Overview
Tumor of bladder is the most common tumor in the genitourinary tract, most of which originate from epithelial tissue, and more than 90% of them are metastatic epithelial tumors. In recent years, there is an increasing trend of incidence. The incidence in men is 3 to 4 times higher than that in women, and the highest incidence is 58% in the age group of 51 to 70 years.
I. Etiology
1.Chemical carcinogenic substances.
Occupational personnel with long-term exposure to certain carcinogenic substances, such as dyestuff, textile, leather, rubber, plastic, paint, printing, etc., are at increased risk of bladder cancer. The carcinogenic substances are intermediates in dyes such as l-naphthylamine, 2-naphthylamine and allied amines, and the antioxidant 4-aminobase of rubber and plastic also have carcinogenic effect on bladder. The latency period of cancer after contact with carcinogenic substances is 5 to 50 years, mostly around 20 years.
2.The relationship between abnormal endogenous tryptophan metabolism and bladder tumor, many bladder cancer patients have no obvious history of exposure to chemical carcinogenic substances, which may be related to abnormal tryptophan metabolism in the body. The accumulation of normal metabolites of tryptophan, the intermediate metabolites are all o-hydroxyaminophen substances and can cause bladder tumors in mice.
3, smoking in recent years found that there is a significant relationship between smoke and bladder tumors, smokers than non-smoking men bladder cancer incidence is 4 times higher; smoking may cause cancer and cigarettes contain a variety of aromatic amine derivatives of carcinogenic substances.
4, artificial sweeteners such as saccharin have bladder carcinogenic effects, in addition to long-term use of analgesics finasteride can also increase the risk of bladder tumors. Chronic bladder infection and irritation as well as the drug cyclophosphamide can also cause bladder cancer.
Pathological changes of bladder tumors can be divided into two categories, namely tumors from epithelial and non-epithelial tissues.
I. Tumors occurring from epithelial tissues, mainly including metastatic epithelial tumors, adenocarcinoma and squamous epithelial carcinoma, 98% of bladder tumors come from epithelial tissues, of which metastatic epithelial tumors account for 95%.
1.Migratory epithelial tumors.
They mainly include carcinoma in situ, papilloma, papillary carcinoma and solid carcinoma. The latter two can appear in one tumor at the same time and are called papillary solid carcinoma. This classification facilitates clinical application, but in terms of tumor biological behavior, it is very controversial whether they are successive development of different stages of one disease or appear alone at the beginning.
(1) Carcinoma in situ is a specific metastatic epithelial tumor that starts out confined within the metastatic epithelium, forming slightly raised villi-like red patches that do not invade the basement membrane, but the cells are poorly differentiated and the intercellular adhesion is lost, so the cells are easily shed and easily examined from the urine. The natural course of carcinoma in situ is unpredictable, some of them are asymptomatic for a long time and do not appear to infiltrate, while others develop rapidly. It usually takes 1 to 5 years for carcinoma in situ to develop into infiltrating carcinoma, and some of them take up to 20 years.
(2) Papilloma is a benign tumor histologically seen to originate from the normal bladder mucosa and protrude into the bladder like watercress with a slender tip, in which a clear central bundle of fibrous tissue and blood vessels is visible. The recurrence rate of papilloma is 60% within 5 years, of which 48.6% recur more than twice. Regular postoperative cystoscopic follow-up is necessary.
(3) Papillary carcinoma is the most common among metastatic epithelial tumors. Pathologically, the papillae are thick and short fused, the surface of the tumor is not polished, necrosis or calcium salt deposits, and the base of the tumor is wide or the tip is thick and short. Sometimes the papillary carcinoma may be as long as a small fist, but still retains a tip and has no infiltration to other parts. Although this shape is uncommon, attention should be paid to avoid unnecessary total cystectomy.
(4) Solid carcinoma is the most malignant among metastatic epithelial tumors, with uneven surface, no obvious papilla formation, ulcers on the surface of the tumor, with elevated edges of the ulcers and nodular surface, and early infiltration to the depth, so it is also called infiltrative cancer.
2.Adenocarcinoma.
