Childhood astrocytoma is a disease in which benign (noncancer) or malignant (cancer) cells form in the tissues of the brain.
Astrocytomas are tumors that start in star-shaped brain cells called astrocytes. An astrocyte is a type of glial cell. Glial cells hold nerve cells in place, bring food and oxygen to them, and help protect them from disease, such as infection. Gliomas are tumors that form from glial cells. An astrocytoma is a type of glioma.
Astrocytoma is the most common type of glioma...
Small cells that reflect neither epithelial nor stromal differentiation.
Embryonal epithelial cells resembling the liver epithelium at 6 to 8 weeks of gestation.
Well-differentiated fetal hepatocytes morphologically indistinguishable from normal fetal liver cells.
Most often the tumor consists of a mixture of epithelial hepatocyte precursors. About 20% of tumors have stromal derivatives such as osteoid, chondroid, and rhabdoid elements. Occasionally neuronal, melanocytic, squamous, and enteroendocrine elements are found. Two histologic subtypes have clinical relevance: pure fetal histology throughout the tumor and foci of small cell undifferentiated cells.
Pure fetal histology hepatoblastoma
Analysis of patients with initially resected hepatoblastoma tumors (prior to receiving chemotherapy) has suggested that those patients with pure fetal histology tumors have a better prognosis than those having an admixture of more primitive and rapidly dividing embryonal components or other undifferentiated tissues. In a study of patients with hepatoblastoma and pure fetal histology tumors, there was a 100% survival rate for patients who received four doses of single-agent doxorubicin. This suggested that patients with pure fetal histology tumors might not need chemotherapy after complete resection of a stage I tumor.[2,3] In the Children's Oncology Group (COG) study COG-P9645, 16 patients with stage I pure fetal histology hepatoblastoma with two or fewer mitoses per 10 high power fields were not treated with chemotherapy. Their retrospective PRETEXT stages were stage I (n = 4), stage II (n = 6), and stage III (n = 2). Survival was 100% with no chemotherapy given. All 16 patients entered on this study were alive with no evidence of disease at a median follow-up of 4.9 years (range, 9 months to 9.2 years). Thus, complete resection of a pure fetal hepatoblastoma may preclude the need for chemotherapy.
Small cell undifferentiated hepatoblastoma
Small cell undifferentiated hepatoblastoma is an uncommon hepatoblastoma variant that represents a few percent of all hepatoblastomas. It tends to occur at a younger age (6-10 months) compared with other cases of hepatoblastoma [5,6] and is associated with AFP normal for age at presentation.[5,7]