committed to IgA or IgE synthesis; It includes Peyer's patches and the lymphoid tissue which is present throughout the gastrointestinal mucosa. ( NCI )]
UMLS (NCI) C0596638 Relation/PAR: secretory immune system
Relation/CHD: Peyer's Patch