Clinicopathological Characteristics of Neutrophil-Rich Hepatocellular Carcinoma: An Uncommon Subtype of Primary Liver Cancer.

Introduction. Neutrophil-rich hepatocellular carcinoma (HCC) is an extremely uncommon subtype of HCC with an overall incidence of <1%. Neutrophil-rich HCC shows poor cellular differentiation and sarcomatoid transformation in most patients. There is prominent neutrophilic inflammatory cell infiltration in the tumor. These tumors are associated with poor prognosis, high rate of recurrence, and metastasis. Methods. Herein, we investigated 4 patients with neutrophil-rich HCC reported at our center. Clinical, radiological, and pathological findings were reviewed. Immunophenotypic characterization of the tumors were done. Granulocyte colony-stimulating factor (G-CSF), programmed cell death ligand 1 (PD-L1), and mismatch repair immunostains were performed in all 4 tumors. Results. We report 4 neutrophil-rich HCCs in 3 male patients and one female patient with an age range of 43 to 64 years. Three underwent living donor liver transplantation and one underwent right hepatectomy. Tumor measured 0.5 cm to 12 cm in maximum dimension. Histologically, tumors demonstrated moderate to marked cellular pleomorphism. Spindle cell transformation was noted in 3 tumors. Three tumors showed vascular invasion, and one tumor showed bile duct invasion. Immunopositivity for Hep Par-1, arginase-1, and glypican-3 was present in all tumors. Tumors also expressed stemness markers including KRT19 and EpCAM. Cytoplasmic positivity for G-CSF and immunoexpression of PD-L1 was demonstrated. We also report proficient mismatch repair by immunohistochemistry in all tumors. Conclusion. Neutrophil-rich HCC is an aggressive primary liver cancer which demonstrates stemness-related features. Programmed cell death ligand 1 expression in tumor cells suggests distinct immunogenic features and potential role of anti-PD-L1 therapies in inoperable disease.