Localization and quantitative study of hepatic oval cells in patients with chronic liver diseases: A pathological analysis of 29 liver specimens

OBJECTIVE: To observe the morphological characteristics of oval cells in human chronic liver disease and to determine the relationship between the number of oval cells and the grading and staging of liver fibrosis. METHODS: Oval cells in paraffin-embedded sections of three normal control livers and 29 chronically diseased livers were detected by using histoimmunochemistry. Cells were counted and scored if they satisfied the morphological criteria for oval cells and showed cytoplasmic staining. RESULTS: Oval cells were not observed in normal livers. In chronic liver disease, oval cells were characterized by the presence of an ovoid nucleus, a small-sized cell and scanty cytoplasm, and were located predominantly in the periportal region and fibrous septa. The number of oval cells increased significantly (F = 22.60, P < 0.01) as the staging of fibrosis increased (7 ± 3, 12 ± 3, 25 ± 7, 33 ± 9, and 44 ± 10 in stages 0–4, respectively). There were significant differences between all stages (P < 0.05) except those in stages 0 and 1, and 1 and 2. The number of oval cells was significantly related to the staging of liver fibrosis (r = 0.88, P < 0.01). CONCLUSION: Oval cells are frequently detected in chronically diseased livers. Their presence is related to the staging of fibrosis.