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Pseudomalignant spindle cell proliferations of the urinary bladder
L Lundgren1, F Aldenborg, L Angervall
1Department of Pathology, Sahlgren Hospital, University of Göteborg, Sweden.
Human Pathology
|February 1, 1994
Summary
This study analyzes pseudomalignant spindle cell lesions in the urinary bladder, identifying fibroblast and myofibroblast characteristics. Awareness of these diverse immunophenotypic features is crucial to prevent misdiagnosis of sarcomas or carcinomas.
Area of Science:
- Uropathology
- Cell Biology
- Oncology
Background:
- Spindle cell lesions of the urinary bladder can be challenging to diagnose.
- Distinguishing benign proliferations from malignant sarcomas or carcinomas is critical for patient management.
Purpose of the Study:
- To characterize the histopathological and immunophenotypic features of polypoid, nonrecurrent, pseudomalignant spindle cell proliferations of the urinary bladder.
- To highlight the importance of recognizing these lesions to avoid misdiagnosis.
Main Methods:
- Analysis of twelve cases of urinary bladder spindle cell lesions.
- Electron microscopy to assess cellular ultrastructure.
- Immunohistochemistry for fibroblast, myofibroblast, muscle, epithelial, and other markers.
- Flow cytometry for DNA analysis.
Main Results:
- Lesions showed spindle- or strap-shaped cells with fibroblast/myofibroblast features on electron microscopy.
- Immunoreactivity for vimentin (100%), alpha-smooth muscle actin (6/12), cytokeratins (5/12), and CD 34 (1/12).
- No significant immunoreactivity for desmin, S-100, or endothelial markers. Ki-67 and PCNA showed proliferation in up to 30% of cells.
- DNA analysis revealed diploid or hyperdiploid stem cell lines.
Conclusions:
- Pseudomalignant spindle cell proliferations of the urinary bladder exhibit diverse immunophenotypic characteristics.
- Understanding these features is essential for accurate diagnosis, differentiating them from malignant spindle cell tumors like leiomyosarcoma, embryonal rhabdomyosarcoma, or spindle cell carcinoma.