Hepatic Progenitor Cells in the Form of Ductular Structures within a GIST Liver Metastasis: Supporting a Putative Role in the Hepatic Metastatic Niche.

Introduction: Recent studies have highlighted the presence of hepatic progenitor cells (HPCs) in metastatic liver carcinomas. We provide further evidence of this phenomenon, presenting a case of a gastrointestinal stromal tumour (GIST) liver metastasis with evidence of intra- and peritumoral HPC.

Case description: A 64-year-old man presented with a gastric mass diagnosed as a high-risk KIT-mutated GIST. The patient was treated with imatinib, recurring 5 years later with a liver mass. Liver biopsy disclosed a GIST metastasis, hallmarked by a proliferation of ductular structures without cytological atypia intermingled with the tumour cells, with a CK7/CK19/CD56-positive immunophenotype and rare CD44 positivity. The patient underwent liver resection, and the same ductular structures were present in the tumour interior and at its periphery.

Conclusion: We document for the time the presence of HPC in the form of ductular structures in a GIST liver metastasis, further supporting their role in the liver metastatic niche.