Also known as adenoid carcinoma, mucinous adenocarcinoma or indolent cell carcinoma, it is a relatively rare bladder tumor. Adenocarcinoma is mostly found in the bladder triangle, the lateral wall and the top of the bladder. Adenocarcinoma of the bladder triangle often originates from adenoid cystitis or cystic cystitis. Glandular and cystic cystitis are associated with the development of the cloaca because during the embryonic period the cloaca is separated into the genitourinary sinus and the rectum. Chronic irritation can also cause glandular metaplasia of the metastatic epithelium. Adenocarcinomas located at the top of the bladder originate from the remnants of the umbilical ureter, are hidden, and are often advanced by the time symptoms appear. Metastatic adenocarcinoma can also appear in the bladder, which can come from the rectum, stomach, endometrium, ovary, breast or prostate, but of course it is very rare.
3. Squamous cell carcinoma of the bladder.
It is also uncommon, accounting for 0.58% to 5.55% in 12 reports of bladder tumors in recent years in China. The metastatic epithelium of the bladder can be transformed into squamous epithelium under various stimuli. There are reports that focal squamous epithelial metaplasia can reach 60%, but it is still mainly a metastatic cell carcinoma. There are many reports of bladder cancer associated with bladder stones in China. Generally speaking, squamous cell carcinoma of the bladder is more malignant than metastatic epithelial carcinoma, with fast development, deep infiltration and poor prognosis.
Second, non-epithelial bladder tumors.
They are tumors from mesenchymal tissue, accounting for less than 20% of all bladder tumors. They include hemangioma, lymphangioleioma, malignant lymphoma, smooth muscle tumor or sarcoma, myoblastoma, rhabdomyosarcoma, pheochromocytoma, malignant melanoma, polyp, carcinoid tumor, plasma cell tumor, fibroma, fibrosarcoma, mucinous liposarcoma, carcinosarcoma, histiocytoma, nerve sheath tumor, chondrosarcoma, malignant teratoma and dermatofibroma. Among them, malignant lymphoma may be a systemic disease; hemangioma may occur simultaneously and be connected with hemangioma of adjacent organs, making surgery difficult. Transverse myxosarcoma originates from the bladder triangle or submucosa of the bladder. On the one hand, it expands to the submucosa, and on the other hand, the tumor pushes against the bladder mucosa and grows into the bladder, forming small lobulated masses that look like grape bunches, so it is also called grape sarcoma. Microscopically, transverse muscle-like fibers and naive embryonic mesenchymal cells can be seen.
The malignancy degree of bladder tumor is expressed by “grade” (grade), the earliest method is Brqder4, but it is difficult to use accurately, and it is difficult to distinguish grade II and grade III. In recent years, the three-level method is mostly used.
Grade I: The tumor is well differentiated, with more than 7 layers of migrating epithelium, and its structure and nuclear anomalies are slightly different from normal, and nuclear division is occasionally seen.
Grade 2: In addition to epithelial thickening, cell polarity disappeared moderate nuclear anisotropy appeared and nuclear division was common.
Grade III: Undifferentiated form with no resemblance to normal epithelium, nuclear divisions are common, this grade is equivalent to grade III and II of the roder method.
Some people tend to juxtapose papilloma with grade I papillary carcinoma, while others strictly separate papilloma. We advocate the latter because a portion of papilloma can be treated without recurrence for life, or with recurrence and always remain as papilloma. Generally speaking, the grade is proportional to the infiltrative nature, the possibility of developing infiltrative bladder cancer is 10% for grade I, 50% for grade II and 80% for grade III.
4.Metastatic pathways of bladder tumor
1.Lymphatic metastasis is the most common route. Bladder cancer can metastasize to the internal iliac, external iliac, and closed-hole lymph node groups, or to the common iliac lymph nodes. It has been pointed out that internal iliac and foramen ovale lymph nodes are the first lymph nodes of bladder cancer metastasis.
2. Hematogenous metastasis via blood is commonly seen in advanced cases, most often in the liver, followed by lung and bone. Skin, adrenal gland, kidney, pancreas, heart, testis, salivary gland, ovary, muscle and gastrointestinal have been reported, but they all account for a minority.
