Tumors of the hematopoietic and lymphoid tissues or haematopoietic and lymphoid malignancies are tumors that affect the blood, bone marrow, lymph, and lymphatic system. As those elements are all intimately connected through both the circulatory system and the immune system, a disease affecting one will often affect the others as well, making myeloproliferation and lymphoproliferation (and thus the leukemias and the lymphomas) closely related and often overlapping problems.

While uncommon in solid tumors, chromosomal translocations are a common cause of these diseases. This commonly leads to a different approach in diagnosis and treatment of haematological malignancies.

Haematological malignancies are malignant neoplasms ("cancer"), and they are generally treated by specialists in hematology and/or oncology. In some centers "Haematology/oncology" is a single subspecialty of internal medicine while in others they are considered separate divisions (there are also surgical and radiation oncologists). Not all haematological disorders are malignant ("cancerous"); these other blood conditions may also be managed by a hematologist.

Hematological malignancies may derive from either of the two major blood cell lineages: myeloid and lymphoid cell lines. The myeloid cell line normally produces granulocytes, erythrocytes, thrombocytes, macrophages and mast cells; the lymphoid cell line produces B, T, NK and plasma cells. Lymphomas, lymphocytic leukemias, and myeloma are from the lymphoid line, while acute and chronic myelogenous leukemia, myelodysplastic syndromes and myeloproliferative diseases are myeloid in origin.

A subgroup of them are more severe and are known as haematological malignancies (American spelling hematological malignancies) or blood cancer. They may also be referred to as liquid tumors.

The most common symptoms in children are easy bruising, pale skin, fever, and an enlarged spleen or liver.

Damage to the bone marrow, by way of displacing the normal bone marrow cells with higher numbers of immature white blood cells, results in a lack of blood platelets, which are important in the blood clotting process. This means people with leukemia may easily become bruised, bleed excessively, or develop pinprick bleeds (petechiae).

White blood cells, which are involved in fighting pathogens, may be suppressed or dysfunctional. This could cause the patient's immune system to be unable to fight off a simple infection or to start attacking other body cells. Because leukemia prevents the immune system from working normally, some patients experience frequent infection, ranging from infected tonsils, sores in the mouth, or diarrhea to life-threatening pneumonia or opportunistic infections.

Finally, the red blood cell deficiency leads to anemia, which may cause dyspnea and .

Some patients experience other symptoms, such as feeling sick, having fevers, chills, night sweats, feeling fatigued and other flu-like symptoms. Some patients experience nausea or a feeling of fullness due to an enlarged liver and spleen; this can result in unintentional weight loss. Blasts affected by the disease may come together and become swollen in the liver or in the lymph nodes causing pain and leading to nausea.

If the leukemic cells invade the central nervous system, then neurological symptoms (notably headaches) can occur. Uncommon neurological symptoms like migraines, seizures, or coma can occur as a result of brain stem pressure. All symptoms associated with leukemia can be attributed to other diseases. Consequently, leukemia is always diagnosed through medical tests.

The word "leukemia", which means 'white blood', is derived from the characteristic high white blood cell count that presents in most afflicted patients before treatment. The high number of white blood cells are apparent when a blood sample is viewed under a microscope, with the extra white blood cells frequently being immature or dysfunctional. The excessive number of cells can also interfere with the level of other cells, causing further harmful imbalance in the blood count.

Some leukemia patients do not have high white blood cell counts visible during a regular blood count. This less-common condition is called "aleukemia". The bone marrow still contains cancerous white blood cells which disrupt the normal production of blood cells, but they remain in the marrow instead of entering the bloodstream, where they would be visible in a blood test. For an aleukemic patient, the white blood cell counts in the bloodstream can be normal or low. Aleukemia can occur in any of the four major types of leukemia, and is particularly common in hairy cell leukemia.

For the analysis of a suspected "hematological malignancy", a complete blood count and blood film are essential, as malignant cells can show in characteristic ways on light microscopy. When there is lymphadenopathy, a biopsy from a lymph node is generally undertaken surgically. In general, a bone marrow biopsy is part of the "work up" for the analysis of these diseases. All specimens are examined microscopically to determine the nature of the malignancy. A number of these diseases can now be classified by cytogenetics (AML, CML) or immunophenotyping (lymphoma, myeloma, CLL) of the malignant cells.

Symptoms of cancer in dogs may include:

- Lumps (which are not always malignant, but should always be examined by a vet)

- Swelling

- Persistent sores

- Abnormal discharge from any part of the body

- Bad breath

- Listlessness/lethargy

- Rapid, often unexplained weight loss

- Sudden lameness

- Offensive odor

- Black, tarry stools (a symptom of ulcers, which can be caused by mast cell tumors)

- Decreased or loss of appetite

- Difficulty breathing, urinating or defecating

Lymphoma may present with certain nonspecific symptoms; if the symptoms are persistent, an evaluation to determine their cause, including possible lymphoma, should be undertaken.

