Appendicitis

Author: Mikael Häggström
Appendicitis may histopathologically be defined as neutrophilic infiltrates of the wall of the appendix in the correct clinical context.

  See also: General notes on fixation

Comprehensiveness

On this resource, the following formatting is used for comprehensiveness:

• Minimal depth
• (Moderate depth)
• ((Comprehensive))

Gross proccessing

Acute appendicitis: The organ is enlarged and sausage-like (botuliform). This longitudinal section shows red inflamed mucosa with an irregular luminal surface. It was removed early in the disease, with no late complications like transmural necrosis, perforation, and abscess formation.

Standard sections if the appendix appears inflamed and there are no signs of malignancy. Further information: Appendix

Microscopic evaluation

• Evaluate depth of the inflammation.
• Look for any perforation of the wall.
• Look for thrombosis, indicating gangrenous appendicitis.

|- ! Pattern !! Gross pathology !! Light microscopy !! Clinical significance |- ! Acute intraluminal inflammation | None visible ||

• Only neutrophils in lumen
• No ulceration or transmural inflammation

| Probably none |- ! Acuta mucosal inflammation | None visible ||

• Neutrophils within mucosa, and possibly in submucosa
• Mucosal ulceration

| May be secondary to enteritis. |- ! Suppurative acute appendicitis | May be inapparent.

• Dull mucosa
• Congested surface vessels
• Fibropurulent serosal exudate in late cases
• Dilated appendix

|

• Neutrophils in mucosa, submucosa and muscularis propria, potentially transmural.
• Extensive inflammation
• Commonly intramural abscesses
• Possibly vascular thrombosis

| Can be presumed to be primary cause of symptoms |- ! Gangrenous/necrotizing appendicitis |

• Friable wall
• Purple, green or black color

|

• Transmural inflammation
• Necrotic areas
• Extensive mucosal ulceration

| Will perforate if untreated |- ! Periappendicitis | May be inapparent.

• Serosa may be congested, dull and exudative

|

• Serosal and subserosal inflammation, no further than outer muscularis propria

| Probably secondary to other disease |- ! Eosinophilic appendicitis | None visible |

• >10 eosinophils/mm² in muscularis propria.
• No changes conforming to other types of appendicitis

| Possibly parasitic, or eosinophilic enteritis. |}

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