The histopathological diagram of the appendix shown above demonstrates features consistent with which of the following conditions?

Explanation

## Image Findings * **Inflammatory exudate** is visible within the lumen of the appendix. * The **mucosa appears ulcerated**. * **Lymphoid follicles** are prominent in the submucosa. * There is significant **neutrophilic infiltration** extending into the **muscularis propria**. ## Diagnosis **Key Point:** The presence of neutrophilic infiltration extending into the muscularis propria is the histological hallmark of **acute appendicitis**. The diagram clearly illustrates the key pathological features of acute appendicitis. The lumen contains inflammatory exudate, and the mucosal lining shows ulceration, indicating acute injury. The most crucial diagnostic criterion is the transmural inflammation, specifically the infiltration of neutrophils beyond the muscularis mucosa into the muscularis propria. This finding confirms an acute inflammatory process involving the entire wall of the appendix. ## Differential Diagnosis | Feature | Acute Appendicitis | Crohn's Disease (Appendix) | Diverticulitis (Colon) | Carcinoid Tumor (Appendix) | | :---------------------- | :------------------------------------------------- | :----------------------------------------------------------- | :--------------------------------------------------------- | :------------------------------------------------------- | | **Key Histology** | Neutrophilic infiltration into muscularis propria | Transmural inflammation, granulomas, crypt abscesses | Inflammation around a diverticulum, pericolic inflammation | Nests/cords of uniform cells, salt-and-pepper chromatin | | **Inflammation Type** | Acute, neutrophilic | Chronic, granulomatous | Acute/chronic, often pericolic | Neoplastic, minimal inflammation unless complicated | | **Mucosal Changes** | Ulceration, exudate | Skip lesions, cobblestoning, deep ulcers | Inflammation, perforation if severe | Usually intact, unless tumor causes obstruction/ischemia | | **Lymphoid Follicles** | Often prominent (hyperplasia) | May be present, but not primary diagnostic feature | Not a primary feature | Not a primary feature | ## Clinical Relevance **Clinical Pearl:** Acute appendicitis typically presents with periumbilical pain migrating to the right lower quadrant, associated with anorexia, nausea, vomiting, and fever. Early diagnosis and surgical intervention (appendectomy) are crucial to prevent complications like perforation and peritonitis. ## High-Yield for NEET PG **High-Yield:** The definitive histological criterion for acute appendicitis is the presence of **neutrophils within the muscularis propria**. **Key Point:** Lymphoid hyperplasia is a common cause of luminal obstruction, leading to appendicitis, especially in younger individuals. ## Common Traps **Warning:** Merely finding inflammatory cells in the mucosa or submucosa is insufficient for diagnosing acute appendicitis; the inflammation **must extend into the muscularis propria**. This distinction is often tested. ## Reference [cite:Robbins and Cotran Pathologic Basis of Disease, Chapter 15: The Gastrointestinal Tract]