How many types of malignant tumors are there?

Types of malignant tumors:

Almost any part of the human body, any tissue, can develop tumors.

According to the origin of the malignant tumor, those that grow from epithelial tissues such as skin, mucous membranes, and glands are called cancers.

Such as gastric cancer, liver cancer, lung cancer, esophageal cancer, cervical cancer, breast cancer, colon cancer, rectal cancer, nasopharyngeal cancer, ovarian cancer, renal cancer, bladder cancer, thyroid cancer, and skin cancer.

Sarcomas are malignant tumors that arise from mesenchymal tissues such as muscle, fat, bone, blood vessels, and lymph. Examples include rhabdomyosarcoma, leiomyosarcoma, fibrosarcoma, liposarcoma, osteosarcoma, chondrosarcoma, angiosarcoma, lymphosarcoma, and kaposi sarcoma.

Specially named malignant tumors

There are also some malignant tumors which have alternative names due to historical reasons, such as leukemia, Hodgkin’s lymphoma, Wilms’ tumor, melanoma, retinoblastoma, testicular seminoma, granulosa cell tumor, Krukenberg tumor, Ewing’s tumor, malignant vascular endothelial tumor, and Paget’s disease of the breast.

Since cancer is far more common than sarcoma (and other malignant tumors), approximately 9:1, meaning that out of 10 patients with malignant tumors, 9 have cancer and 1 has sarcoma. Therefore, malignant tumors are generally referred to as cancer.

There are 62 types of human cancer according to the International Classification of Diseases, with the highest incidence rates being digestive system cancers and respiratory cancers, such as gastric cancer, liver cancer, lung cancer, esophageal cancer, colorectal cancer, etc.

Types of malignant tumors on several criteria

Malignant tumors are classified based on several criteria, including the type of tissue from which they originate, their histological grade, and their stage of progression. Here’s a detailed breakdown:

1. Origin of Tissue: Malignant tumors are named according to the type of tissue from which they arise. For example, a tumor that originates from epithelial cells is called an “adenocarcinoma” if it arises in glandular tissue, or a “squamous cell carcinoma” if it arises in squamous epithelial tissue. If it originates from connective or supportive tissue, it might be called a “sarcoma.”
2. Histological Grade: This refers to how closely the tumor cells resemble normal cells and how quickly they are likely to grow and spread. Tumors are graded from low to high grade. Low-grade tumors tend to grow slowly and resemble normal tissue, while high-grade tumors grow more quickly and are less differentiated, meaning they look less like normal tissue.
3. Stage of Progression: The stage of a tumor describes its size and how far it has spread from where it started. Staging is typically based on the TNM system, which stands for Tumor size, Node involvement, and Metastasis. Tumor size (T) indicates how large the primary tumor is. Node involvement (N) indicates whether the cancer has spread to the lymph nodes. Metastasis (M) indicates whether the cancer has spread (metastasized) to other parts of the body.
4. Other Factors: Additional factors that may influence classification include the molecular characteristics of the tumor, such as the presence of specific genetic mutations or protein expression patterns, which can help in determining treatment options and predicting prognosis.

These classifications help doctors determine the best course of treatment and provide important information about the tumor’s behavior and potential outcomes.

Malignant tumors based on the origin of tissue

The classification of malignant tumors based on the origin of tissue is a fundamental aspect of cancer diagnosis and treatment planning. This classification system helps in understanding the nature of the tumor, its behavior, and the potential treatment options. Here’s how it works:

1. Epithelial Tissues: These are the tissues that line the surfaces and cavities of the body, including the skin, and the linings of organs and glands. Cancers arising from epithelial tissues are called carcinomas. There are several types:
   • Adenocarcinomas: These arise from glandular epithelial cells and are commonly found in the breast, prostate, lung, and colon.
   • Squamous Cell Carcinomas: These arise from flat, squamous epithelial cells and are often found in the skin, lungs, and areas of the digestive and urinary tracts.
   • Basal Cell Carcinomas: Primarily found in the skin, these are the most common type of skin cancer.
   • Carcinomas In Situ: These are early-stage cancers that are still confined to the layer of tissue in which they developed.
2. Connective and Supportive Tissues: These include bone, cartilage, fat, muscle, blood vessels, and other fibrous tissues. Cancers arising from these tissues are called sarcomas. Examples include:
   • Osteosarcomas: These arise from bone cells and are common in children and young adults.
   • Liposarcomas: These arise from fat cells and can occur anywhere in the body where fat is present.
   • Rhabdomyosarcomas: These arise from muscle cells and are more common in children.
3. Blood and Lymphatic Tissues: Cancers arising from these tissues are generally referred to as leukemias or lymphomas. Examples include:
   • Leukemias: These are cancers of the blood-forming tissues, including bone marrow, and involve the uncontrolled production of blood cells.
   • Lymphomas: These are cancers of the lymphatic system, including the lymph nodes, spleen, thymus, and bone marrow.
4. Neuroectodermal Tissues: These include the tissues of the nervous system and certain glands. Cancers arising from these tissues are called neuroectodermal tumors or neuroendocrine tumors. Examples include:
   • Gliomas: These are tumors of the brain and spinal cord.
   • Neuroblastomas: These are tumors that arise from immature nerve cells and are most common in children.
   • Pancreatic Neuroendocrine Tumors (NETs): These arise from cells in the pancreas that produce hormones.
5. Germ Cells: These are the cells that give rise to sperm in males and eggs in females. Cancers arising from germ cells are called germ cell tumors and can occur in the testes or ovaries.

This classification system is crucial for determining the appropriate treatment approach, as different types of tumors may respond differently to various therapies.