3. DISCUSSION
Ulcerative colitis (UC) is a chronic non-specific inflammatory bowel
disease characterized by recurrent symptoms such as abdominal pain,
diarrhea, and bloody mucous stools. The disease typically follows a
chronic course with alternating periods of flare-ups and remission, and
in some cases, symptoms may persist and gradually worsen. UC usually
begins in the rectum and progresses proximally, potentially affecting
the entire colon, including the terminal ileum. Appendiceal orifice
inflammation (AOI) refers to congestion, erosion, and ulcers at the
appendiceal orifice. When AOI co-occurs with UC, its inflammatory
characteristics resemble the pathological features of UC. There is
increasing evidence to suggest that AOI represents a skip lesion in the
mucosa of UC [1]. Research indicates that AOI is more common in UC
patients with mild to moderate distal colonic involvement [2].
However, retrospective studies have shown conflicting results, with some
suggesting that AOI is more prevalent in moderate to severe UC, possibly
serving as a marker of active disease and an indicator of disease
severity [3].
The presence of AOI in UC patients has been associated with differing
outcomes and responses to treatment. Wu and colleagues conducted a
retrospective study involving 202 UC patients, of which 116 had AOI.
They found a significant difference in the cumulative risk of endoscopic
complete remission between the AOI and non-AOI groups, indicating a
lower rate of endoscopic complete remission in UC patients with AOI
[4]. In a long-term follow-up study by Oh and colleagues involving
318 UC patients, 140 of whom had AOI, the AOI group demonstrated a lower
rate of endoscopic complete remission compared to the non-AOI group.
However, there were no significant differences between the two groups in
terms of other clinical parameters, including the use of biologics,
hospitalization rates, and proximal disease extension [5].
Conversely, a retrospective analysis by Kyong and colleagues, involving
376 UC patients with an average follow-up time of 66.1 months, revealed
no significant differences between the AOI and non-AOI groups in terms
of endoscopic remission, hospitalization rates, recurrence rates, or the
use of corticosteroids, immunosuppressants, and biologics [6].
Therefore, the role of AOI in predicting the prognosis of UC patients
remains inconclusive.
Pathologically, AOI does not possess specific characteristics. A study
analyzing 26 cases with histological abnormalities at the appendiceal
orifice found active inflammation in 12 cases, chronic active
inflammation in 13 cases, and one case resembling collagenous colitis.
Additionally, eight patients with inflammation in other biopsy samples
were eventually diagnosed with ulcerative colitis, with none of the
patients isolated to the appendiceal orifice showing clinical symptoms
during follow-up. As such, isolated inflammation of the appendiceal
orifice mucosa should not be regarded as a sign of inflammatory bowel
disease progression or as a distinguishing feature of other chronic
colonic inflammations [7]. Nevertheless, while AOI is not uncommon
in UC patients, it is often reported as a manifestation of ”skip
inflammation” within UC, and cases of isolated AOI are rarely reported.
Although this case is an isolated instance, it is noteworthy due to its
complete follow-up data. The patient initially presented with isolated
AOI at disease onset, exhibiting symptoms such as abdominal pain and
altered bowel habits. Pathological biopsy results indicated acute
cryptitis, and treatment with mesalazine resulted in significant symptom
relief and improved endoscopic findings. Subsequent symptom recurrence,
followed by reinitiation of treatment, also led to noticeable
improvements in symptoms and endoscopic appearance. Consequently, based
on symptoms, endoscopic findings, histopathology, and treatment
response, the patient was diagnosed with UC, and mesalazine treatment
proved effective. This case highlights that UC can occasionally present
as isolated AOI without other manifestations of gastrointestinal
involvement. Clinical symptom variations aligned with endoscopic changes
in AOI, suggesting that AOI can serve as an indicator of UC disease
activity. The patient has been followed up for over four years with no
evidence of other colonic involvement. Future follow-ups will monitor
for potential involvement of other colonic segments.