Blastoma

Oncologists subdivide cancer not only by the localization of the tumor, but also by the type of cells from which it was formed. And blastoma is defined when the neoplasm is derived from blasts - immature (embryonic) undifferentiated cells. Such tumors can affect various organs, tissues and systems, and most often blastoma is formed in a child.

Epidemiology

Among the types of malignant tumors that arise in early childhood, blastomas are the most common, and it is not uncommon for children to be born with this neoplasm.

Lung blastoma statistically accounts for up to 0.5% of all reported pediatric lung cancer cases.

Blastoma accounts for nearly 16% of all pancreatic neoplasms in five-year-old children.

Neuroblastomas occur in children in 90% of cases, and these tumors are responsible for 15% of deaths in children with cancer.

Causes of the blastomas

In most cases, the causes of blastoma are unknown because it is difficult to find out why, during the formation of the embryo and intrauterine development of the fetus, the progenitor stem cells did not become cells of a certain type to form specific structures and organs, but began to grow uncontrollably, spread and displace normal cells.

Most often blastoma occurs due to genetic mutation or abnormal DNA structure. Also read - Causes of Cancer

By the way, along with malignant blastomas, benign blastomas are also formed. Benign blastoma usually grows slowly, tumor cells are more differentiated and do not spread throughout the body, but the tumor can squeeze nearby tissues and structures. And if a malignant blastoma forms, it can spread from the original site to other parts of the body, displacing healthy cells, i.e. Metastasize.

Risk factors

The researchers say that the risk factors for this type of tumor formation have nothing to do with the environment, the course of pregnancy, or its complications.

But certain congenital syndromes and inherited diseases may increase the likelihood of certain types of blastomas. For example, DICER1-family tumor predisposition syndrome; Beckwith-Wiedemann syndrome; Edwards syndrome (trisomy of chromosome 18); hereditary familial adenomatous polyposis (caused by mutations in one of the tumor suppressor genes): cancer predisposition syndrome (Li-Fraumeni syndrome), and others.

Pathogenesis

Blastomas form when some of the multipotent or unipotent stem cells originating from the inner cell mass of the embryo - embryonic progenitor cells - fail to differentiate into their intended specialized cell type.

But the peculiarity of immature undifferentiated cells is their ability to unlimited proliferation by division (mitosis).

The pathogenesis of this type of tumors is considered to be the result of abnormalities of the normal cell cycle with uncontrolled proliferation of embryonic stem cells mesenchyme (embryonic tissue), which trigger the development of the malignant process. Such abnormalities are caused by mutations in tumor suppressor genes (RB1, APC, ATRX, PTEN, NF1, NF2, etc.) and tumor necrosis factor (TNF) genes; genes encoding RNA synthesis transcription factors; and a number of genes that normally regulate proliferation, differentiation, and the entire cell cycle (including apoptosis).

The development of blastomas of various localizations is also associated with a germline mutation of DICER1 (gene encoding Dicer endoribonuclease), which disrupts the regulation of microRNA synthesis, ribosome biogenesis and gene expression.

The process of transforming normal cells into cancer cells is discussed in more detail in the material - Tumor Cells

Symptoms of the blastomas

Types of blastomas (according to verified diagnoses) are distinguished according to their localization:

• Hepatoblastoma is a blastoma of the liver;
• Nephroblastoma is a blastoma of the kidney;
• Pancreatoblastoma is a blastoma of the pancreas;
• Pleuropulmonary blastoma - blastoma of the lung and/or pleural cavity;
• Retinoblastoma is a blastoma of the eye that arises in its retina;
• Osteoblastoma is a blastoma of the bone;
• Blastoma of the brain - several subtypes depending on location;
• Blastoma of immature nerve cells (neuroblasts) outside the brain - neuroblastoma.

Symptoms of blastoma vary depending on its localization, size and stage. According to the international TNM classification, there are four stages in the case of malignant neoplasm. If there is an isolated tumor in one area without affecting lymph nodes - this is stage I; if the tumor is large and there are signs of unilateral lymph node involvement, stage II is defined; at stage III there are metastases in lymph nodes, and at stage IV tumor metastases affect other organs.

