Lymphocytic Appendicitis: Definition and Clinical Significance
Lymphocytic appendicitis is a histopathological variant of appendicitis characterized by a predominant lymphocytic infiltration of the appendiceal wall, representing a possible regression phase of acute appendicitis or a distinct inflammatory pattern with different clinical implications.
Definition and Histopathological Features
Lymphocytic appendicitis is defined by the following histological characteristics:
- Dense lymphocytic infiltrate in the subserosa and/or muscularis propria of the appendix
- Fewer neutrophils compared to classic phlegmonous appendicitis
- Often multifocal rather than diffuse pattern of infiltration
- May include eosinophils admixed with lymphocytes 1
- Absence of significant neutrophilic infiltration that characterizes typical acute appendicitis
Epidemiology and Significance
- Represents approximately 32.5% of non-complicated appendicitis cases according to some studies 1
- May indicate a resolving phase of acute appendicitis
- Can be part of a spectrum of appendiceal inflammation with different clinical presentations
Clinical Correlation
The clinical presentation of lymphocytic appendicitis can be similar to classic acute appendicitis:
- Right lower quadrant pain
- Nausea and vomiting
- Fever may be present but less consistently than in neutrophilic appendicitis
- Laboratory findings may show less pronounced inflammatory markers
However, some key differences exist:
- May represent a later stage in the evolution of appendicitis
- Associated with longer duration of symptoms before presentation 1
- May be associated with recurrent right lower quadrant pain in some cases 2
Diagnostic Considerations
Diagnosis is primarily histopathological and made after appendectomy:
- Cannot be reliably distinguished from classic appendicitis preoperatively
- Standard imaging (CT, ultrasound) cannot specifically identify the lymphocytic variant
- Neutrophil-to-lymphocyte ratio (NLR) may be lower compared to classic acute appendicitis 3, 4
Differential Diagnosis
Lymphocytic appendicitis should be distinguished from:
- Classic neutrophilic (phlegmonous) appendicitis
- Chronic appendicitis (persistent lymphocytic infiltration with fibrosis)
- Enterocolic lymphocytic phlebitis involving the appendix 5
- Normal appendix with incidental lymphoid hyperplasia
- Early manifestation of inflammatory bowel disease affecting the appendix
Clinical Management
Management follows the same principles as for acute appendicitis:
- Surgical removal (appendectomy) remains the standard treatment
- The lymphocytic pattern is typically identified only after histopathological examination
- No specific different treatment is required based on the lymphocytic pattern alone
Prognostic Implications
- Generally associated with a favorable prognosis
- May represent a self-limiting form of appendicitis
- Lower risk of perforation compared to neutrophilic appendicitis
Research Considerations
- Further studies are needed to determine if lymphocytic appendicitis represents:
- A distinct entity
- A resolving phase of classic appendicitis
- An early or mild form of appendicitis
- A response to different pathogenic triggers
Clinical Pitfalls
- Mistaking lymphocytic appendicitis for a normal appendix histologically
- Underestimating the clinical significance of lymphocytic infiltration
- Failing to recognize that lymphocytic appendicitis can cause genuine appendicitis symptoms despite different histology
- Not considering lymphocytic appendicitis in cases of recurrent right lower quadrant pain
Understanding lymphocytic appendicitis is important for accurate histopathological classification and may have implications for understanding the natural history and pathophysiology of appendicitis.