Sections of the appendix show a dilated lumen containing with abundant purulent exudate. The appendiceal wall exhibits preservation of the mucosal-associated lymphoid tissue, however, there is a dense, diffuse inflammatory infiltrate consisting predominantly of neutrophils. This infiltrate extends from the mucosa, dissecting through the muscularis propria (transmural inflammation), and reaches the periappendiceal adipose tissue (periappendicitis). Admixed lymphocytes and plasma cells are also present within the wall. The lining epithelium shows ulceration and flattening consistent with the gross cystic dilation. There is no evidence of specific granulomas, dysplasia, or malignancy.
Appendicectomy
Appendicectomy specimen measured 5x0.5 cm, with attached mesenteric fat measuring 1 cm. The appendix is almost replaced by a cyst filled with brownish fluid.