(1) Benign epithelial tumor

1) papilloma: The tumor grows outward to form a papilla on the surface, which can be cauliflower-like or villous in appearance, and the root covering the epithelium is narrow, forming a pedicle connected with normal tissue. Microscopically, each nipple is composed of branched stroma with blood vessels, and the hyperplastic epithelium covered on its surface can be squamous columnar epithelium or transitional epithelium. Papilloma of external auditory canal, penis, bladder and colon is easy to turn into papillary carcinoma.

2) Adenoma: a benign tumor originating from glandular epithelium. Most adenomas in mucosal glands are polypoid, while adenomas in glandular organs are nodular, often wrapped in capsules, and have clear boundaries with surrounding normal tissues. The structure is very similar to the primary gland, and it often has a certain secretory function, which can secrete serous fluid and mucus. Common in thyroid gland, salivary gland, ovary and breast.

According to their composition or morphological characteristics, adenomas can be divided into cystadenoma, fibroadenoma, pleomorphic adenoma and polypoid adenoma.

① Cystoma is due to the accumulation of glandular secretions in adenoma tissue, and the glandular cavities gradually expand and merge into cystic cavities of different sizes, so it is named mainly in ovary and occasionally in thyroid and pancreas. There are two types of ovarian cystadenoma: one is mucinous cystadenoma, which is often multilocular with smooth cyst wall and few papillary hyperplasia; The other is serous papillary cystadenoma, in which glandular epithelial papillary hyperplasia enters the cyst cavity and secretes serous fluid, so it is called serous papillary cystadenoma.

② Fibroadenoma is the most common benign tumor of female breast, accompanied by hyperplasia of glandular epithelial cells and fibrous connective tissue.

③ Pleomorphic adenoma mainly occurs in salivary gland, especially parotid gland. In the past, it was often called mixed tumor, which grew slowly because of the mixture of mucinous and cartilaginous tissues of glandular tissue, but it often recurred after resection.

④ Polypoid adenoma occurs in mucosa, which is polypoid and pedicled with mucosa, and is more common in rectum. Among them, the malignant rate of papillary or villous surface is high, and polyposis of colon multiple adenocarcinoma is often familial, which not only has a high canceration rate, but also is prone to early canceration.

(2) Malignant epithelial tissue tumor: Malignant epithelial tissue tumor is collectively called cancer, which is more common in people over 40 years old. Mainly invasive growth. Those with unclear boundaries with surrounding tissues are polypoid or cauliflower-like, and the surface is often necrotic and festering. Patients with irregular nodular carcinoma of organs usually metastasize through lymphatic channels in the early stage and hematogenous metastasis in the late stage, which is different from mesenchymal malignant tumors. Malignant mesenchymal tumors mainly pass through blood flow metastasis. The common types of cancer are as follows: 1) Squamous cell carcinoma: it often occurs in the parts covered by the original squamous epithelium, such as skin, mouth, lips, cervix, vagina, esophagus and penis, and it can also occur in squamous metaplasia, such as bronchus, gallbladder and renal pelvis. Although there is no squamous epithelium under normal circumstances, squamous cell carcinoma can occur through squamous metaplasia, and it looks like cauliflower with naked eyes. Microscopically, well-differentiated squamous cell carcinoma with deep infiltration can be observed. Layered keratinocytes are called "cancer beads". The poorly differentiated squamous cell carcinoma has no keratobeads or even intercellular bridges. The tumor cells are obviously atypical and more mitotic images can be seen.

2) Basal cell carcinoma: it is more common in the face of the elderly, such as eyelids, cheeks and nose. Cancer nests are mainly composed of densely stained basal cell-like cancer cells. Basal cell carcinoma grows slowly, often forms ulcers on the surface, which can infiltrate and destroy local deep tissues, but rarely occurs metastatic basal cell carcinoma, which is sensitive to radiotherapy and presents a low-grade malignant course in clinic.

