Ewing's sarcoma is more common in males (1.6 male:1 female) and usually presents in childhood or early adulthood, with a peak between 10 and 20 years of age. It can occur anywhere in the body, but most commonly in the pelvis and proximal long tubular bones, especially around the growth plates. The diaphyses of the femur are the most common sites, followed by the tibia and the humerus. Thirty percent are overtly metastatic at presentation. Patients usually experience extreme bone pain.

Signs and symptoms include: intermittent fevers, anemia, leukocytosis, increased sedimentation rate, and other symptoms of inflammatory systemic illness. Also, depending on the type, progression, and location of the tumor, great pain may occur.

According to the Bone Cancer Research Trust (BCRT), the most common symptoms are: localized pain, swelling, and sporadic bone pain with variable intensity. The swelling is most likely to be visible if the sarcoma is located on a bone near the surface of the body, but when it occurs in other places deeper in the body, like on the pelvis, it may not be visible.

Ewing sarcoma or Ewing's sarcoma () is a malignant small, round, blue cell tumor. It is a rare disease in which cancer cells are found in the bone or in soft tissue. The most common areas in which it occurs are the pelvis, the femur, the humerus, the ribs and clavicle (collar bone).

Since a common genetic locus is responsible for a large percentage of Ewing sarcoma and primitive neuroectodermal tumors, these are sometimes grouped together in a category known as the Ewing family of tumors.

Ewing sarcoma occurs most frequently in teenagers and young adults, with a male/female ratio of 1.6:1.

Although usually classified as a bone tumor, Ewing's sarcoma can have characteristics of both mesodermal and ectodermal origin, making it difficult to classify.

James Ewing (1866–1943) first described the tumour, establishing that the disease was separate from lymphoma and other types of cancer known at that time.

Many patients first complain of pain that may be worse at night, may be intermittent and of varying intensity and may have been occurring for some time. Teenagers who are active in sports often complain of pain in the lower femur, or immediately below the knee. If the tumor is large, it can present as overt localised swelling. Sometimes a sudden fracture is the first symptom, because affected bone is not as strong as normal bone and may fracture abnormally with minor trauma. In cases of more deep-seated tumors that are not as close to the skin, such as those originating in the pelvis, localised swelling may not be apparent.

A sarcoma is a cancer that arises from transformed cells of mesenchymal origin. Thus, malignant tumors made of cancellous bone, cartilage, fat, muscle, vascular, or hematopoietic tissues are, by definition, considered sarcomas. This is in contrast to a malignant tumor originating from epithelial cells, which are termed carcinoma. Human sarcomas are quite rare. Common malignancies, such as breast, colon, and lung cancer, are almost always carcinoma. The term is from the Greek "sarx" meaning "flesh".

An osteosarcoma (OS) or osteogenic sarcoma (OGS) is a cancerous tumor in a bone. Specifically, it is an aggressive malignant neoplasm that arises from primitive transformed cells of mesenchymal origin (and thus a sarcoma) and that exhibits osteoblastic differentiation and produces malignant osteoid.

Osteosarcoma is the most common histological form of primary bone cancer. It is most prevalent in teenagers and young adults.

Patients usually present with pain and limited range of motion caused by tumor's proximity to the joint space. Swelling may occur, as well, if the tumor has been growing for a long time. Some patients may be asymptomatic until they develop a pathologic fracture at the site of the tumor. They usually originate from the epiphysis of long bones, but in rare cases, they may arise from anterior arc of the ribs.

The symptoms may include muscular aches and pains in arms or legs and abdominal pain. Patients may also experience nerve pain which feels like an electric shock due to weight bearing.

Giant-cell tumor of the bone (GCTOB) is a relatively uncommon tumor of the bone. It is characterized by the presence of multinucleated giant cells (osteoclast-like cells). Malignancy in giant-cell tumor is uncommon and occurs in about 2% of all cases. However, if malignant degeneration does occur, it is likely to metastasize to the lungs. Giant-cell tumors are normally benign, with unpredictable behavior. It is a heterogeneous tumor composed of three different cell populations. The giant-cell tumour stromal cells (GCTSC) constitute the neoplastic cells, which are from an osteoblastic origin and are classified based on expression of osteoblast cell markers such as alkaline phosphatase and osteocalcin. In contrast, the mononuclear histiocytic cells (MNHC) and multinucleated giant cell (MNGC) fractions are secondarily recruited and comprise the non-neoplastic cell population. They are derived from an osteoclast-monocyte lineage determined primarily by expression of "CD68", a marker for monocytic precursor cells. In most patients, the tumors are slow to develop, but may recur locally in as many as 50% of cases.

