Chronic appendicitis can have milder symptoms that last for a long time, and that disappear and reappear. It can go undiagnosed for several weeks, months, or years. Acute appendicitis has more severe symptoms that appear suddenly within 24 to 48 hours . Acute appendicitis requires immediate treatment.

Mucocele of the appendix is a descriptive term that refers to dilation of the appendiceal lumen as a result of mucin accumulation and is based on the gross or macroscopic appearance of the appendix. Mucocele formation is most commonly caused by epithelial proliferation, either benign or malignant.

Appendiceal neoplasms are uncommon tumors of the gastrointestinal tract that may manifest with symptoms of appendicitis, right lower quadrant pain, or palpable mass, leading to imaging or surgical intervention. The majority of appendiceal masses consist of primary epithelial neoplasms and neuroendocrine tumors (NETs).