- Lymphadenopathy or swelling of lymph nodes, is the primary presentation in lymphoma.

- B symptoms (systemic symptoms) – can be associated with both Hodgkin lymphoma and non-Hodgkin lymphoma. They consist of:

- Fever

- Night sweats

- Weight loss

- Other symptoms:

- Loss of appetite or anorexia

- Fatigue

- Respiratory distress or dyspnea

- Itching

Clinically and pathologically, leukemia is subdivided into a variety of large groups. The first division is between its "acute" and "chronic" forms:

- Acute leukemia is characterized by a rapid increase in the number of immature blood cells. The crowding that results from such cells makes the bone marrow unable to produce healthy blood cells. Immediate treatment is required in acute leukemia because of the rapid progression and accumulation of the malignant cells, which then spill over into the bloodstream and spread to other organs of the body. Acute forms of leukemia are the most common forms of leukemia in children.

- Chronic leukemia is characterized by the excessive buildup of relatively mature, but still abnormal, white blood cells. Typically taking months or years to progress, the cells are produced at a much higher rate than normal, resulting in many abnormal white blood cells. Whereas acute leukemia must be treated immediately, chronic forms are sometimes monitored for some time before treatment to ensure maximum effectiveness of therapy. Chronic leukemia mostly occurs in older people, but can occur in any age group.

Additionally, the diseases are subdivided according to which kind of blood cell is affected. This divides leukemias into lymphoblastic or "lymphocytic leukemias" and myeloid or "myelogenous leukemias":

- In lymphoblastic or lymphocytic leukemias, the cancerous change takes place in a type of marrow cell that normally goes on to form lymphocytes, which are infection-fighting immune system cells. Most lymphocytic leukemias involve a specific subtype of lymphocyte, the B cell.

- In myeloid or myelogenous leukemias, the cancerous change takes place in a type of marrow cell that normally goes on to form red blood cells, some other types of white cells, and platelets.

Combining these two classifications provides a total of four main categories. Within each of these main categories, there are typically several subcategories. Finally, some rarer types are usually considered to be outside of this classification scheme.

Childhood leukemia is a type of leukemia, usually acute lymphocytic leukemia (ALL), and a type of childhood cancer. The cure rate of childhood leukemia is generally higher than adult leukemia, approaching 90%, although some side effects of treatment last into adulthood. The older aggressive treatments of cranial irradiation and anthracyclines (such as doxorubicin) caused increased risk of solid tumors, heart failure, growth retardation, and cognitive defects.

Leukemia is a hematological malignancy or a cancer of the blood. It develops in the bone marrow, the soft inner part of bones where new blood cells are made. When a child has leukemia, the bone marrow produces white blood cells that do not mature correctly. Normal healthy cells only reproduce when there is enough space for them. The body will regulate the production of cells by sending signals of when to stop production. When a child has leukemia, the cells do not respond to the signals telling them when to stop and when to produce cells, regardless of the available space.

Lymphoma is a group of blood cancers that develop from lymphocytes (a type of white blood cell). The name often refers to just the cancerous versions rather than all such tumors. Signs and symptoms may include enlarged lymph nodes, fever, drenching sweats, unintended weight loss, itching, and constantly feeling tired. The enlarged lymph nodes are usually painless. The sweats are most common at night.

There are dozens of subtypes of lymphomas. The two main categories of lymphomas are Hodgkin's lymphomas (HL) and the non-Hodgkin lymphomas (NHL). The World Health Organization (WHO) includes two other categories as types of lymphoma: multiple myeloma and immunoproliferative diseases. About 90% of lymphomas are non-Hodgkin lymphomas. Lymphomas and leukemias are a part of the broader group of tumors of the hematopoietic and lymphoid tissues.

Risk factors for Hodgkin lymphoma include infection with Epstein–Barr virus and a history of the disease in the family. Risk factors for common types of non-Hodgkin lymphomas include autoimmune diseases, HIV/AIDS, infection with human T-lymphotropic virus, immunosuppressant medications, and some pesticides. Eating large amounts of red meat and tobacco smoking may also increase the risk. Diagnosis, if enlarged lymph nodes are present, is usually by lymph node biopsy. Blood, urine, and bone marrow testing may also be useful in the diagnosis. Medical imaging may then be done to determine if and where the cancer has spread. Lymphoma most often spreads to the lungs, liver, and brain.