3) Transitional epithelial carcinoma: Transitional epithelium is easy to occur in the bladder and renal pelvis, with multiple nipples, which can fester to form ulcers or widely infiltrate the bladder wall. Microscopically, cancer cells are like transitional epithelium, arranged in multiple layers, with obvious atypia.

4) Adenoepithelial carcinoma: It is a malignant tumor with glandular epithelium, such as gastrointestinal gallbladder and uterine body. Well-differentiated tumors with glandular structure are called adenocarcinoma, poorly differentiated tumors often form solid cancer nests, and those without glandular cavities are called solid cancer.

Mucous carcinoma, also known as glial carcinoma, secretes more mucus and is common in stomach and colonoscopy. It can be seen that mucus accumulates in cancer cells, pushing the nucleus to one side, making the cells look like signet rings, which are called signet ring cells.

5) atypical hyperplasia of precancerous lesions and precancerous lesions of carcinoma in situ: refers to some lesions with potential canceration, which may turn into cancer if they are not treated in time for a long time. Common precancerous lesions include: ① Mucosal leukoplakia: the common mucosa in oral vulva and other places can be transformed into squamous cell carcinoma due to overgrowth, hyperkeratosis and some dysplasia of squamous epithelium.

② Chronic cervicitis with cervical erosion: This is a common gynecological disease. On the basis of chronic cervicitis, the squamous epithelium of cervix and vagina is replaced by a single columnar epithelium from the inner membrane of cervical canal, which can be transformed into cervical squamous cell carcinoma.

③ Adenomatous polyp of rectum and colon: Both single and multiple cases can become cancerous, and multiple cases with family history are more likely to become cancerous.

④ Fibrocystic hyperplasia of breast: It is often caused by endocrine disorders, and intraductal papillary hyperplasia is easy to become cancerous.

⑤ Chronic atrophic gastritis and gastric ulcer: Intestinal metaplasia of gastric mucosa in chronic atrophic gastritis can cause cancer, while chronic gastric ulcer can also cause cancer if it does not heal for a long time, and its canceration rate is about 65438 0%.

⑥ Chronic ulcerative colitis: Colonic adenocarcinoma can occur on the basis of recurrent ulcer and mucosal hyperplasia.

⑦ Chronic skin ulcers: Chronic skin ulcers and fistulas, especially chronic leg ulcers, can cause squamous epithelial hyperplasia and easily become cancerous.

⑧ Cirrhosis: Chronic viral hepatitis progresses to cirrhosis, and a considerable part can further progress to hepatocellular carcinoma.

Atypical hyperplasia: Atypical hyperplasia is the abnormal hyperplasia of epithelial cells, showing a certain degree of atypia, but not enough to be diagnosed as cancer. Squamous epithelium on the surface of skin or mucous membrane can also occur in glandular epithelium, such as severe atypical hyperplasia, which involves more than 2/3 of the whole layer and is difficult to reverse. Precancerous lesions often turn into cancer through this form.

Cancer in situ: Cancer in situ refers to severe atypical hyperplasia of mucous membrane or epidermal squamous epithelium of skin, which almost involves the whole epithelium, but has not penetrated the basement membrane and infiltrated downwards. It is called carcinoma in situ, such as carcinoma in situ of cervix, esophagus and skin.

2. Mesenchymal tumor (1) Benign mesenchymal tumor: This kind of tumor has a high degree of differentiation and maturity, and its tissue structure, cell morphology, hardness and color are similar to the normal tissue from which it originated. Tumors grow slowly, and there are several common types with capsules: 1) Fibroma: collagen fibers in tumor tissue are arranged in bundles and interwoven with each other, and the fibers contain fibroblasts, which are nodular in appearance and similar to surrounding tissues.

2) Lipoma: It mostly occurs in the subcutaneous tissue of the back, shoulders, neck and proximal limbs. It is oblate or lobulated in appearance, enveloped, soft in texture and yellowish in color. The greasy structure with normal adipose tissue is different from normal adipose tissue, because lipoma has irregular lobulated encapsulated tumor tissue and uneven fibrous tissue spacing. Lipoma generally has no obvious symptoms, but it can also cause local pain symptoms, with few malignant changes and easy surgical resection.

