The issue of the microplastics in the medico-legal context: might histopathology and immunohistochemistry say something?

In recent years, increasing public health interest has directed toward study of micro- and nanoplastics and their potential toxic effects on human health. The search for microplastics is also of major importance in fields of forensic science, for example, in cases of corpses lingering in salt water. Starting from a drowning case, we carried out the search for microplastics in lung parenchyma samples taken at autopsy. Although analysis of microplastics should preferably be conduct by chemical, spectrophotometric, and scanning electron microscope techniques, we attempted to analyze a case of drowning using light microscopy and special histochemical staining to isolate particles compatible with microplastics in a human lung sample. Staining in hematoxylin-eosin and with PAS, Grocott, Masson’s trichrome, and Alcian blue allowed us to demonstrate the relative weakness of particle staining, allowing us to hypothesize concretely that these are microplastic particles. In the medico-legal field, when chemical and physical techniques cannot be use because the organic material has been fixed in formaldehyde and embedded in paraffin (FFPE), light microscopy accompanied by special histochemical staining can play an indicative role. Light microscopic observation of the preparations stained with routine hematoxylin-eosin (H&E) staining revealed microscopic particles on the order of 100/200 microns within the pulmonary alveoli (alveolar cavities), which reacted weakly with the staining. This result was also arrived at by histochemical staining with Masson and Grocott trichrome, which was negative/weak for the particles of our interest, while it was positive for nearby alveolar structures. The problem of microplastics is highly topical, both in terms of environmental health and human health. Research in this area is yielding great results, enabling the discovery and study of numerous pathologies associated with the presence of microplastics in the human body. It is therefore crucial to establish the potential damage that micro/nano plastics pollution can actually cause. In the forensic field, the finding of microplastics represents a major issue. The finding of these particles in the lung of a cadaver found in water, and the thorough histological analysis performed, is the subject of this paper. Our paper aims to investigate the role of traditional histology in the search for microplastics in forensic medicine.