Treatment may involve one or more of the following: chemotherapy, radiation therapy, targeted therapy, and surgery. In some non-Hodgkin lymphomas, an increased amount of protein produced by the lymphoma cells causes the blood to become so thick that plasmapheresis is performed to remove the protein. Watchful waiting may be appropriate for certain types. The outcome depends on the subtype with some being curable and treatment prolonging survival in most. The five-year survival rate in the United States for all Hodgkin lymphoma subtypes is 85%, while that for non-Hodgkin lymphomas is 69%. Worldwide, lymphomas developed in 566,000 people in 2012 and caused 305,000 deaths. They make up 3–4% of all cancers, making them as a group the seventh-most common form. In children, they are the third-most common cancer. They occur more often in the developed world than the developing world.

Most initial symptoms of leukemia are similar to symptoms for irregular bone-marrow function. Typically, most symptoms do not occur during the early stages of leukemia, and children may experience different symptoms. The following are symptoms of leukemia that lead doctors to look for different types of juvenile leukemia:

Although cats are diagnosed with cancer at lower rates than dogs or humans, the types of cancer and symptoms are identical. Cancer in cats can occur in any location or body system, and most symptoms can be detected externally. However, to reach a definitive diagnosis, further tests such as blood and urine tests, cytology, and biopsy are required. Due to the excessively aggressive nature of cancer in cats, it is advisable for owners to take their cat to a veterinarian for an examination following occurrence of any symptom to prevent spreading.

While each type of cancer has its own distinctive symptoms, most of them can indicate their presence by the occurrence and the prolonged presence of any common symptom. Some of the general symptoms of cancer in cats are:

- Any lump that changes shape or size

- Any sore that does not heal

- Change in bowel or bladder habits

- Difficulty eating or swallowing

- Difficulty urinating or defecating

- Unexplained bleeding or discharge from body

- Loss of appetite

- Chronic weight loss

- Coughing or difficulty breathing

- Stiffness

- Oral odor

Note that ravenous hunger, while a sign of other diseases like hyperthyroid, can also be a sign of cancer.

Cancer is the leading cause of death in dogs. It is estimated that 1 in 3 domestic dogs will develop cancer, which is the same incidence of cancer among men. Dogs can develop a variety of cancers and most are very similar to those found in humans. Dogs can develop carcinomas of epithelial cells and organs, sarcomas of connective tissues and bones, and lymphomas or leukemias of the circulatory system. Selective breeding of dogs has led certain pure-bred breeds to be at high-risk for specific kinds of cancer.

Veterinary oncology is the medical study of cancer in animals, and can be diagnosed and treated by specialized veterinarians called veterinary oncologists.

M2 is a subtype of AML (Acute Myeloid Leukemia).

It is also known as "Acute Myeloblastic Leukemia with Maturation".

Initially, nearby lymph nodes are struck early. The lungs, liver, brain, and bones are the most common metastasis locations from solid tumors.

- In lymph nodes, a common symptom is lymphadenopathy

- Lungs: cough, hemoptysis and dyspnea (shortness of breath)

- Liver: hepatomegaly (enlarged liver), nausea and jaundice

- Bones: bone pain, fracture of affected bones

- Brain: neurological symptoms such as headaches, seizures, and vertigo

Although advanced cancer may cause pain, it is often not the first symptom.

Some patients, however, do not show any symptoms.

When the organ gets a metastatic disease it begins to shrink until its lymph nodes burst, or undergo lysis.

Childhood rhabdomyosarcoma is difficult to diagnose. Factors that increase the likelihood of this cancer include Li-Fraumeni syndrome, type one Neurofibromatosis, Beckwith-Wiedemann syndrome, Costello syndrome, and Noonan syndrome. Each contribute to deformations of bones, tissue, and muscles.

The symptoms of childhood rhabdomyosarcoma are visible and prominent and include swollen red lumps where the cancer starts developing. The lumps are hard and can grow in size unless treated. Other symptoms include poor bowel movements, blood in the urine, secretions from the genitals and nose, and headaches. Various tests can determine whether these related symptoms indicate childhood rhabdomyosarcoma. CT, X-ray, MRI, bone scans, and Ultrasounds may be performed to identify the location and size of the cancer. Biopsies of the lump can be taken along with bone marrow biopsies to detect whether the cancer has spread within the marrow, the bone, and the blood supply. Further determination of how aggressive and large the cancer is requires these scans.

Basal-cell skin cancer (BCC) usually presents as a raised, smooth, pearly bump on the sun-exposed skin of the head, neck or shoulders. Sometimes small blood vessels (called telangiectasia) can be seen within the tumor. Crusting and bleeding in the center of the tumor frequently develops. It is often mistaken for a sore that does not heal. This form of skin cancer is the least deadly and with proper treatment can be completely eliminated, often without scarring.

