Histological Type and Morbidity of Spontaneous Lung Tumor in KunmingMice

[Abstract] Objective To study on the morbidity,morphology,histological type and biological characteristics of spontaneous lung tumor in Kunming mice. Methods A total of 1000 Kunming mice propagated in Changchun Institute of Biological Products were dissected, and the routine patholoical sections were prepared from the lobes of lung, trachea, pulmongical hilar lymph nodes, hearts, livers, spleens and brains of them and used for histopathological examination. Results Fifty - six cases of lung lump were observed during dissection. Thirty - five cases were diagnosed as lung tumor, and the rest 21 cases as nontumorous pathological change or metastatic tumor.The morbidity rate of spontaneous primary lung tumor was 3.5% . Most of the tumors were round and nodular,and a small proportion of them were oval,fungoid,platode,large biock or slightly square. Of the 35 cases of lung tumor, 32 were adenocarcinoma of lung, and the rest 3 were benign papillary adenoma. The 32 cases consisted of 20 cases of papillary, 5 cases of acinar, 6 cases of mixed type and 1 case of mucous papillary adenocarcinoma. Of the 35 mice with lung tumor,20 were male,and the rest 15 were female.The sex ratio of them was 4:3. The morbidity of lung tumor in the mice aged 10 - 14 months and those at the 8th to 12th litters increased significantly. Conclusion The morbidity of spontaneous lung showed no signifcant difference in the mice of different sexes. However, it increased as the increasing ages of the mice. A mouse should not give birth to more than 7 litters.