3.Direct spread is often seen in the prostate or posterior urethra. Bladder cancer may extend outside the bladder and adhere to the pelvis to form a fixed mass, or spread to the mucosa at the top of the bladder.
4.Direct implantation of metastatic tumor cells can appear during surgery, and the mass occurs at the bladder incision or under the skin incision after surgery. The recurrence of tumors in the bladder or the appearance of multiple tumors is also partly due to tumor cell implantation. The appearance of tumors in the urethral stump after total cystectomy may also be the result of surgical implantation.
II. Clinical manifestations
Hematuria is the most common and earliest symptom of bladder cancer. Most of them are painless hematuria, and a few of them are microscopic hematuria. The degree of hematuria and anemia is generally proportional to the size of the tumor, but in a few cases a small papillary tumor can bleed repeatedly to the degree of anemia.
The symptoms of bladder irritation, i.e. urinary urgency, frequency and painful urination, are late symptoms and indicate invasive bladder cancer and extensive carcinoma in situ. Tumors adjacent to the bladder neck with the tip can cause difficulty in urination or urinary retention. In children, rhabdomyosarcoma is the most common tumor of the lower urinary tract under the age of 4. Difficulty urinating is the main symptom, along with pyuria and fever, the latter two symptoms often prompting children to seek treatment. Sometimes rhabdomyosarcoma can prolapse from the girl’s urethra and the prolapsed portion may appear necrotic or continue to grow. A pelvic mass can often be palpated on rectal examination.
3.Other symptoms of bladder cancer include swelling of lower limbs, pelvic mass, bone pain, abdominal pain or general symptoms such as wasting and weakness, all of which indicate metastasis of tumor. When the lower abdominal mass is the first symptom, adenocarcinoma of the bladder neck starting from the ureter should be thought of first.
Laboratory and other tests
1.Urine cytology examination has certain significance in the diagnosis of bladder tumor, and the general positive rate is 80%. It can be used as the initial screening of hematuria. In recent years, the application of urine examination of telomerase, bladder tumor antigen (BTA), nuclear matrix protein (NMP22), BLCA-4, etc. can help to improve the detection rate of bladder cancer.
2.Cystoscopy At present, cystoscopy is still the primary means to check bladder tumor, which can initially identify whether the tumor is benign or malignant. Benign papilloma is easy to recognize, it has a clear tip, from the tip many finger-like or villi-like branches floating in the water, the bladder mucosa around the tip tissue is normal. If the tumor has no tip, the base is wide, the surrounding bladder mucosa is not polished, uneven, thickened or edematous and congested, the tumor behaves as a short untidy small protrusion or like a fist block with ulcerated bleeding and grayish pus-like deposits on the surface, the bladder volume is small and the flushed water is cloudy with blood, all of these suggest the presence of malignant tumor. Some tumors are located at the top or anterior wall, which are not easily detected by general cystoscopy and are easily missed by the examiner, the application of flexable cystoscopy can remedy this shortcoming.
With cystoscopy, a biopsy of the tumor can be performed to understand its malignancy and depth. Biopsies can also be taken near and away from the tumor to see if there is epithelial metaplasia or carcinoma in situ, which is an important step in determining treatment options and prognosis. When taking biopsy, we should pay attention to the root of the tumor, because the malignancy of the top tissue is generally higher than that of the root.
3.CT scan can clearly show the bladder tumor of about 1 cm, and can distinguish the depth of infiltration and thickening deformation around the muscle layer and bladder, and can also detect the enlarged lymph nodes in the pelvis. The effect is better after enhancement.
4.MRI has the advantages of easy to clarify the infiltration depth of bladder cancer and whether there is metastasis of lymph nodes, and sometimes it is clearer than CT. It is also easy to distinguish the bladder dome and bottom from the prostate and urethra. It is meaningful for bladder cancer diagnosis and staging.
5.Double diagnosis of bladder can understand the size of tumor, the scope and depth of infiltration and the relationship with pelvic wall. The patient’s abdominal muscle should be relaxed and the examiner should move gently during the examination. To avoid tumor bleeding and metastasis. But nowadays, this examination is rarely used.