Hepatoblastoma with pure fetal epithelial differentiation in a 10-year-old boy: A rare case report and review of the literature

Abstract

Rationale: Hepatoblastoma is a rare malignant embryonal tumor that only accounts for approximately 1% of all pediatric cancers and mostly develops in children younger than 5 years old. Moreover, the occurrence of hepatoblastoma in adults is extremely rare.

Patient concerns: Herein, we present a rare case of hepatoblastoma with pure epithelial differentiation in a 10-year-old boy.Pathological examination was performed. The tumor was 15 cm × 15 cm in size with clear margins. The cut surface was multiple nodular and grey-yellow. Histologically, the small cuboidal tumor cells were arranged in trabeculae with 2-3 cell layers. The tumor cells had eosinophilic or clear cytoplasm, formed dark and light areas, and were positive for alpha-fetoprotein, CK, CK8/18, CD10, hepatocyte, and GPC3. CD34 staining revealed that the sinusoids were lined by endothelial cells in the tumor tissues. The Ki67 index was approximately 20%.

Diagnoses: Based on these findings, the case was diagnosed as hepatoblastoma with pure fetal epithelial differentiation.

Interventions: The tumor was completely removed.

Outcomes: No recurrence was found 3 months after the operation.

Lessons: Hepatoblastoma with pure epithelial differentiation can also occur in older children. Children rarely notice and report any physical abnormality, and this may be among the primary reasons for the late diagnosis of the tumor. Annual heath checks may be beneficial in the detection of these rare tumors and improvement of patient outcomes.

Figure 1

Gross tumor appearance. The liver surface was smooth and had no obvious disruption (A). The mass was located in the liver and was approximately 15 cm × 15 cm in size with clear margins and thin pseudocapsule (B). The tumor was nodular, and the cut surface was grey-yellow. Scattered foci of hemorrhage can be seen inside the tumor.

Figure 2

Histopathological findings of the tumors. The tumor tissues had dark and light areas (A). Fibrous septum was seen between the tumor cell nodules (B). Some tumor cells invaded the fibrous envelope (C). The small cuboidal tumor cells were arranged in trabeculae with 2–3 cell layers (D). The cell nucleus was small and round with fine nuclear chromatin and a small nucleolus. Some tumor cells contained fine eosinophilic granular cytoplasm that formed the dark areas (E). Tumor cells with clear cytoplasm formed the light areas (F). Bile stasis could be found in few tumor cells (G) and a few areas showed mild atypia (H). Mitosis was less than 1/10 HPF. Focal lymphocyte infiltration was noted in the portal areas of the surrounding liver tissues (H).

Figure 3

Immunostaining findings of the tumors. Weak AFP staining was seen in the tumor cells (A). β-catenin staining was positive in the cell membrane of both the hepatocytes (B) and tumor cells (C). CD10 staining showed a tiny bile canaliculi in the liver tissues (D). CD10 staining was diffuse in the tumor cells (E). CD34 staining was negative in liver tissues (F). CD34 staining was positive in tumor tissues (G), which indicated that the sinusoids were lined by endothelial cells in the tumor tissues. Chromogranin A and synaptophysin were negative in the tumor cells (H, P). CK19 was focally and weakly positive in the tumor cells (K). CK (I), CK8/18 (J), GPC3 (L), and hepatocytes (M) were diffusely positive in the tumor cells. Ki67 index was <1% in the hepatocytes (N) and approximately 20% in the tumor cells (O).