1, causes of disease
Chronic urinary tract infection is the main etiology of bladder squamous cell carcinoma, in90%~93% of bladder squamous cell carcinoma patients' urine can have pus cells and leukocytes for a long time. Chronic inflammation stimulation can cause squamous metaplasia of transitional epithelium, intercellular change, and carcinogenesis. Some believe that after infection, some bacteria convert nitrates into nitrites and nitrosamines with carcinogenic effects, and then cause cancer. Stimulation of foreign bodies such as bladder calculi and catheters is also an important etiology of squamous cell carcinoma. The incidence rate of bladder calculi combined with squamous cell carcinoma is 0.074%~9.9%(Sarma,1970; Bessette,1974) However, the incidence rate of squamous cell carcinoma combined with calculi is as high as2.77%~47%(Zhu Liangchun,1980; Zhang Sihao,1987) that long-term stimulation of calculi can cause hyperplasia of tissue cells and carcinogenesis. Long-term indwelling catheter chronic stimulation can also cause the occurrence of cancer. Kaufman(1977) reported62example, spinal cord injury patients, indwelling catheter10years80% have bladder squamous metaplasia6months to10years42% have bladder squamous metaplasia, while those who have not placed a catheter have a bladder squamous metaplasia rate of20%. Indwelling catheter10years25In the example5En example, squamous cell carcinoma occurs, accompanied by diffuse inflammation, squamous metaplasia, and bladder in situ carcinoma. It indicates that chronic bladder inflammation, calculi, foreign bodies, and others are interrelated and often coexist, all of which can cause squamous metaplasia of transitional bladder epithelium, intercellular change, atypical hyperplasia, and lead to carcinogenesis. In Egypt, Africa, and the Middle East, where schistosomiasis is prevalent, the bladder wall of bladder cancer70% can be found schistosome eggs, so it is considered that Schistosoma haematobium infection is one of the causes of squamous cell carcinoma of the bladder, but its carcinogenic mechanism is not yet clear, bladder mucosal leukoplakia and other lesions can further develop into tumors under certain factors.
2、Pathogenesis
Squamous cell carcinoma of the bladder often appears as flat or slightly elevated at first, infiltrative growth, showing solid mass, ulcerative or papillary. It is usually solitary, but can also be multiple. Pathological examination shows pure squamous cell carcinoma is more common, and mixed carcinoma with components such as transitional cell carcinoma and adenocarcinoma accounts for1/3. The histological characteristics are the appearance of keratinocytes, large squamous cell tumors present in a patchy, irregular arrangement, with keratinocytes arranged in a concentric pattern - keratin pearls. According to the degree of differentiation of squamous cells, it can be divided into Ⅳ levels, level Ⅰ: highly differentiated cells, very similar to normal or metaplastic squamous epithelial cells, with keratin pearls formation, mild nucleolar abnormalities; level Ⅱ: the tumor is solid, with extensive keratinization and keratin pearl formation; level Ⅲ: keratin is limited to individual cells and occasionally keratin pearls; level Ⅳ: has large transparent cells, rare low differentiated squamous cells. Small cell squamous cell carcinoma, cells are poorly differentiated, similar to the reed cell carcinoma of the lung, with typical squamous cell carcinoma pearls. Squamous cell carcinoma caused by schistosomiasis, often visible to have two-nucleus giant cells.