Dogs with limb osteosarcoma typically show lameness and swelling at the affected site. For other sites, dogs may show difficulty to open their mouth (if jaw bone cancer), nasal discharge (if nasal cavity bone cancer) or neurological signs (if spine bone cancer).

Sarcomas are given a number of different names based on the type of tissue that they most closely resemble. For example, osteosarcoma resembles bone, chondrosarcoma resembles cartilage, liposarcoma resembles fat, and leiomyosarcoma resembles smooth muscle.

Patients with osteoblastoma usually present with pain of several months' duration. In contrast to the pain associated with osteoid osteoma, the pain of osteoblastoma usually is less intense, usually not worse at night, and not relieved readily with salicylates (aspirin and related compounds). If the lesion is superficial, the patient may have localized swelling and tenderness. Spinal lesions can cause painful scoliosis, although this is less common with osteoblastoma than with osteoid osteoma. In addition, lesions may mechanically interfere with the spinal cord or nerve roots, producing neurologic deficits. Pain and general weakness are common complaints.

The most common bone tumor is called osteosarcoma, and typically affects middle-age to older dogs of large and giant breeds. Osteosarcoma is less common in cats. Osteosarcoma is an aggressive cancer that can develop in any bone of the body but the majority is seen in the limbs (e.g. long bones such as radius, humerus, femur, and tibia).

General signs and symptoms include depression, fever, weight loss, loss of appetite, loss of hair or fur and vomiting. Lymphoma is the most common cancerous cause of hypercalcemia (high blood calcium levels) in dogs. It can lead to the above signs and symptoms plus increased water drinking, increased urination, and cardiac arrhythmias. Hypercalcemia in these cases is caused by secretion of parathyroid hormone-related protein.

Multicentric lymphoma presents as painless enlargement of the peripheral lymph nodes. This is seen in areas such as under the jaw, the armpits, the groin, and behind the knees. Enlargement of the liver and spleen causes the abdomen to distend. Mediastinal lymphoma can cause fluid to collect around the lungs, leading to coughing and difficulty breathing. Hypercalcemia is most commonly associated with this type.

Gastrointestinal lymphoma causes vomiting, diarrhea, and melena (digested blood in the stool). Low serum albumin levels and hypercalcemia can also occur.

Lymphoma of the skin is an uncommon occurrence. The epitheliotropic form typically appears as itchy inflammation of the skin progressing to nodules and plaques.

The non-epitheliotropic form can have a wide variety of appearances, from a single lump to large areas of bruised, ulcerated, hairless skin. The epitheliotropic form must be differentiated from similar appearing conditions such as pemphigus vulgaris, bullous pemphigoid, and lupus erythematosus.

Signs for lymphoma in other sites depend on the location. Central nervous system involvement can cause seizures or paralysis. Eye involvement, seen in 20 to 25 percent of cases, can lead to glaucoma, uveitis, bleeding within the eye, retinal detachment, and blindness. Lymphoma in the bone marrow causes anemia, low platelet count, and low white blood cell count.

The cancer is classified into low and high grade types. Classification is also based on location. The four location types are multicentric, mediastinal, gastrointestinal, and extranodal (involving the kidney, central nervous system, skin, heart, or eye). Multicentric lymphoma, the most common type (by greater than 80 percent), is found in the lymph nodes, with or without involvement in the liver, spleen, or bone marrow. Mediastinal lymphoma occurs in the lymph nodes in the thorax and possibly the thymus. Gastrointestinal lymphoma occurs as either a solitary tumor or diffuse invasion of the stomach or intestines, with or without involvement in the surrounding lymph nodes, liver or spleen. Classification is further based on involvement of B-lymphocytes or T-lymphocytes. Approximately 70 percent are B-cell lymphoma. Cutaneous lymphoma can be classified as epitheliotropic (closely conforming to the epidermis) or non-epitheliotropic. The epitheliotropic form is typically of T-cell origin and is also called mycosis fungoides. The non-epitheliotropic form is typically of B-cell origin.

