Observation of psammoma bodies in cultured meningiomas: analysis of three-dimensional structure using scanning and transmission electron microscopy
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T Tsuchida1, M Matsumoto, Y Shirayama
1Department of Neurosurgery, Kansai Medical University, Moriguchi, Osaka, Japan.
Abstract:
In contrast to the inner structure, three-dimensional structure of psammona bodies in meningiomas is not well defined. This study examined three cultured meningiomas, in which surface observation of psammoma bodies might be easier than in the tumor tissues since influence of interposing connective tissue is minimized in tissue culture. Early culture revealed that psammoma bodies with frank calcification were suspended in the tissue culture medium, and so were they collected, centrifuged, and then processed for electron microscopy. Ultrastructurally, psammoma bodies were mostly spherical in shape and composed of a core of dense calcification and surrounding collagen fiber bundles. Apart from psammoma bodies, round bodies with concentric lamination like a transversely cut onion were frequently noted by light microscopy. These bodies were composed mainly of tangles of collagen fibers emerged from surrounding tumor cell processes. The results suggest that psammoma bodies in meningiomas arise in part from meningothelial whorls due to collagen production by tumor cells followed by obliteration and disappearance of tumor cell processes, although some of the alternative pathways for psammoma body formation proposed by other investigators cannot be ruled out by this study.
Insights
Psammona bodies in meningiomas, often poorly understood, are primarily composed of calcified cores and collagen fibers. This study suggests they originate from meningothelial whorls and tumor cell collagen production.
Area of Science:
- Neurosurgery
- Oncology
- Cell Biology
Background:
- The three-dimensional structure of psammoma bodies in meningiomas is not well-defined.
- Tissue culture offers a simplified model for observing psammoma bodies by minimizing connective tissue interference.
Purpose of the Study:
- To investigate the ultrastructure and formation of psammoma bodies in cultured meningiomas.
- To elucidate the origin and composition of psammoma bodies in meningioma tissues.
Main Methods:
- Culturing three meningioma samples to facilitate surface observation of psammoma bodies.
- Collecting, centrifuging, and processing psammoma bodies from tissue culture medium for electron microscopy.
- Utilizing light microscopy to identify and characterize round bodies with concentric lamination.
Main Results:
- Psammoma bodies, often spherical, consist of a dense calcified core surrounded by collagen fiber bundles.
- Round bodies with concentric lamellar structures, resembling onions, were observed and identified as tangles of collagen fibers from tumor cell processes.
- Psammoma bodies were found suspended in the tissue culture medium, indicating their release from the tumor matrix.
Conclusions:
- Psammoma bodies in meningiomas likely originate partly from meningothelial whorls through tumor cell collagen production.
- The formation process involves the obliteration and disappearance of tumor cell processes.
- Alternative pathways for psammoma body formation cannot be definitively excluded by this study.