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Published on: March 6, 2018
A prostate fibromyxoid sarcoma with smooth muscle differentiation in a F344xBNF1 rat
L D Berman-Booty1, L M Garzel, V Bergdall
1The Ohio State University, College of Veterinary Medicine, Department of Veterinary Biosciences, Columbus, OH 43210, USA.
Abstract:
This report describes a spontaneous prostate fibromyxoid sarcoma with smooth muscle differentiation in an approximately 136-week-old intact male F344xBNF1 rat on a diet study for 2 weeks. At necropsy, the prostate was markedly distorted and enlarged by a firm white multinodular mass (6.0 × 4.5 × 3.5 cm). Histopathologically, the mass consisted of solid sheets of interlacing mesenchymal spindle cells with indistinct cell borders. Nuclei were separated by variable amounts of hyaline to fibrillar eosinophilic and/or myxomatous material. The extracellular myxomatous material tended to form whorls and stained positively with alcian blue. The mass stained strongly with Masson trichrome and vimentin throughout. Approximately 5% of the neoplastic cells were positive for smooth muscle actin, and none stained for desmin and pancytokeratin. To the authors' knowledge, this fibromyxoid sarcoma with smooth muscle differentiation is the first such described prostatic sarcoma in a rat.
Insights
A rare prostate fibromyxoid sarcoma with smooth muscle features was observed in an aged male rat. This unique tumor presentation in rats offers insights into comparative oncology and potential spontaneous tumor development.
Area of Science:
- Veterinary Pathology
- Oncology
- Comparative Medicine
Background:
- Spontaneous tumors in laboratory animals are crucial for understanding human disease.
- Prostate cancer research often utilizes rodent models.
- Fibromyxoid sarcomas are rare mesenchymal neoplasms.
Observation:
- A spontaneous prostate fibromyxoid sarcoma was identified in a 136-week-old male F344xBNF1 rat.
- The tumor presented as a large, multinodular mass distorting the prostate.
- Histopathology revealed spindle cells embedded in myxomatous and fibrillar material.
Findings:
- The sarcoma exhibited smooth muscle differentiation, with positive staining for smooth muscle actin in approximately 5% of neoplastic cells.
- Alcian blue staining confirmed myxomatous extracellular matrix, and Masson trichrome/vimentin staining indicated mesenchymal origin.
- Absence of desmin and pancytokeratin staining helped differentiate the tumor type.
Implications:
- This case represents the first documented instance of a prostatic fibromyxoid sarcoma with smooth muscle differentiation in a rat.
- The findings contribute to the knowledge base of spontaneous neoplasms in aged rodents.
- This unique tumor model may be valuable for comparative oncology studies and research into prostate cancer development.