3) Hemangioma: it can be divided into hemangioma lymphangioma, in which hemangioma is the most common, mostly congenital, so it can occur in children's hemangioma, but the most common hemangioma of skin can be divided into capillary hemangioma (composed of proliferating capillaries), cavernous hemangioma (composed of dilated blood sinuses) and mixed hemangioma (that is, two kinds of changes coexist). Cavernous hemangioma is a kind of map-like, clear-cut and capsule-free purple-red lesion that can be seen by naked eyes. Infiltration of skin or mucous membrane may be a prominent bright red lump, or it may be a dark red or purplish red lump. Chromogenic lymphangioma is composed of proliferating lymphatic vessels. Lymphatic vessels expand and fuse with each other in a cystic way, containing a lot of lymph, which is called cystic hydroma. This kind of tumor is common in children.

4) Leiomyoma: The common tissues of uterine gastrointestinal tumors are composed of spindle smooth muscle cells with relatively consistent morphology.

Cells are arranged in bundles and intertwined. The nucleus is long and rod-shaped, with blunt and round ends, and mitotic images are rare.

5) Osteoma: It is common in craniofacial bone and mandible, and can also involve limbs. Osteoma is composed of mature bone under osteoscope, but it has lost its normal bone structure and arrangement direction.

6) Chondroma: It can be divided into exochondroma and endochondroma. Microscopically, the tumor is composed of mature hyaline cartilage, with irregular lobulation, light blue or silvery white, translucent, calcification and cystic changes.

(2) Malignant mesenchymal tumors: Malignant mesenchymal tumors are collectively referred to as sarcomas.

The difference between cancer and sarcoma is as follows: 1) The tissue source of cancer is epithelial tissue, and the tissue source of sarcoma is mesenchymal tissue.

2) Incidence rate: cancer is more common, about 9 times that of sarcoma, and it is more common in adults over 40 years old; Sarcoma is rare, mostly occurring in teenagers.

3) General features: the cancer is hard, gray and dry, and the sarcoma is soft, gray-red, moist and fishy.

4) Histological features: Most cancers form cancer nests, the boundary between parenchyma and stroma is clear, and fibrous tissues proliferate; Sarcoma cells are mostly diffuse, the boundary between parenchyma and stroma is unclear, stroma is rich in blood vessels and less in fibrous tissue.

5) Reticular fibers: There are no reticular fibers between cancer cells, but there are reticular fibers between sarcoma cells.

6) immunohistochemistry: cancer cells express epithelial markers (such as cytokeratin), and sarcoma cells express mesenchymal markers (such as vimentin)

7) Metastasis: Most cancers metastasize through lymphatic channels, while most sarcomas metastasize through blood channels.

Common malignant mesenchymal tumor: 1) fibrosarcoma: it is a common type of sarcoma, similar to fibroma, and usually occurs in subcutaneous tissue of limbs.

Well-differentiated fibrosarcoma cells are spindle-shaped with little atypia, while poorly differentiated fibrosarcoma cells have obvious atypia. Well-differentiated fibrosarcoma cells grow slowly, with little metastasis and recurrence, while poorly differentiated fibrosarcoma cells grow faster and are easy to metastasis and recurrence after resection.

2) Malignant fibrous histiocytoma: it mainly occurs in lower limbs, followed by deep soft tissues and retroperitoneum of upper limbs, and is the most common soft tissue sarcoma in the elderly. Fibroblasts and histiocytoma-like cells were mainly seen under electron microscope. In addition, the multinucleated tumor cell atypia of primitive mesenchymal myofibroblastic xanthoma cells is very obvious, and mitosis is moderate or a large number of chronic inflammatory cells can be seen in most tumors. In some areas, fibroblasts can be regarded as spokes. Liposarcoma is considered to have certain diagnostic significance. 3) Liposarcoma: It occurs in deep soft tissue of thigh and retroperitoneum, and comes from primitive mesenchymal tissue. It rarely happens to adults over 40, and it rarely happens to teenagers. Nodular or lobulated can be seen by the naked eye. The surface is usually covered with a pseudocapsule, similar to a normal lipoma. The cross section can be mucinous, or the tumor cells have a uniform fishy smell. The poorly differentiated tumor cells have different shapes.

