Journal of Toxicologic Pathology
Online ISSN : 1881-915X
Print ISSN : 0914-9198
Case Reports
Malignant mast cell tumor of the thymus in an Royal College of Surgeons (RCS) rat
Yui TerayamaTetsuro MatsuuraKiyokazu Ozaki
Author information
JOURNALS FREE ACCESS

2017 Volume 30 Issue 1 Pages 63-67

Details
Abstract

A 152-week-old male Royal College of Surgeons (RCS) rat kept as a non-treated animal in a long-term animal study presented with a soft mass in the anterior mediastinum, which adhered to the pleura of the lung. Histopathologically, the mass mainly consisted of round to short spindle-shaped tumor cells that had infiltrated through the hyperplastic thymic tissue. The tumor cells were arranged in loose to dense sheets. Nuclei were moderate in size and round to spindle-shaped, with small nucleoli. Almost all tumor cells exhibited abundant eosinophilic cytoplasm, including eosinophilic granules of a range of sizes. The granules of tumor cells exhibited metachromasia with toluidine blue stain and were positive for c-kit and mast cell protease II. These findings indicate that the tumor described here represents a rare case of spontaneous malignant mast cell tumor with thymic epithelial hyperplasia.

Information related to the author
© 2017 The Japanese Society of Toxicologic Pathology
Previous article Next article
feedback
Top