We report the clinical-pathologic study of 8 cases of pediatric benign, postobstructive, appendiceal mucus retention in patients 3-15 years of age. The appendices showed very limited acute inflammation. Their most significant change consisted of minimal to mild dilatation of the distal lumen, which was filled with mucus and lined by an epithelium showing often dramatic increase in mucus cells devoid of atypia and without any of the villous proliferation reported in instances of “mucosal hyperplasia” observed in adult patients. In all 8 cases, there was seepage of mucus through the appendiceal wall into the surrounding tissue, eliciting a macrophagic reaction. Proximal to the zones of mucus retention, the lumen of 2 of the appendices was obstructed by a fecalith, and 2 exhibited fibrous obliteration of the lumen at that site. We believe the condition results from obstruction and focal inflammation, which isolate the distal portion of the appendix and elicit goblet cell metaplasia, the secretion of which is followed by luminal distention, eventual rupture, and seepage of mucus within the wall and the mesoappendix. The clinical and radiologic picture of this condition may be mistaken for that of an acute appendicitis complicated by rupture and abscess formation. The report provides an opportunity to describe and characterize “appendiceal mucosal goblet cell metaplasia,” a seldom mentioned entity associated with benign appendiceal obstructive mucus retention in children.