Histology of Some Neoplasms and Non-Neo-plastic Lesions Found in Wild Mice Maintained Under Laboratory Conditions

The histology of some non-neoplastic conditions and spontaneous tumors found in a colony of wild house mice maintained at the National Cancer Institute has been described. Among the neoplasms were reticular neoplasms, a teratoid tumor from the side of the face, several ovarian tumors, a tumor from the foot pad, an osteogenic sarcoma, and a mast cell tumor. Interesting facts about these neoplasms were discussed. The reticular neoplasms were nearly all Type B (Hodgkin's-like lesion of the mouse). Lymphocytic neoplasms were rare, though readily induced by the leukemia-inducing Moloney virus. The teratoma appeared in a 10-week-old mouse and was located away from the midline. It was compared with a previously studied teratoma in the thigh of a noninbred Swiss mouse. The other neoplasms were compared with similar tumors in inbred mice. A non-neoplastic condition, retinal dystrophy, was found in 3 of 11 mice. This condition has been noted in all members of some inbred strains. Another anatomical difference between wild mice and laboratory mice was the absence in the wild mice of a cuboidal epithelial parietal lining of Bowman's capsule. This is a secondary sex characteristic that failed to appear in the wild mice even after testosterone treatment. A few other lesions and anomalies found also in laboratory mice were described.