Suspected Microplastic-Like Particles Recovered From Paired Human Small Intestine and Large Intestine Specimens: An Exploratory Post-mortem Study.

Background Evidence regarding suspected microplastic (MP)-like particles in human intestinal specimens remains limited. This study evaluated their occurrence and anatomical distribution in paired small and large intestinal specimens. Methodology This exploratory post-mortem study included 55 adults examined between March 2022 and December 2025. Intestinal specimens were processed using hydrogen peroxide digestion, glass-fiber filtration, Nile Red staining, fluorescence imaging, and ImageJ-based quantification. These screening methods did not provide polymer-specific identification. Histopathological changes were assessed, and clinical and laboratory data were extracted from medical records. Results Suspected MP-like particles were recovered from at least one intestinal specimen in 28 (50.9%) individuals. Detection was numerically more frequent in the large than in small intestinal specimens (38.2% vs. 21.8%), although the paired difference was not statistically significant. Urban residence was less frequent among individuals with screening-positive specimens (p = 0.026). No significant associations were identified for the other clinical and laboratory variables. In exploratory unadjusted analyses, screening positivity co-occurred more frequently with histological inflammation. However, small contingency tables, clinical heterogeneity, and potential confounding preclude causal interpretation. Necrosis was uncommon, and fibrosis was absent. Conclusions Suspected MP-like particles were recovered using a non-polymer-specific screening workflow. Their co-occurrence with non-specific inflammation is hypothesis-generating and requires confirmation using polymer-specific methods and rigorous contamination controls.