Neoplasia 瘤形成

Neoplasia • Neoplasia is new, uncontrolled growth of cells that is

not under physiologic control. • A neoplasm can be benign, potentially malignant, or

malignant (cancerous/cancer). • Benign refers to a condition, tumor, or growth that is

not cancerous. This means that it does not spread to other parts of the body. It does not invade nearby tissue.

• Cancer/malignancy/cancerous, is an abnormal growth of cells. A term for diseases in which abnormal cells divide without control and can invade nearby tissues. Malignant cells can also spread to other parts of the body through the blood and lymph systems.

Characteristics of Benign and Malignant Neoplasms(Cancers)

• The difference in characteristics of these neoplasms can be conveniently discussed under the following headings:

• 1. Differentiation & anaplasia 退行性变

• 2. Rate of growth • 3. Local invasion • 4. Metastasis 转移

1. Differentiation and anaplasia

• Differentiation refers to the extent to which parenchymal 实质的 cells resemble comparable normal cells both morphologically and functionally.

• Well-differentiated tumours cells resemble mature normal cells of tissue of origin. Poorly differentiated or undifferentiated tumours have primitive原始的 appearing, unspecialized cells.

• In general, benign neoplasms are well differentiated. Malignant neoplasms in contrast.

2. Rate of growth

• Most benign tumours grow slowly; most malignant tumours grow rapidly.

• In general, the growth rate of neoplasms correlate with their level of differentiation, most malignant neoplasms grow more rapidly than do benign neoplasms.

• On occasions, cancers have been observed to decrease in size and even spontaneously disappear.

3. Local invasion

• Nearly all benign neoplasms grow remains localized to their site of origin and do not have the capacity to invade or metastasize to distant sites, as do malignant neoplasms.

• The growth of malignant neoplasms is accompanied by progressive infiltration渗透, invasion and destruction of the surrounding tissue. Generally, they are poorly demarcated边界清楚from the surrounding normal tissue.

4. Metastasis

• It is defined as a transfer of malignant cells from one site to another not directly connected with it.

• Metastasis is the most reliable sign of malignancy. The invasiveness of cancers permits them to penetrate in to the blood vessel, lymphatic and body cavities providing the opportunity for spread.

Pathways of spread

• 1. Seeding of body cavities and surfaces • 2. Lymphatic spread • 3. Hematogenous(Blood) spread

1. Seeding of body cavities and surfaces (transcoelomic spread)

• This seeding may occur wherever a malignant neoplasm penetrates into a natural “open field”. Most often involved is the peritoneal cavity, but any other cavities such as pleural, pericardial, sub-arachnoid and joint spaces-may be affected.

• Particular examples are tumour arising from gastrointestinal tract, pancreas, breast, and gall bladder may spread to one or both ovaries and the peritoneal cavities.

2. Lymphatic spread

• Lymphatic route is the most common pathway for the initial dissemination of carcinomas.

• The pattern of lymph node involvement follows the natural routes of drainage. Lymph nodes involvement in cancers is in direct proportion to the number of tumour cell reaching the nodes.

• A clinical presence of enlarged lymph node is not necessarily synonymous with a metastasis. Conversely, the absence of cancer cells in reseated lymph nodes does not guarantee that there is no underlying cancer.

3. Hematogenous spread

• Lung & liver cancer are common sites of metastasis Other major sites of hematogenous spread include brain and bones.

• In the circulation, cancer cells form emboli by aggregation and by adhering to circulating leukocytes(WBC) particularly platelets.

Clinical Features of Tumors

Effects of tumour on the host: Both benigin and malignant neoplasms may cause

problems because of 1. location and impingement侵犯on adjcent structures 2. functional activities such as hormone synthesis 3. bleeding and secondary infection when they ulcerate

through adjacent natural surfaces 4. initiation of acute symptoms caused by either

rupture破裂 or infarction梗塞local and hormonal effects

Cachexia 恶病质

• Cachexia is a progressive loss of body fat and lean body mass accompanied by profound weakness, anorexia厌食and anemia. It usually happens on the ending stage of cancer patients.

lung cancer (Carcinomas) • The four major histologic subtypes are

adenocarcinomas (most common), squamous cell carcinoma, small cell carcinoma, and other.

lung cancer • The four major histologic subtypes are : • Adenocarcinomas (a cancer originating in glandular

tissue. )腺癌is most common • Squamous cell carcinoma鳞癌 • Small Cell Lung Carcinoma (SCLC) • Others • Each of these is clinically and genetically distinct.

SCLCs are best treated by chemotherapy, because almost all are metastatic at presentation. The other carcinomas may be curable by surgery if limited to the lung.

lung cancer

ETIOLOGY AND Clinical Course • Smoking is the most important risk factor for lung

cancer; in women and nonsmokers, adenocarcinomas are the most common cancers.

• Carcinomas of the lung are silent in the beginning. In some cases, chronic cough and expectoration call attention to still localized, resectable可切除的 disease. By the time hoarseness, chest pain, pericardial or pleural effusion, or persistent segmental atelectasis肺萎陷or pneumonitis makes its appearance, the prognosis is grim. Too often, the tumor presents with symptoms emanating from metastatic spread to the brain, liver, or bones.

Pancreatic cancer

• The pancreas, located in the abdomen, has endocrine and exocrine functions; cancer cells can develop from both types of functional cells.

• Pancreatic cancer is highly lethal致死的because it grows and spreads rapidly and often is diagnosed in its late stages.

Signs and symptoms • Pancreatic cancer is difficult to diagnose in early stage. • Jaundice • Dark urine: As bilirubin levels in the blood increase, the

urine becomes brown in color. • Light-colored or greasy stools: Bilirubin normally helps

give stools their brown color. If the bile duct is blocked, stools might be pale or gray.

• Itchy skin: When bilirubin builds up in the skin, it can start to itch as well as turning yellow.

• Belly or back pain:Pain in the abdomen (belly) or back is common in pancreatic cancer.

• Nausea and vomiting • Weight loss and poor appetite • Gallbladder or liver enlargement

Pancreatic cancer Treatment

• The only curative treatment is surgical removal of all cancer and a pancreatic transplant; however, most patients are not eligible for a pancreas transplant.

• Chemotherapy after surgery can lower the chances of the cancer returning.

• Chemotherapy for metastatic pancreatic cancer can extend life and improve the quality of life.

Liver Cancer • The liver share the dubious distinction of being

the visceral organs most often involved by metastatic cancers. The most common hepatic neoplasms are metastatic carcinomas, with colon, lung, and breast.

• Primary hepatic malignancies are almost all hepatocellular肝细胞的 carcinomas.

Etiologic associations • Infection with HBV or HCV, alcoholic cirrhosis,

and aflatoxin黄曲霉毒素exposure, and nonalcoholic fatty liver disease 非酒精性脂肪肝病 is increasingly becoming an important risk factor for hepatocellular cancer.

• Many variables, including age, gender, chemicals, viruses, hormones, alcohol, and nutrition, interact in the development of hepatocellular cancer.

Clinical Features • Liver cancer may not cause any signs or symptoms in its early

stages. Signs and symptoms often appear once the tumour grows and causes changes in the body, such as blocking the bile ducts. some signs or symptoms:

• pain in the abdomen, which may move up through the right shoulder

• a lump or mass under the ribs • Nausea / vomiting • loss of appetite /feeling full after a small meal (called early

satiety) • Diarrhea / constipation • weight loss • swelling of the abdomen caused by a buildup of fluid (ascites) • swelling in the legs and feet caused by a buildup of fluid

(edema) • Fatigue/ Weakness