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Types of blood cancer

The three main types of blood cancer are:

• Leukaemia (involving white cells).

• Myeloma (involving red cells).

• Lymphoma (involving the lymphatic system).

Symptomatology may be related to the abnormal synthesis or function of blood cells or to the accumulation of abnormal cells in various organs or tissues.

Veja também Childhood Leukaemias.

There are several leukaemia types, categorised according to speed of onset (acute or chronic) and stem cell type (eg, myeloid or lymphoid).

Leucemia mieloide aguda (LMA)¹

AML is the most common acute leukaemia in adults. Most subtypes show >30% blast cells of myeloid lineage in the blood, bone marrow, or both.

AML is a genetically heterogeneous disease. Genomic advances have enabled a categorisation based on molecular genetics.

Median onset age is 67.

Identified risk factors include myelodysplastic disorders, some congenital disorders (eg, síndrome de Down, neurofibromatose), and benzene exposure.

Presentation is related to organ infiltration or bone marrow failure. Hepatomegaly, splenomegaly, pallor and petechiae are common findings.

Prognosis depends on the burden of disease, age and cell type.

Veja Acute Myeloid Leukaemia .

Leucemia linfoblástica aguda (LLA)²

ALL occurs when a clone of cells from lymphoid progenitor cells undergoes malignant change. The abnormal cells grow, replacing normal cells in the bone marrow. Immature leukoblasts also pour into the peripheral circulation.

The peak incidence is 2-4 years and ALL represents 80% of childhood cases of leukaemia. Genetic and environmental risk factors have been identified, and an association with viral infections.

The clinical picture is usually one of rapid deterioration, with early nonspecific symptoms of fatigue, malaise, headache and fever. Later, bone marrow failure occurs with haemorrhagic or thrombotic complications, recurrent infections and bone pain.

Veja Acute Lymphoblastic Leukaemia .

Chronic lymphocytic leukaemia (CLL)³

CLL is a malignant proliferation of B lymphocytes. These accumulate in various tissues, including the blood, bone marrow, liver and spleen. They are functionally immature, leading to immune deficiency.

CLL is principally a disease of older people, representing a quarter of all leukaemias. The median diagnosis age is 72 years.

There is an increased incidence in first-degree relatives but the genetic basis is unknown.

The condition is usually associated with a long overall survival.

Veja Chronic Lymphocytic Leukaemia artigo.

Leucemia mieloide crônica (LMC)⁴

CML can affect one or all of the haemopoietic stem cell lines (erythroid, platelet and myeloid). A cytogenic abnormality known as the Philadelphia chromosome is responsible for 90% of cases.

It can occur at any age but is rare in children, It causes 15% of all adult leukaemias and the median diagnosis age is 60-65 years.

Veja Chronic Myeloid Leukaemia .

linfoma de Hodgkin⁵

This is a lymphatic system malignant tumour. The characteristic histological findings are multinucleated giant cells (Reed-Sternberg cells) and smaller mononuclear cells derived from B lymphocytes, in the germinal centres of lymphoid tissue.

Peak incidence is in young adults aged 20-34. Risk factors include infection with Epstein-Barr virus (EBV), HIV, immunosuppression and cigarette smoking.

The most common presentation is with enlarged but painless lymph nodes in the neck or supraclavicular region. Systemic symptoms such as night sweats or weight loss may be present.

Veja Linfoma de Hodgkin .

Non-Hodgkin's lymphoma (NHL)⁶

NHL is a heterogeneous group of myeloproliferative malignancies. They are divided into low-grade or high-grade, depending on their natural history and treatment response.

NHLs have been classified by the World Health Organization (WHO) into subtypes according to clinical presentation and histology.

NHL is five times more common than Hodgkin's lymphoma.

Median presentation age is >50 years; some types occasionally occur in children or young adults.

Risk factors include chromosomal abnormalities, some viral infections, environmental factors, congenital and acquired immune deficiency states, autoimmune disorders and Helicobacter pylori infecção.

Lymphadenopathy and organomegaly are the predominate presenting features.

Veja Linfoma não-Hodgkin .

Mycosis fungoides and cutaneous T-cell lymphomas (CTCLs)⁷

CTCLs are classified by WHO by their clinical behaviour into indolent or aggressive.

Median presentation age is 55-60 years. Mycosis fungoides is the most common type. The typical presentation is with patches and plaques on the skin. Visceral tumours may present later.

Veja nossa Micose Fungoide e Linfomas Cutâneos de Células T .

Linfoma do tecido linfoide associado à mucosa (MALT)⁸

MALT lymphomas are a type of NHL. They are found in mucosa rather than lymph nodes. They are subdivided into gastric (associated with H. pylori) and non-gastric (found in head, lung, neck and eye and not associated with H. pylori).

They are associated with a variety of infections, autoimmune disease and chromosomal abnormalities. They are mostly slow-growing and remain localised for long periods.

Veja Mucosa-associated Lymphoid Tissue (MALT) Lymphoma .

Waldenström's macroglobulinaemia ⁹

This is a lymphoproliferative disorder of B cells, causing infiltration of bone marrow with lymphoplasmacytic cells. Median presentation age is >70 years. Aetiology is unknown but may be related to viral infections, autoimmune conditions or chromosome abnormalities.

Symptomatology is variable and depends on which organ systems are involved.

Median survival is about 60 months.

Linfoma de Burkitt¹⁰

Rapidly growing, this is high-grade B-cell NHL. There are endemic and sporadic forms - both associated with EBV. Chromosome abnormalities have been demonstrated in both types. A third type is linked to HIV infection and use of immunosuppressive drugs.

Children are most commonly affected. The endemic form commonly presents with a tumour of maxilla and/or mandible; abdominal organs may also be involved.

The sporadic type mainly involves abdominal organs. Prognosis may be good if the condition is treated before spreading.

Veja Burkitt's Lymphoma artigo.

Myeloma is a malignant proliferation of plasma cells, caused by genetic mutations. Median presentation age is 70 years. Presenting features may include renal failure, bone pain, anaemia and hypercalcaemia.

Myeloma is chronic, relapsing and remitting. In high-risk disease, death occurs within two years. Advances in treatment have led to some patients surviving beyond 8 years.

Veja Mieloma .

A proliferative myeloid disorder caused by a somatic mutation in a haemopoietic stem cell, this is predominantly associated with erythroid hyperplasia, but also myeloid leukocytosis, thrombocytosis and splenomegaly.

Median diagnosis age is 65-74 years. It may be discovered incidentally on routine blood testing, or with headache, dizziness and sweating symptoms. It can be associated with Síndrome de Budd-Chiari or pruritus. It can progress to myelofibrosis or AML.

Survival without treatment is 6-18 months. With treatment, median survival rate is about 14 years.

Veja Polycythaemia Vera .

Investigation often involves examination of a peripheral blood film, bone marrow biopsy, cytogenetic studies, CXR and CT scans. Other investigations depend on the individual condition and the need to exclude other conditions.

This depends on the individual condition but often involves a period of remission induction, followed by maintenance therapy. Chemotherapy and radiotherapy are frequently the mainstays of treatment.

Stem cell transplant may be indicated in selected cases. Surgery may also be helpful, particularly where organomegaly is a feature.