Fat embolism: a systematic review to facilitate the development of standardised procedures in pathology.

Fat embolism (FE) is a historically recognised but still actively researched topic in forensic pathology. Several aspects remain not fully elucidated, such as its aetiopathogenesis, its causal role in death determination, the impact of interfering factors (e.g. cardiopulmonary resuscitation or other medical procedures) and both qualitative and quantitative diagnostic methodologies in clinical and forensic contexts. These issues are further underscored by the potential involvement of FE in the causal determination of non-traumatic deaths, which often raises questions of professional liability. The present study aims to provide a comprehensive and up-to-date overview of the most recent scientific evidence relevant to forensic pathology. Our systematic research has included 58 articles from 1990 to the present on the topic of FE and fat embolism syndrome (FES). From these articles, we identified 45 case reports, from which the authors' descriptions were extracted to provide information on individual cases and the operational methods of forensic pathologists. Additionally, 21 experimental studies were identified, and their key findings have been summarised narratively. It has emerged that both traumatic and non-traumatic cases are frequently reported in the forensic context, with orthopaedic and cosmetic surgery being among the highest-risk specialities. Experimental studies have re-evaluated the role of a patent foramen ovale in the pathogenesis of FE, as well as the impact of cardiopulmonary resuscitation in causing FE severe enough to result in death. Additionally, there are new findings regarding diagnostic techniques, including radiological and immunohistological methods; however, they have not yet fully bridged the reliability gap compared to an accurate autopsy-histological evaluation. The major critical points that emerged include the lack of complete and detailed information on premortem clinical conditions, the underutilisation of grading systems and the methodological heterogeneity applied, resulting in considerable variability regarding the organs studied histologically and the diagnostic techniques used. Despite the limitations associated with the analysis of case reports and the heterogeneity of included experimental studies, we believe that this study can provide a comprehensive overview of the FE topic. It furnishes pathologists with an updated overview useful for clinical practice and guiding future research trends, as well as facilitating the development of standardised procedures.