What Is an Astroblastoma?

Astroblastoma is the most malignant astrocytic tumor, which is composed of poorly differentiated tumorous astrocytic cells. Histological features include cell polymorphism, nuclear atypicalness, high mitotic activity, vascular thrombosis, microvascular hyperplasia, and necrosis. Glioblastoma mainly affects adults and occurs in the cerebral hemisphere. Glioblastoma can develop from WHO grade II of diffuse astrocytoma (secondary glioblastoma), but more commonly a primary glioblastoma with a short clinical history and no low premalignant lesions Cell tumor. ^[1]

Astroblastoma

Astroblastoma incidence

Astroblastoma is the best tumor in the brain, accounting for 12% to 15% of intracranial tumors and 50% to 60% of astrocytomas. In most European and North American countries, 2-3 new cases per 100,000 are added each year.

Astroblastoma pathology

1. Macroscopic view: The tumor is limited, soft and fragile, and the cut surface is red or gray-red, showing invasive growth, but the tumor boundary is visible to the naked eye. Most tumors are parenchymal, with cystic changes, small lesions of bleeding and necrosis, and rarely calcification.

2. Light microscope: under light microscope, the tissue morphology is close to that of glioblastoma, but the polymorphism is not outstanding. Tumor cells are abundant, and their main constituent cells are astroblasts. Tumor cells are arranged around blood vessels, showing pseudovascular chrysanthemum-like or radial arrangements around the blood vessels. The blood vessels are rich, the wall thickness is different, and the cells are often glassy. Multinucleated cells, astrocytes and glioblasts are also common in tumors. Tumor tissue away from blood vessels is often present.

Electron microscopy and tumor markers are characteristic of astrocytomas. The clinical features of astroblastoma are between astrocytoma and glioblastoma. It grows faster than astrocytomas, with an average disease duration of 1 to 20 months. Cerebellar astroblastoma has a shorter disease course than cerebral astroblastoma because it causes obstructive hydrocephalus. Symptoms include increased intracranial pressure and focal brain dysfunction, which are not significantly different from other intracranial tumors. It is often difficult to distinguish from astrocytoma before surgery. Treatment is similar to astrocytoma, but the prognosis is poor.

Astroblastoma symptoms

Clinical manifestations in adults often have epilepsy first, gradually appear paralysis, aphasia, mental changes, and then increase intracranial pressure. Most children first show increased intracranial pressure.

Astroblastoma signs

Except for diffuse astrocytoma or anaplastic astrocytoma secondary to WHO class ll, the history is usually short (more than half <3 months). Often manifested as non-specific neurological dysfunction, such as epilepsy, headache, and personality changes. The most dangerous of these is the rapid increase in intracranial pressure. Neuroimaging CT examinations typically show irregular intracranial lesions, with low-density necrosis areas in the center after enhancement, and ring-shaped enhanced shadows in the periphery. On the MRI T1W image, the ring-shaped enhanced shadow around the tumor is not the outer edge of the tumor, but the area of vigorous cell proliferation and high-density blood vessels. Infiltrated glioma cells can be strengthened within and outside the tumor's periphery 2cm. On T2W, the ring-shaped enhancement zone is wider, the border is unclear, and it overlaps with angioedema. In PET, local glucose consumption is closely related to tumor cell composition and survival.

Astroblastoma test

Skull X-ray plain film: mainly separation of cranial sutures and increased finger pressure marks. The tumors on the surface of the cerebellar hemisphere showed thinning and erosion of the occipital squamous scale on the affected side. In this group, 4.3% had tumor calcified plaques.

Ventricular angiography: In addition to the symmetrical expansion of the lateral ventricle and the third ventricle, the forward deflection of the aqueduct and the displacement of the fourth ventricle to the healthy side are characteristics of cerebellar hemisphere tumors.

CT examination: low density shadows in the cerebellar hemisphere or midline area can be seen. Astrocytoma grade I can be strengthened without injection, and grade II to III can be strengthened. Some of them show multiple low-density in high density (ie, the sac is inside the tumor), and some have high-density tumor nodules at the edge of the low-density area (ie, the tumor is in the sac). This sign often helps to treat the qualitative.