Osteoblastoma is an uncommon osteoid tissue-forming primary neoplasm of the bone.

It has clinical and histologic manifestations similar to those of osteoid osteoma; therefore, some consider the two tumors to be variants of the same disease, with osteoblastoma representing a giant osteoid osteoma. However, an aggressive type of osteoblastoma has been recognized, making the relationship less clear.

Although similar to osteoid osteoma, it is larger (between 2 and 6 cm).

Plasmablastic lymphoma is a type of large B-cell lymphoma, recognized in the WHO 2008 classification. It is CD20 negative, and has an immunophenotype that resembles plasma cells. In formal use, lymphomas with plasmablastic immunophenotype such as primary effusion lymphoma, ALK+ large B-cell lymphoma, large B-cell lymphoma arising in HHV8-associated multicentric Castleman's disease and extracavitary HHV–8-positive lymphoma are not part of this category, although sometimes the literature has confused this point.

The median age of diagnosis is approximately fourth and fifth decades. The disease often arises in the oral cavity, particularly in HIV disease, but other sites include nasal cavity, gastrointestinal tract, skin, bone soft tissue, and lung. There is usually immunodeficiency, such as HIV, organ transplants, autoimmune diseases

Like Burkitt's lymphoma, the morphology has a "starry sky". However, the immunophenotype resembles plasma cells: CD45-, CD20-, CD79a+/-, PAX5-, CD38+, CD38+ and MUM1+. Ki67 is over 90%. EBV is positive in 75%; HHV-8 is negative.

Bone tumors may be classified as "primary tumors", which originate in bone or from bone-derived cells and tissues, and "secondary tumors" which originate in other sites and spread (metastasize) to the skeleton. Carcinomas of the prostate, breasts, lungs, thyroid, and kidneys are the carcinomas that most commonly metastasize to bone. Secondary malignant bone tumors are estimated to be 50 to 100 times as common as primary bone cancers.

A bone tumor (also spelled bone tumour) is a neoplastic growth of tissue in bone. Abnormal growths found in the bone can be either benign (noncancerous) or malignant (cancerous).

Average five-year survival in the United States after being diagnosed with bone and joint cancer is 67%.

Large B-cell lymphoma arising in HHV8-associated multicentric Castleman's disease is a type of large B-cell lymphoma, recognized in the WHO 2008 classification. It is sometimes called the plasmablastic form of multicentric Castleman disease. It has sometimes been confused with plasmablastic lymphoma in the literature, although that is a dissimilar specific entity. It has variable CD20 expression and unmutated immunoglobulin variable region genes.

Infantile myofibromatosis (also known as "Congenital generalized fibromatosis," and "Congenital multicentric fibromatosis") is the most common fibrous tumor of infancy, in which eighty percent of patients have solitary lesions with half of these occurring on the head and neck, and 60% are present at or soon after birth. Less commonly, infantile myofibromatosis presents as multiple lesions of skin, muscle, and bone with about 1/3 of these cases also having lesions in their visceral organs. All of these cases have an excellent prognosis with their tumors sometimes regressing spontaneously except for those cases in which there is visceral involvement where the prognosis is poor. Infantile myofibromatosis and the classic form of mesoblastic nephroma have been suggested to be the same disease because of their very similar histology. However, studies on the distribution of cell-type markers (i.e. cyclin D1 and Beta-catenin) indicate that the two neoplasms likely have different cellular origins.

The signs and symptoms of non-Hodgkin's lymphoma vary depending upon its location within the body. Symptoms include enlarged lymph nodes, fever, night sweats, weight loss, and feeling tired. Other symptoms may include bone pain, chest pain, or itchiness. Some forms are slow growing while others are fast growing. Enlarged lymph nodes may cause lumps to be felt under the skin when they are close to the surface of the body. Lymphomas in the skin may also result in lumps, which are commonly itchy, red or purple. Lymphomas in the brain can cause weakness, seizures, problems with thinking and personality changes.