Local symptoms may occur due to the mass of the tumor or its ulceration. For example, mass effects from lung cancer can block the bronchus resulting in cough or pneumonia; esophageal cancer can cause narrowing of the esophagus, making it difficult or painful to swallow; and colorectal cancer may lead to narrowing or blockages in the bowel, affecting bowel habits. Masses in breasts or testicles may produce observable lumps. Ulceration can cause bleeding that, if it occurs in the lung, will lead to coughing up blood, in the bowels to anemia or rectal bleeding, in the bladder to blood in the urine and in the uterus to vaginal bleeding. Although localized pain may occur in advanced cancer, the initial swelling is usually painless. Some cancers can cause a buildup of fluid within the chest or abdomen.

There are a variety of different skin cancer symptoms. These include changes in the skin that do not heal, ulcering in the skin, discolored skin, and changes in existing moles, such as jagged edges to the mole and enlargement of the mole.

When cancer begins, it produces no symptoms. Signs and symptoms appear as the mass grows or ulcerates. The findings that result depend on the cancer's type and location. Few symptoms are specific. Many frequently occur in individuals who have other conditions. Cancer is a "great imitator". Thus, it is common for people diagnosed with cancer to have been treated for other diseases, which were hypothesized to be causing their symptoms.

People may become anxious or depressed post-diagnosis. The risk of suicide in people with cancer is approximately double.

Bone metastases, or metastatic bone disease, is a class of cancer metastases that results from primary tumor invasion to bone. Bone-originating primary tumors such as osteosarcoma, chondrosarcoma, and Ewing's sarcoma are rare. Unlike hematological malignancies that originate in the blood and form non-solid tumors, bone metastases generally arise from epithelial tumors and form a solid mass inside the bone. Bone metastases cause severe pain, characterized by a dull, constant ache with periodic spikes of incident pain.

The possible signs of oropharyngeal cancer are:

- A sore throat that persists

- Pain or difficulty with swallowing

- Unexplained weight loss

- Voice changes

- Ear pain

- A lump in the back of the throat or mouth

- A lump in the neck

- A dull pain behind the sternum

- Cough

Oropharyngeal cancer is a disease in which cancer form in the tissues of the throat (oropharynx). The oropharynx is the middle part of the throat that includes the base of the tongue, the tonsils, the soft palate, and the walls of the pharynx. Oropharyngeal cancers can be divided into two types, HPV-positive, which are related to human papillomavirus infection, and HPV-negative cancers, which are usually linked to alcohol or tobacco use.

Bone metastases are a major clinical concern that can cause severe pain, bone fractures, spinal cord compression, hypercalcemia, anemia, spinal instability, decreased mobility, and rapid degradation in the quality of life for patients. Patients have described the pain as a dull ache that grows worse over time, with intermittent periods of sharp, jagged pain. Even under controlled pain management, these periods of breakthrough pain can occur rapidly, without warning, several times a day. Pain may be worse at night and partially relieved by activity. Metastases to weightbearing bones may become symptomatic early in the course of disease as compared to metastases to the flat bones of the rib or sternum.

- Effects of bone metastasis

- severe pain

- bone fractures

- spinal cord compression

- hypercalcemia

- anemia

- spinal instability

- decreased mobility

Metastasis is a pathogenic agent's spread from an initial or primary site to a different or secondary site within the host's body; it is typically spoken of as such spread by a cancerous tumor. The newly pathological sites, then, are metastases (mets).

Cancer occurs after cells are genetically altered to proliferate rapidly and indefinitely. This uncontrolled proliferation by mitosis produces a primary heterogeneic tumour. The cells which constitute the tumor eventually undergo metaplasia, followed by anaplasia then dysplasia, resulting in a malignant phenotype. This malignancy allows for invasion into the circulation, followed by invasion to a second site for tumorigenesis.

Some cancer cells known as circulating tumor cells acquire the ability to penetrate the walls of lymphatic or blood vessels, after which they are able to circulate through the bloodstream to other sites and tissues in the body. This process is known (respectively) as "lymphatic" or "hematogenous" spread. After the tumor cells come to rest at another site, they re-penetrate the vessel or walls and continue to multiply, eventually forming another clinically detectable tumor. This new tumor is known as a metastatic (or "secondary") tumor. Metastasis is one of the hallmarks of cancer, distinguishing it from benign tumors. Most cancers can metastasize, although in varying degrees. Basal cell carcinoma for example rarely metastasizes.

When tumor cells metastasize, the new tumor is called a "secondary" or "metastatic" tumor, and its cells are similar to those in the original or primary tumor. This means that if breast cancer metastasizes to the lungs, the secondary tumor is made up of abnormal breast cells, not of abnormal lung cells. The tumor in the lung is then called "metastatic breast cancer", not "lung cancer". Metastasis is a key element in cancer staging systems such as the TNM staging system, where it represents the "M". In overall stage grouping, metastasis places a cancer in Stage IV. The possibilities of curative treatment are greatly reduced, or often entirely removed, when a cancer has metastasized.