Glossary

B lymphocytes
subtype of lymphocytes; they develop in the bone marrow and are responsible for the recognition of pathogens and the formation of antibodies.

B-symptoms
certain non-specific symptoms that often occur simultaneously in cancer patients: recurrent fever (above 38°C) for no apparent reason, night sweats and unintentional weight loss (more than 10% of body weight in six months). The three symptoms are grouped together under the term B symptomatology. In this combination, they occur primarily in patients with Hodgkin lymphoma and Non-Hodgkin lymphoma and are associated with an unfavourable prognosis.

bacteria
tiny organisms consisting of a single cell without a nucleus that can cause numerous diseases (bacterial infections), but these can be treated successfully with antibiotics for the most part;
Example / Relevance Pediatrics: in the context of cancer treatment, there is an increased risk of bacterial infections for affected patients due to the immunosuppressive effect of the cytostatic drugs.

Beckwith-Wiedemann syndrome (Abrev.: BWS)
congenital or acquired clinical condition, characterized in particular by a pathologically increased one-sided growth of the body (hemihypertrophy), enlargement of the liver, spleen or kidneys, considerably enlarged tongue, umbilical (cord) rupture, maldevelopment of the auricles, kidney abnormalities and an increased risk to develop certain malignant diseases (especially Wilms tumours); BWS is one of the cancer predisposition syndromes and is caused by various genetic changes (on chromosome 11).
Example / Relevance Pediatrics: children and adolescents with BWS have an increased risk of developing a Wilms tumour, a liver tumour (hepatoblastoma), a soft tissue sarcoma (rhabdomyosarcoma) or a neuroblastoma.

beta-thalassaemia syn. ß-thalassaemia
congenital, chronic disease caused by a change in the red blood pigment (haemoglobin); beta-thalassaemia is one of the haemoglobinopathies and is the most common form of thalassaemia. It occurs mainly in the Mediterranean region and is not curable.
References: haemoglobin

biopsy
removal of a tissue sample for subsequent (mainly microscopic) examination; this can be done, for example, by puncture with a hollow needle, with the use of special instruments (such as forceps, punching instruments, probes) or surgically with a scalpel.

bisphosphonates (Abrev.: BP)
substances that inhibit bone resorption, thereby maintaining bone structure and strength; they are often used to treat benign bone diseases, such as osteoporosis.

blastema
undifferentiated germ tissue consisting of stem cells that are capable of dividing, from which differentiated tissue forms during embryonic development or regeneration processes; for example, an early embryonic organ (blastema) develops into a mature, functioning organ via cell proliferation and maturation (differentiation).
Example / Relevance Pediatrics: Wilms tumors arise from degenerated germ tissue, which usually consists of progenitor renal cells.

blasts
immature (here also degenerated) progenitor cells of white blood cells (leukocytes) or their subtypes (e.g. granulocytes, lymphocytes)

blood coagulation
phased solidification of the liquid blood; intact blood clotting is important, for example, in haemostasis and wound healing during or after surgery. Impaired blood clotting leads to an increased tendency to bleed and/or prolonged bleeding time (e.g. after an injury). Increased blood clotting can cause thrombosis, for example.

blood count
blood test to determine the qualitative and quantitative composition of the blood in a blood sample: the number of red and white blood cells as well as platelets, the haemoglobin content (Hb value) of the blood and the volume fraction of red blood cells in the entire blood volume (haematocrit) are assessed. The "complete blood count" also includes a so-called differential blood cell count, in which the white blood cells in particular are examined more precisely for their composition (percentages of the various subtypes) and their appearance.

blood group
hereditary, usually stable, structural characteristics (blood group antigens) of blood components (e.g. AB0 blood groups) located on the cell walls of blood and other tissue cells;
Example / Relevance Pediatrics: before each transfusion of blood products, e.g. in patients with leukaemia or anaemia, it is necessary to check whether the donors blood group matches that of the recipient so that there is no rejection or intolerance reaction. In the case of blood intolerance, one persons red blood cells clump together when mixed with anothers blood serum (antigen-antibody reaction).

