The fine structure of astrocytomas

Astrocytomas are the most common intra axial tumor of the central vervous system. They represent a clinically diverse group of neoplasms were some of them are benign, some start as benign tumor and develop anaplastic features and some show a progressive development of malignancy.

Completing the classical histopathological descriptions of astrosytomas we report the ultra structural findings of this group of tumors.

Studying these tumors using the electron microscope we report:

a) numerous astrocytic processes forming a dense net pattern witch also surrounds vessels.

b) the innumerable glial filaments forming intracytoplasmic bundles.

c) changes in mitochondria.

d) astrocytes contained membrane bound autophagic vacuoles and presence of broken microtubules.

e) fragmentation of the cisten of the smooth endoplasmic reticulum and the Golgi apparatus.

f) rough distribution of the chromatin in the nucleus

g) invaginations inside the nucleus.

Grading of astrocytomas has been a subject of many arguments resulting in the existence of numerous grading systems and the lack of a universally accepted grading scheme. Although, electron microscopic examination is a expensive and not rutine diagnostic approach, detecting ultrastructural criteria of anaplasia can confirm the diagnoses or lead to the accurate recognition of an entity.

Key words: astrocytomas, electron microscopy, brain tumors.