Genetic identification of endoscopic biopsies after unnecessary gastrectomy: Case report and medico-legal evaluation

•Forensic genetic laboratories can analyse samples to verify the genetic correspondence to patient.•Intra-hospital chain of custody of the biopsy samples is of paramount importance.•It is essential to ensure the traceability of samples from collection throughout the work cycle. Forensic genetic laboratories analyse samples included in paraffin to verify the genetic correspondence of histological samples, from living subjects or cadavers, in cases where there is a suspicion of contamination of samples with tissues of other patients. A case of a man subjected to a gastrectomy as a result of a histological diagnosis of gastric adenocarcinoma after endoscopic biopsies is reported. The microscopic analysis on the gastric tissue after the gastrectomy excluded the presence of cancer. Having suspected a diagnostic error, a microscopic revision of the biopsies was performed and confirmed the presence of cancer cells but led to a hypothesis that there had been contamination with foreign intestinal tissue. The genetic analysis performed on various pieces of tissue, despite the reduced amount of biological material, succeeded in identifying the presence of two incomplete genetic profiles, one of which belonged to a subject of the opposite sex. The case raised many questions about the process of setting up histological specimens. Even though it is impossible to identify the healthcare professionals responsible for contamination, the organizational error during the management of biopsies has significantly affected the clinical case of the patient, who underwent a gastrectomy for cancer that was not present. This case is not simply an example of diagnostic error and related unnecessary surgery, but it has raised some doubts about patient management and it has led us to some medical-legal cause for reflection in the field of professional liability.