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Intraabdominal lymphangiosarcoma in a Fischer-344 rat
K Takahashi1, N Nakashima, M Kuwahara
1Department of Veterinary Pathology, Nippon Veterinary and Animal Science University, Tokyo, Japan.
Toxicologic Pathology
|July 1, 1997
Summary
This study investigated an abdominal sarcoma in a rat, identifying it as a lymphatic endothelial tumor through advanced microscopy and immunohistochemistry. The findings differentiate it from blood vessel tumors, offering insights into rare sarcoma classifications.
Area of Science:
- Oncology
- Veterinary Pathology
- Cell Biology
Background:
- A rare sarcoma was identified in the abdominal cavity of an aged Fischer-344 rat.
- The tumor presented as a white-yellow soft mass on the lumbosacral vertebrae, causing compression of adjacent organs.
Observation:
- The tumor comprised spindle-shaped cells within a myxoid matrix, with minimal reticulin and collagen fibers.
- Cells exhibited a loose storiform pattern and formed ovoid or slit-like spaces via cell processes.
Findings:
- Immunohistochemistry revealed strong vimentin positivity and negativity for keratin, macrophage ED1 antigen, alpha-smooth muscle actin, Factor VIII-related antigen, and S100 protein.
- Electron microscopy showed endothelial differentiation, including luminal spaces, micropinocytotic vesicles, desmosomes, and structures resembling Weibel-Palade bodies.
- Absence of a definitive basement lamina and presence of extracellular anchoring filaments further supported endothelial origin.
Implications:
- The tumor was definitively characterized as being of lymphatic vessel endothelial origin.
- These findings contribute to the understanding of soft tissue sarcomas and their specific cell lineage.
- This detailed pathological analysis aids in the differential diagnosis of rare mesenchymal tumors in animal models.