Hepatoblastoma (blastoma of the liver) is considered the most common type of liver cancer in children. It usually appears in children under 3 years of age. The tumor shows symptoms such as: abdominal pain and bloating, nausea and vomiting, lack of appetite and weight loss, itchy skin, yellowing of the skin and whites of the eyes. [1]

See also - Liver tumors in children

A fairly common kidney blastoma among children is nephroblastoma, also called malignant Wilms tumor. The tumor contains metanephric mesenchyme (from which embryonic kidneys are formed), as well as stromal fibrous and epithelial cell elements. The tumor is asymptomatic for long periods of time and manifests itself if it begins to press on the normal kidney parenchyma. Symptoms include abdominal bloating or abdominal pain, fever, urine discoloration and blood in the urine, loss of appetite, nausea and vomiting, constipation, and enlarged veins in the abdominal wall. More information in the article - Symptoms of Wilms tumor [2]

Pancreatoblastoma, i.e. Malignant blastoma of the pancreas, affects children between one and ten years of age (with a peak incidence at the age of five). The tumor is rare, formed from immature cells lining the secretory part of the pancreas; the most frequent localization is the epithelium of its exocrine parts.

Typical symptoms include abdominal pain, vomiting, weight loss, and jaundice. In many cases, the tumor is diagnosed late, when it has an impressive size and metastasizes to regional lymph nodes, liver and lungs. [3]

Blastoma of the lung - pulmonary blastoma or pleuropulmonary blastoma - is a rare, fast-growing tumor that arises in lung tissue or in the outer lining of the lung (pleura) and is composed of atypical epithelial and mesenchymal cells. These tumors occur in infants and young children and rarely in adults. Quite often, the tumor is silent, and symptoms may include coughing, hemoptysis, shortness of breath, fever, chest pain, pleural effusion, and a buildup of blood and air in the pleural cavity (pneumohemothorax). [4], [5]

Blastoma of the eye (retinoblastoma) is a cancerous tumor of the retina in children that occurs during intrauterine development due to a germline mutation of the RB1 gene, which encodes the pRB protein that regulates cell growth and prevents cells from dividing too quickly or uncontrollably.

Signs of retinoblastoma include: redness of the eyes, increased intraocular pressure, change in pupil color (red or white instead of black), pupil dilation, strabismus, different iris color, and decreased vision. [6],

Blastoma of the bone, a benign osteoblastoma, usually affects the spine. And blastoma of the spine most often appears in adolescence. With a superficial lesion, general weakness, local swelling and soreness are observed, and when the tumor presses on the spinal cord or nerve roots, neurological symptoms are observed.

In addition, a rare type of benign tumor, defined as chondroblastoma or Codman's tumor, can occur in the bone growth zone in children and young adults - the area of cartilage near the joints at the ends of long bones (femur, tibia, and humerus). The growth of this tumor can destroy the surrounding bone, causing pain in a nearby joint when moving. There is also swelling of the joint, stiffness, muscle atrophy and, if the lower limb is affected, limping. [7]

Blastoma of the jaw - ameloblastoma of the jaw - is most often diagnosed in adults aged 30-60 years, but can occur in children and young adults. This 98% benign tumor of the maxillofacial region most often localizes on the jaw near the molars; it forms from cells that produce tooth enamel (ameloblasts). A distinction is made between less aggressive and more aggressive types of ameloblastoma, and in the latter case, the tumor is large and grows into the jawbone. Symptoms may include pain, swelling, and lumpiness in the jaw. [8]

Blastoma of the brain

This type of tumor forms from fetal cells in children, and it can be:

• Medulloblastoma (with localization in the posterior cranial fossa - in the area of the midline of the cerebellum); [9]
• Glioblastoma is one of the most aggressive types of cerebral cancer; it usually forms in the white matter of the brain and grows very rapidly. Initial signs include headaches and nausea, with stroke-like symptoms progressing to loss of consciousness. [10]
• pineoblastoma of the brain, arising in the epiphysis of the brain (pineal gland) in children of the first 10-12 years of life, is diagnosed in adults in no more than 0.5% of cases. Patients experience severe headaches and dizziness, convulsions, urges to vomit, numbness of the limbs and peripheral paresis, double vision, memory impairment, and problems with sensory and motor functions. [11]

