The author had succeeded in preparing large section specimens including the eye ball, upper jawand other surrounding soft tissues.The materials from 8 cases with maxillary squamous cell carcinoma were obtained en bloc.The observation of the specimens was made by chiefly macro skopicaly and sometimes with 6-1Cfold magnifier.The results obtained were as follows:1) In stained large section specimens, the relationship between tumors and bones or neighboring tissues and hence, the, growth and spreading of cancer were evidently demonstrated.2) There were 2 types of the destructive processes of bony walls of maxillary sinus with tumor, the expansive and the infiltrative bone destruction. The former is caused by compression due to the expansive growth of tumor without direct contact with bone, while the latter is found at the bonewall in direct contact with tumor. Then the tumor invades marrow cavity.3) In the apical portion of tumor having completely destroyed bone, the capsule-like layers were often observed. The layers are formed chiefly of the thickened periostium accompanied with the proliferation of stroma in fat tissue. However at the muscle layers in direct contat with tumor they were generally unrecognized.4) And there are two kinds of types in spreading manner of maxillary sinus cancer, one is the spreading that the carcinoma having expansively destroyed bone invades the soft tissues surrounding the maxillary bone and the formation of the capsule-like layers around tumor is prominent. The other, spreading that carcinoma destroys infiltratively bone and in the apical portion of tumor the formation of the capsule-like layer is not evident.5) The expansively spreading form was observed in 4 of the 8 cases, and the infiltratively spreading form in the others. After operation the prognosis of the former is relatively good, and that of the latter is poor.