A new structure of small intensely fluorescent cells in superior mesenteric ganglion of human fetus.

Superior mesenteric ganglia of six fetuses (35-40 weeks old) were investigated by histochemical fluorescent method. In addition to solitary SIF cells and clusters of SIF cells reported previously, a new structure of SIF cells was found and named "SIF-cell nodule". The SIF-cell nodule was composed of a large number of SIF cells and was encapsulated by dense connective tissue. Some blood vessels and nerve fibers entered the nodule. Based on the morphology, we speculated that SIF-cell nodule might be an endocrine gland.