Histopathological Spectrum of the Human Appendix with Aging and Adiposity: A Forensic Autopsy Study

Background: Histological variation in the vermiform appendix in forensic autopsy populations remains incompletely characterized. This study evaluated age- and adiposity-related histopathological patterns and their potential medico-legal relevance. Methods: This prospective cross-sectional study included 101 consecutive adult forensic autopsy cases. Appendiceal specimens were assessed semi-quantitatively for lymphoid nodules, fibrosis, luminal narrowing, and submucosal adipose accumulation, with morphometric assessment of the submucosa-to-muscularis propria ratio. Associations with age and adiposity measures were examined using correlation analyses and multivariable ordinal regression. Postmortem interval (PMI) and natural versus non-natural cause of death were evaluated in sensitivity analyses. Results: Advancing age was associated with lower lymphoid nodule scores (ρ = −0.301, p = 0.002) and higher fibrosis (ρ = 0.403, p < 0.001), luminal-status (ρ = 0.228, p = 0.022), and submucosal-adipose-accumulation scores (ρ = 0.302, p = 0.002). In adjusted models, age remained associated with lower lymphoid scores (OR = 0.971, 95% CI 0.951–0.992) and higher submucosal adipose accumulation (OR = 1.027, 95% CI 1.007–1.048), while fibrosis showed threshold-specific age associations (ORs = 1.039 and 1.087; 95% CIs 1.013–1.065 and 1.050–1.125). Unadjusted associations between adiposity measures and histopathological outcomes were modest. Greater abdominal subcutaneous fat thickness was associated with higher luminal-status (OR = 1.212, 95% CI 1.027–1.431) and submucosal-adipose-accumulation scores (OR = 1.203, 95% CI 1.022–1.416) after adjustment for age and sex. In the three-level luminal sensitivity model, the age estimate was essentially unchanged after adding PMI, and PMI was not significant. After additional adjustment for cause of death, age associations with fibrosis and submucosal adipose accumulation remained significant, whereas those with lymphoid nodule score and luminal status did not. Conclusions: Age showed the most consistent associations with appendiceal histological variation, particularly fibrosis and submucosal adipose accumulation. Adiposity-related associations were modest and measure-dependent. These findings provide descriptive forensic context but do not establish diagnostic thresholds or causality.