Castleman disease (CD) is a lymphoproliferative disorder of unknown cause. CD is associated with an increased risk of B-cell lymphoma.

Human herpesvirus 8 (HHV-8), also known as Kaposi sarcoma-associated herpesvirus (KSHV) has been found in some cases of multicentric Castleman disease (MCD). The HHV8 can give rise to an increased number of plasmablast cells within the mantle zone of B-cell follicles. These plasmablasts express IgM-immunoglobulin light chains, most often of lambda subtype. These plasmablasts can give rise to a spectrum of abnormalities including progression to microlymphoma (microscopic clusters of plasmablast cells) or clinical lymphoma.

This type of lymphoma is predominantly seen in acquired immunodeficiencies, including acquired immunodeficiency syndrome (AIDS) but it can also occur in immunosuppression such as with organ transplantation or the elderly. The plasmablasts do not show rearranged immunoglobulin genes, and typically lack EBV infection.

The disease predominantly affects lymph nodes and the spleen, a pattern dissimilar to plasmablastic lymphoma of the oral cavity of AIDS which is not associated with HHV-8 infection. Despite traditional chemotherapy with CHOP (cyclophosphamide, doxorubicin, prednisone, vincristine), and the possible addition of antiviral therapy and inhibition of specific cellular targets including the use of rituximab, the prognosis in this lymphoma has been poor.

This lymphoma subtype has sometimes been confused with plasmablastic lymphoma in the literature, although that is a dissimilar specific entity. Similarly, this subtype is considered distinct from other lymphomas which have a plasmablastic immunophenotype such as primary effusion lymphoma, ALK+ large B-cell lymphoma, and extracavitary HHV–8-positive lymphoma.

HHV8 is also associated with Kaposi's sarcoma and with another subtype of lymphoma, primary effusion lymphoma, previously called body cavity-based lymphoma.

The B-cell lymphomas are types of lymphoma affecting B cells. Lymphomas are "blood cancers" in the lymph nodes. They develop more frequently in older adults and in immunocompromised individuals.

B-cell lymphomas include both Hodgkin's lymphomas and most non-Hodgkin lymphomas. They are typically divided into low and high grade, typically corresponding to indolent (slow-growing) lymphomas and aggressive lymphomas, respectively. As a generalisation, indolent lymphomas respond to treatment and are kept under control (in remission) with long-term survival of many years, but are not cured. Aggressive lymphomas usually require intensive treatments, with some having a good prospect for a permanent cure.

Prognosis and treatment depends on the specific type of lymphoma as well as the stage and grade. Treatment includes radiation and chemotherapy. Early-stage indolent B-cell lymphomas can often be treated with radiation alone, with long-term non-recurrence. Early-stage aggressive disease is treated with chemotherapy and often radiation, with a 70-90% cure rate. Late-stage indolent lymphomas are sometimes left untreated and monitored until they progress. Late-stage aggressive disease is treated with chemotherapy, with cure rates of over 70%.

Castleman disease, also known as giant lymph node hyperplasia, lymphoid hamartoma, or angiofollicular lymph node hyperplasia, is a group of uncommon lymphoproliferative disorders that share common lymph node histological features. The disease is named after Benjamin Castleman.

Castleman's disease has two main forms: It may be localized to a single lymph node (unicentric) or occur systemically (multicentric).

The unicentric form can usually be cured by surgically removing the lymph node, with a 10-year survival of 95%.

Multicentric Castleman disease (MCD) involves hyperactivation of the immune system, excessive release of proinflammatory chemicals (cytokines), proliferation of immune cells (B cells and T cells), and multiple organ system dysfunction. Castleman disease must be distinguished from other disorders that can demonstrate "Castleman-like" lymph node features, including reactive lymph node hyperplasia, autoimmune disorders, and malignancies. Multicentric Castleman's disease is associated with lymphoma and Kaposi's sarcoma.

There are numerous kinds of lymphomas involving B cells. The most commonly used classification system is the WHO classification, a convergence of more than one, older classification systems.