Stump appendicitis is acute inflammation of the residual appendiceal stump after prior appendectomy (laparoscopic or open). Despite low incidence (1/50,000 appendectomies), it poses a significant diagnostic challenge — the patient and clinician consider 'appendicitis ruled out.' Risk increases when stump length exceeds >5 mm. On CT, an inflammatory short tubular structure at the cecal base, peristump fat stranding, and surgical material (clips/sutures) together lead to diagnosis. Diagnostic delays may cause serious complications such as perforation, abscess, and sepsis. The interval between initial appendectomy and stump appendicitis can range from days to years (average 8-10 years).
Age Range
10-80
Peak Age
40
Gender
Male predominant
Prevalence
Rare
Stump appendicitis is inflammation of the residual appendiceal stump left during appendectomy. Pathophysiology is identical to primary acute appendicitis: obstruction of the stump lumen (fecalith, lymphoid hyperplasia, adhesion, or kinking) increases intraluminal pressure, mucosal barrier disrupts, and bacterial translocation occurs. When stump length exceeds >5 mm, sufficient luminal space remains and obstruction risk increases. Stump length may be harder to control during laparoscopic appendectomy — some series report higher stump appendicitis rates after laparoscopic procedures. Inflammation affects the stump wall transmurally and spreads to surrounding tissues — this appears as peristump fat stranding on CT. Incomplete appendectomy after perforated primary appendicitis (inability to identify the stump) is a specific risk factor. On CT, the inflammatory stump structure appears as a short tubular structure at the cecal base — presence of surgical clips or suture material confirms the prior operation and guides diagnosis.
The combination of surgical clips or suture material with an inflammatory, dilated short tubular structure (stump) and peristump fat stranding at the cecal base is pathognomonic for stump appendicitis. This triad — surgical material + inflammatory stump + fat stranding — confirms diagnosis when combined with prior appendectomy history. Clinician recognition of this combination can be lifesaving because diagnostic delay leads to 60-70% perforation rate.
Inflammatory, dilated short tubular structure (stump) at the cecal base. Stump diameter >5 mm with wall thickening (>3 mm). Lumen may be filled with fluid or fecal material. Unlike the complete appendix, the stump is short (usually <3 cm) and terminates at the cecal base.
Report Sentence
A short tubular inflammatory structure (appendiceal stump) measuring approximately ___ mm in diameter with thickened wall is seen at the cecal base, consistent with stump appendicitis.
Increased density in fat tissue surrounding the stump (fat stranding). Indicates transmural spread of inflammation to peristump tissues. Same mechanism as periappendiceal fat stranding in primary appendicitis — but localization is limited to the cecal base.
Report Sentence
Significant peristump fat stranding is observed surrounding the appendiceal stump.
Metallic surgical clips or suture material at the cecal base. Direct CT evidence of prior appendectomy. Clips are seen at the proximal end of the stump (closure line) and serve as a reference point for identifying the stump.
Report Sentence
Surgical clips/suture material from prior appendectomy are seen at the cecal base.
Non-compressible short tubular structure (stump) at the cecal base. Increased echogenicity in surrounding fat tissue (inflammation). Evaluated with graded compression technique. Unlike the full appendix, the structure is short and does not terminate as a blind-ending tube — it ends at the surgical closure point.
Report Sentence
A non-compressible short tubular structure measuring approximately ___ mm in diameter with surrounding hyperechoic fat tissue is seen at the cecal base, consistent with stump appendicitis.
T2 hyperintensity in the stump (inflammatory edema). T2 signal increase is also seen in peristump tissues. T2 fat-sat sequences best demonstrate peristump edema. Preferred as radiation-free alternative in pregnant women and young patients.
Report Sentence
T2 signal increase in the appendiceal stump and peristump tissue edema are observed, consistent with stump appendicitis.
In complicated stump appendicitis: stump wall discontinuity, peristump free fluid, extraluminal air, abscess formation (rim-enhancing collection). Perforation rate in stump appendicitis is higher than primary appendicitis (60-70% vs 20-30%) because diagnosis is delayed.
Report Sentence
Free fluid/air surrounding the appendiceal stump and a rim-enhancing collection measuring ___ cm are seen, consistent with perforated stump appendicitis.
Criteria
Inflammatory stump, peristump fat stranding present. No perforation, abscess, or free air. Rare subtype — most cases present as complicated.
Distinct Features
Treated with completion appendectomy. Early diagnosis prevents complications. Antibiotics + elective surgery may be planned.
Criteria
Stump wall discontinuity, extraluminal air, free fluid. Develops in 60-70% of cases (much higher than primary appendicitis). Diagnostic delay is the main cause.
Distinct Features
Requires emergency surgery. High morbidity. Cecal resection may be needed (the stump's cecal attachment area may show extensive inflammation).
Criteria
Peristump rim-enhancing fluid collection. Localized infection contained by omental and bowel adhesion.
Distinct Features
Initial treatment with percutaneous drainage + IV antibiotics. Delayed completion appendectomy 6-8 weeks later. Adhesions from prior surgery may complicate drainage.
Distinguishing Feature
In primary acute appendicitis, the full appendix is dilated and inflamed — no surgical clips or evidence of prior appendectomy. In stump appendicitis, the stump is short and accompanied by surgical material. Clinical history (prior appendectomy) is key to differential diagnosis.
Distinguishing Feature
Differentiation from cecal diverticulitis: Diverticulitis shows focal thickening of the cecal wall and inflammatory diverticulum, no tubular stump structure. In stump appendicitis, the short tubular stump and surgical clips are diagnostic. Cecal base inflammation is present in both conditions.
Distinguishing Feature
Crohn disease shows terminal ileum thickening, skip lesions, comb sign, and fistula tracts — multifocal involvement is typical. In stump appendicitis, findings are isolated to the cecal base and stump. Surgical clips are not found in Crohn's (unless prior appendectomy).
Distinguishing Feature
Cecal adenocarcinoma shows mass formation, apple-core appearance, and regional lymphadenopathy — a more chronic process. Stump appendicitis presents with acute inflammatory findings (fat stranding, wall enhancement). Surgical clips are not expected in adenocarcinoma.
Urgency
emergentManagement
surgicalBiopsy
Not NeededFollow-up
no-follow-upStump appendicitis is an emergency surgical indication — requires completion appendectomy (stump resection). Diagnostic delay is the greatest risk: perforation develops in 60-70% of cases (vs 20-30% in primary appendicitis). The delay occurs because the patient and clinician consider appendicitis ruled out. Critical message for radiologists: stump appendicitis should be considered in patients with prior appendectomy presenting with right lower quadrant pain and cecal base inflammation. Surgical clips should be sought on CT and the stump structure evaluated. Keeping the stump <3 mm during initial appendectomy is preventive. Cecal resection may be needed in complicated cases. Pathologic examination is mandatory for exclusion of tumor (carcinoid, mucinous neoplasm).
Requires completion appendectomy (stump resection). Diagnosis may be delayed if surgical history is unknown, leading to complications (perforation, abscess). Stump length >5 mm is a risk factor. Keeping the stump short (<3 mm) during initial surgery is preventive.