Reactive lymphoid hyperplasia of the appendix in children: a descriptive analysis of accompanying neural and stromal features.

Background: Reactive lymphoid hyperplasia (RLH) is frequently identified in pediatric appendectomy specimens performed for suspected acute appendicitis. However, its associated neural and stromal alterations remain incompletely characterized. Methods: This retrospective descriptive study evaluated pediatric appendectomy specimens obtained between January 2019 and January 2024. RLH cases were identified based on histopathological criteria. Archived specimens were re-evaluated using hematoxylin and eosin staining, S-100 immunohistochemistry, and Masson's trichrome staining. Neural alterations were classified according to Höfler's criteria, and fibrosis was graded semiquantitatively. Results: Among 468 appendectomies, 100 cases fulfilled the criteria for RLH. The mean age was 11.34 ± 4.31 years, and 63% were male. Neural and stromal alterations, including S-100-positive nerve elements and varying degrees of fibrosis, were frequently observed. Höfler Type 1 and Type 3 patterns were the most common, and fibrosis was predominantly mild to moderate. Postoperative symptom resolution was observed in patients with available follow-up. Conclusion: RLH in children is commonly associated with reactive neural and stromal alterations. However, these findings should be interpreted as nonspecific reactive changes rather than disease-specific features. Further studies are needed to clarify their clinical significance.