Read also - Brain Cancer Symptoms

Tumors that form in very early forms of nerve cells (neuroblasts) in infants and young children due to genetic mutations are called neuroblastomas. They can be found anywhere in the sympathetic nervous system because during embryogenesis neuroblasts invaginate, migrate along the nerve axis, and repopulate the sympathetic ganglia, adrenal medulla, and other locations. Most commonly, this mass occurs in one of the adrenal glands, but can also develop in the sympathetic ganglia near the spine in the chest, neck, or pelvis. The first signs of neuroblastoma are often vague (fatigue, loss of appetite, fever, joint pain), and symptoms depend on the location of the primary tumor and the presence of metastases. All details in the publication - Neuroblastoma in children: causes, diagnosis, treatment

Less common types of blastoma include:

• gastric blastoma - gastroblastoma - an extremely rare malignant tumor in people under 30 years of age; in terms of histology, is characterized by the presence of mesenchymal and epithelial components; symptomatology is nonspecific and manifested by anemia, fatigue, abdominal pain, constipation, blood in the stool, vomiting with blood. [12]
• uterine blastoma - angiomyofibroblastoma - is a benign neoplasm up to 5 cm in size, which is a well-defined mass of soft tissue (making it similar to a cyst) and is found in women of reproductive age. Similar neoplasia can occur in the vulvovaginal area. [13], [14]
• Breast blastoma or myofibroblastoma is a rare benign blastoma occurring in menopausal women and older men; it consists of spindle-shaped cells of mesenchymal origin. This type of tumor may be confused with fibroadenoma. [15]
• Ovarian blastoma - teratoblastoma or malignized teratoma of the ovary. [16]
• skin blastoma - cutaneous neuroblastoma. This peripheral neuroblastoma, in the form of a pyogenic granuloma (red papule) or keratinous plaque, is rare in adults. Its histological resemblance to neuroendocrine carcinoma, a round malignant tumor of Merkel cells (tactile epithelial cells of the skin associated with somatosensory afferent nerve fibers), is noted.

Complications and consequences

Complications and consequences of most malignant tumors are metastases in lymph nodes and spread of malignant cells to other organs.

Thus, pulmonary blastoma metastasizes to the brain, lymph nodes and liver; retinoblastoma metastasizes to bone, brain, regional lymph nodes; gastroblastoma - to regional lymph nodes; medulloblastoma - to the soft tissue of the brain and spinal cord.

In addition to metastases, among the complications of neuroblastoma, experts note the compression effect of the tumor on the spinal cord with the development of paralysis, as well as paraneoplastic syndrome. [17]

Diagnostics of the blastomas

Diagnosis of cancer involves a comprehensive examination of patients with fixation of symptoms and collection of anamnesis (including family history).

Blood tests for alpha-fetoprotein (AFP), lactate dehydrogenase (LDH) level, tumor antigens (specific oncomarkers), etc. Are performed. Analysis of cerebrospinal fluid is necessary, as well as biopsy of tumor tissue and its histological examination to clarify the benign or cancerous nature of the neoplasm.

Instrumental diagnosis uses magnetic resonance imaging (MRI), computed tomography (CT) and other imaging techniques.

On the basis of the obtained data, differential diagnosis is carried out.

Read more:

• Cancer screening
• Blood tests for cancer cells

Treatment of the blastomas

What treatment is given when malignant blastoma is diagnosed?

In various combinations, according to treatment protocols are carried out:

• Medication-assisted treatment with medication. Read more:
• Chemotherapy for cancer
• Chemotherapy drugs
• Using X-rays - Radiation therapy for cancer.

Surgical treatment means removing the cancerous tumor.

Prevention

There is no way to prevent blastoma, which is a poorly understood tumor. There are currently no methods to prevent hereditary syndromes that increase the risk of these tumors.

Forecast

In the case of oncology, the prognosis for the outcome of the disease depends on many factors, including its stage at the time of diagnosis, the location of the tumor, the effectiveness of treatment, and others. The prognosis for children with blastoma varies considerably, but, as a rule, it is better the younger the child is.

Because of the rarity of blastomas in adults, little is known about the characteristics of these neoplasms, but research suggests that children have a better chance of survival compared to adults.

The overall survival rate for liver blastoma is estimated at 60% and for retinoblastoma at approximately 94%.

The five-year survival rate for patients with lung blastoma is 16%, for low-risk neuroblastoma it is more than 95%, and for high-risk neuroblastoma it is 40%

If glioblastoma is untreated, it is fatal, on average, in three months.