blood plasma
component (about 60%) of the blood; yellowish-white fluid consisting mainly of water (about 90%), proteins, electrolytes, and vitamins
References: protein - vitamins

blood stem cells
precursor cells of all blood cells, which give rise to red blood cells (erythrocytes), white blood cells (leukocytes), platelets (thrombocytes) and some other cells. This process is called blood formation. The various blood cells are formed in the bone marrow before they enter the blood stream.

blood transfusion
transfer of blood (whole blood) or blood components (e.g. red blood cells or platelets) from a donor to a recipient.
Example / Relevance Pediatrics: blood transfusions are necessary for many patients with severe anaemia as a result of a congenital blood disease or as part of cancer treatment. Before a transfusion, it is always ensured that the recipient and donor have the same blood group (exception: in the case of universal donor blood group 0).

blood-brain barrier
barrier between the blood and the central nervous system (CNS) that is permeable only to certain endogenous and foreign substances, thereby enabling active control over the exchange of substances with the CNS;
Example / Relevance Pediatrics: some cytostatic drugs cannot cross the blood-brain barrier due to their chemical properties; for the treatment of brain tumours or brain metastases of other cancers, they are therefore not administered intravenously, but directly into the cerebrospinal fluid (intrathecal) (e.g. methotrexate; Ara-C)

Bloom syndrome
rare hereditary disorder characterized by growth disorders, pigmentation defects, photosensitivity, fertility disorders, increased susceptibility to infections and increased risk of cancer (leukaemias and solid tumors); the affected patients develop several tumours in the first two years of life, which are rare in the rest of the population. Bloom syndrome is therefore one of the cancer predisposition syndromes.

bone marrow
site of blood formation; spongy tissue with a strong blood supply that fills the cavities inside many bones (e.g., vertebrae, pelvic and thigh bones, ribs, sternum, shoulder blade, and collarbone); in the bone marrow, all forms of blood cells develop from blood progenitor cells (blood stem cells).

bone marrow punch biopsy
removal of bone marrow tissue for the purpose of examining the cells; with the help of a special hollow needle, a tissue cylinder about 2 cm long is punched out of the bone. The examination is always carried out under anesthesia. A bone marrow punch biopsy may be necessary in addition to or instead of a bone marrow puncture if the latter does not provide sufficient tissue for a reliable examination. Like the bone marrow puncture, it is usually performed from the posterior iliac crest bone. There, the bone marrow is only separated from the skin by a relatively thin layer of bone, so that the removal can take place without significant risk.
Example / Relevance Pediatrics: Bone marrow samples such as punch biopsy play a role in paediatric cancer medicine, especially in the diagnosis of leukaemia and lymphoma, as well as in all malignant diseases that can metastasize to the bone marrow.

bone marrow puncture
removal of bone marrow tissue to examine the cells; during the puncture, a few milliliters of liquid bone marrow are drawn from the pelvic bone or sternum into a syringe with the help of a thin hollow needle. The puncture is performed under local anaesthesia in older children; a sedative may also be administered (sedation). For smaller children, a short period of anesthesia may be appropriate.

brachytherapy syn. short-distance irradiation, interstitial irradiation
treatment of tumours with ionising radiation at short distances; usually a radiation carrier (iodine or ruthenium applicator) is surgically inserted into the tumour tissue to remain there until the desired radiation dose is reached. Since the radiation is only emitted in the direction of the tumour, adjacent, healthy tissue can be protected from radiation.
Example / Relevance Pediatrics: local treatment method, e.g. for small retinoblastoma or brain tumours

brain
the part of the central nervous system (CNS) located in the head; the brain is protected by the skull and the meninges and consists mainly of nerve tissue.

brainstem
the section of the brain that forms the transition between the brain and the spinal cord; it controls vital functions, such as breathing, heart rate and blood pressure, and is responsible for important reflexes such as the blinking, swallowing or coughing reflex, lacrimation and saliva production. This is also where the roots of the cranial nerves are located.
Example / Relevance Pediatrics: About 10–20 % of CNS tumours in childhood and adolescence are brainstem tumours. Most of them are gliomas.