4) Rhabdomyosarcoma: It is common in children under 65,438+00 years old, and it is common in head and neck urogenital tract and retroperitoneal mirror. It is composed of rhabdomyoblastoma in different stages. According to the differentiation degree, arrangement structure and general characteristics of tumor cells, they can be divided into three types: embryonic rhabdomyosarcoma, acinar rhabdomyosarcoma and polymorphic rhabdomyosarcoma.

5) Leiomyosarcoma: it is more common in uterus and gastrointestinal tract, and the patients are mostly middle-aged and elderly. Microscopically, tumor cells have different degrees of atypical mitosis, which is of great significance to judge the prognosis.

6) Angiosarcoma: Blood vessels originate from vascular endothelial cells and can occur in all organs and soft tissues of the whole body, especially the soft tissues of the head and face, especially the skin. Tumors are prone to necrosis and bleeding. When there are dilated blood vessels, the section can be spongy under the microscope. If the tumor is well differentiated, blood vessels in the tumor tissue are obviously formed, with different sizes and irregular shapes. Endothelial cells in vascular lumen have different degrees of atypia, and poorly differentiated angiosarcoma can be seen in mitosis, and cells often exist.

7) Osteosarcoma: Originated from osteoblasts, it usually occurs in teenagers and long bones of limbs, especially in the lower femur and upper tibia. X-ray can show the characteristic Codman Triangle and the radial image of the sun.

8) Chondrosarcoma: Originated from chondroblasts, usually occurring in pelvis, aged 40-70 years. Microscopically, there are many heteromorphic chondrocytes scattered in the cartilage matrix, and there are many binuclear megakaryocytes and multinucleated giant cells.

(3) Neuroectodermal tumor 1) Retinoblastoma: a malignant tumor originating from the basement of the retina embryo, which usually occurs in infants under 3 years old. This is an autosomal genetic disease with a family history. Most of them happen in one eye, but they may also happen in both eyes. A yellow-white or yellow nodular tumor with obvious bleeding and necrosis can be seen by naked eyes, and the tumor is composed of small round cells under calcification microscope.

2) Pigmented nevus and melanoma: Pigmented nevus is a proliferative lesion of benign hamartoma, which can be divided into borderline nevus and intradermal nevus mixed mole according to its different parts in skin tissue. All three kinds of melanoma are highly malignant tumors that can produce melanin. It is more common in adults over 30 years old, and can be malignant from borderline nevus, or tumor cells can be seen under malignant microscope to be arranged in a nested strip or acinar shape.

(4) Malignant tumor composed of multiple tissues: The essence of tumor is composed of more than two different types of tissues, which are called mixed tumor, common teratoma, renal embryoma and carcinosarcoma.

1) Teratoma: According to the degree of tissue differentiation and maturity, it can be divided into benign teratoma and malignant teratoma. According to the appearance, it can be divided into cystic and solid benign teratoma, also known as dermoid cyst. Cystic malignant teratomas are mostly solid, and they are more likely to metastasize to testis than ovary. Teratomas can metastasize to pelvic cavity and distant organs. It can also be seen in mediastinum, sacrococcygeal retroperitoneal pineal gland and so on.

2) Renal embryoma: Also known as nephroblastoma or nephroblastoma, it develops from immature embryonic tissue left in the kidney, and is more common in children under 5 years old. Tumor components are diverse, except that tumor cells are nested, which is similar to the tubular structure of immature glomerulus, and there are also mucinous rhabdomyosarcoma.

3) Carcinosarcoma: The same tumor contains both cancer and sarcoma.