During study of the characteristics of various brain tumors in tissue cultures, it was found that craniopharyngiomas showed a unique growth pattern, different from other brain tumors including glioma. Reports on tissue cultures of craniopharyngioma have been few, probably due to the difficulty of
in vitro propagation. The present report concerns some
in vitro growth patterns of this epithelial tumor.
The biopsied materials were cut into small fragments, about 1-2 mm in diameter, and directly cultured at 37°C in 199 medium containing 10% calf serum, 100 units/ml of penicillin and 100 μg/m
l of dihydrostreptomycin. The medium was changed every three days.
By this simple methods, six tumors out of nine different cases were successfully cultured. Four to five days after being placed in a glass bottle, a monolayer sheet developed from each fragment extending out in eccentric direction from the center.
The cells of the monolayer sheet had a polygonal, rich cytoplasm and an oval nucleus, and were in close contact with each other. In the marginal zone, cells with an extremely large cytoplasm and acellular circular spaces were frequently seen. The free margin of the cell sheets was always sharp without any surrounding scattered cells.
In electron microscopy (plate parallel sectioning method), abundant desmosomes and tonofilaments could be seen as in the original tumors.
On the other hand, in scanning electron microscopy, the surface of this cultured cell was relatively smooth and abundant microvilli were observed.
From these findings, it was concluded that the cultured cells in the monolayer sheets originated mostly in the epithelial cells of craniopharyngioma but not in glial cells of fibrocytes.
The growth rate of the epithelial cell sheets could be estimated by measuring the area of the cell sheets. During the initial ten days, most sheets increased two to five times in area and grew less rapidly for 30 to 40 days until the diameters of the sheets became 5 to 15 mm. Thereafter, they were not enlarge but survived for 150 to 430 days.
In these experiments,
in vitro propagation of cells seemed independent of whether or not the patients received previous irradiation or administration of chemotherapeutic agents such as bleomycin. In addition, it seemed also likely that trypsin digestion was inadequate for long-term proliferation of cells.
Cultured craniopharyngiomas may be useful for studying distinct characteristics from various aspects including screening of the effects of chemotherapeutic agents.
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