FLORID ANGIOGENESIS IN MUCOSA SURROUNDING AN ILEAL CARCINOID-TUMOR EXPRESSING TRANSFORMING GROWTH-FACTOR-ALPHA

Carcinoid tumors of the gastrointestinal tract are known to be associa ted with fibrosis and vascular elastosis, either within the tumor or a t distant sites. The current report describes prominent vascular proli feration in the villi extending 38 cm proximal and 15 cm distal to an ileal carcinoid tumor. These villi were expanded by vessels, producing a segmental carpet of multiple small polypoid protrusions around the tumor. Immunohistochemical analysis suggested that the major stromal c omponents were of endothelial and myofibroblastic cell origin. The str oma of the tumor itself had minimal fibrosis and vascularity. To our k nowledge, this is the first description of vascular proliferation in t he vicinity but distinct from a carcinoid tumor. The demonstration of transforming growth factor-alpha (TGF-alpha) synthesis by tumor cells supports the possibility of a field effect by angiogenic factor(s) sec reted by the tumor.