Neoplasia, Embryonic Tumors of Infancy

Afza.Malik GDA

Characteristics of Malignancy in Neoplasm

Neoplasia,  Embryonic Tumors of Infancy

Neoplasia,  Embryonic Tumors of Infancy, Neuroblastoma, Medulloblastoma, Characteristics Of Malignant Neoplasms, Malignant tumors spread by two ways, Grading and staging of cancer.

Embryonic Tumors of Infancy

    (Tumors In Childhood) Some of these tumors are present at birth, but most develop within the first 5 years of life.

Wilm's tumor (nephroblastoma)

    This renal malignancy manifests as an abdominal man in infancy and early childhood.


    The tumor arises from adrenal medulla or one of the sympathetic ganglia. It appears as abdominal swelling in childhood,


    This highly malignant brain tumor is found in the region of the fourth ventricle near the cerebellum. It occurs predominantly in young children.

    Retinoblastoma This is the highly malignant tumor of the retina found in infancy and early childhood.

Characteristics Of Malignant Neoplasms

Differentiation And Anaplasts

    Lack of differentiation of tumor cells is called) anaplasia. It is a characteristic of cancerous cells and it constitutes one of the features that make a tumor as malignant The anaplastic changes are characterized by

1) Pleomorphism (variation in size and shape) Some cells may be many times larger and other smaller than their neighbors

2) Hyperchromasia :

The nuclei contain an abundance of DNA and are extremely dark staining

3) Disturbed nuclear -cytoplasmic ratio:

Normal ratio is 1:6 but in anaplass size of the nucleus becomes larger and ratio between nucleus and cytoplasm becomes 1:1 Chromatin becomes clumped and is distributed along the nuclear membrane.

4) Mitotic figures:

The numbers of mitotic figures become large reflecting the proliferating activity of the parenchymal cells Higher the number of mitosis , higher is the aggressiveness of a cancer. The mitotic figures are atypical producing tripolar, quadripolar, or multipolar spindles instead of bipolar.

5) Tamar giant cell:

Some giant cell contains only a single huge nucleus while other have two or more nuclei.

6) Loss of orientation:

The normal orientation of one cell to the other is lost, so that they grow in haphazard fashion. Normal orientation of cells to their basement membrane is also lost (loss of polarity).


Mechanisms that make cancer invasive are: Physical pressure.

Reduced adhesiveness of tumor cells.

Increased motility of tumor cells. Loss of contact inhibition

Release of destructive enzymes collagenase and plasminogen activator

All tissues of the body can be invaded by cancer but some are vulnerable and other some resistant or elastic fibers are more resistance than collagen fibers because malignant tumors produce elastase in less quantity than collagenase.

Cartilage is the most resistant of all tissues to invasion.

Arteries are much more resistant to invasion than veins and lymphatics due to higher elastin content in arteries.


Malignant tumors spread by two ways:

    Local spread or Infiltration By this way malignant cells infiltrate the surrounding tissues usually in the line of least resistance, like tissue plans. During infiltration the malignant cells may invade the lymphatics and blood vessels.


    Metastasis is a process in which malignant tumor cells invade vessels or tissue spaces in such a manner that they detach, migrate and are translocated to a distant site, where they lodge and grow in the new location to form a secondary tuner.

The malignant tumors which are locally invasive but never metastasize are (1) Basal cell carcinoma of the skin and (ii) Gliomas of brain.

Essential factors for metastasis
Release of viable tumor cells

    Due to deficiency of calcium, the cell loss adhesiveness and this result in the separation of cells from the main mass. These cells may be carried to some other suitable tissue and there they start growing as a new tumor

Presence of suitable environment:

Spleen and skeletal muscles are rarely. affected by the metastasis.

Lung, liver, bone and adrenals are most suitable for metastasis.

Availability of spreading pathway:

Metastatic pathways

Lymphatic pathway:

    It is the most common pathway for the initial dissemination of carcinomas, but sarcomas may also use this route.

    Blood stream: This pathway is typical for sarcomas, but carcinomas may also use this route. Arteries are less readily penetrated than veins.

    Seeding of body cavities and surfaces: In this pathway malignant neoplasm penetrates into natural open field eg peritoneal cavity, pleural, pericardial and joint spaces. Such seeding is characteristics of ovarian carcinoma in which all pericardial and joint spaces. Such seeding is characteristics of ovary carcinoma in which all peritoneal surfaces become coated with heavy layer of cancerous cells.

Transplantation: This is a process of mechanical transport of tumor fragments by instruments or gloved hands.

Grading and staging of cancer

Grading It is a method by which the level of differentiation of cancer is determined. The cancers are died in grade- to grade IV with increasing

Staging a method by which the extent of spread of a cancer is determined. It is based on.

Size of primary lesion

Is extent of spread to regional nodes

Presence or absence of metastasis.


TNM system is used for staging the cancer. It is characterized by:

T- for primary tumor

N for regional lymph node M for metastasis

T1, T2, T3 and T4 describe increasing size of the primary tumor.

N.NI N2. and NJ indicate progressively advancing lymph node involvement MO and MI reflect absence or presence of metastasis

Note: Grading is done on pathological ground while staging is done on clinical ground

Changes In Cell Due to Malignancy

The changes in a cell when it becomes malignant are the following

Changes in growth property

    The cell escapes from regulatory control, fails to become mature and acquires the capacity of transplantation (can grow in artificial media).

Morphological changes Variation in size and shape occurs

Karyotypical changes :Changes occur in genes eg change in the

Philadelphia chromosome in chronic myelogenous leucxkemia

Antigenic changes

    The tumor cells best antigens that are different from those of normal cells, which are recognized by the host immune system that produces immune response to destroy the tumor. The tum antigens may be of three types

    Tumor specific antigens: They are only present on tumor cells and not on any normal cells eg melanoma associated antigen-1 6

    Tumor associated antigen: They are present on tumor cells and also on some normal cells eg prostate-specific antigen

    Oncofetal antigens: This group of antigen consists of substances normally produced in quantity during fetal life hat not to any great extent by adult cells Le, they are produced by tumors eg carcinoembryonic antigen and alpha fetoprotein

Metabolic changes:

    The more anaplastic and undifferentiated the tumor cell, the greater the deviation from the enzyme system of the normal cells.

Cell membrane changes

There is loss of adhesiveness to other cells. Synthesis and release of growth factor

Impaired cell-to-cell communication.

Elaboration and release of degradative enzymes

Tumor cell products

    The synthesis and secretion of various tumor cell products are important for two reasons. Their presence may indicate the existence of a neoplasm in the body ie . they act as tumor markers.

They may produce clinical effects called paraneoplastic syndromes:

Tumor Markers
Oncofetal antigen

    These are antigens that are normally expressed only in fetal life, but may be produced by neoplastic cells, eg

    Carcinoembryonic antigen (normally present in embryonic and fetal endodermal tissue) is found in most malignant neoplasms arising from tissues that develop from embryonic endoderm such as colon and pancreatic cancers

    Alpha Fetoprotein They are synthesized by normal yolk sac and fetal liver-and then by carcinoma of liver and yolk sac carcinoma of gonads.

  • Example is increased serum acid phosphatase in carcinoma of prostate.
  • Raised in multiple myeloma.
  • Excessive hormone production
  • In neoplasm of endocrine cells. Ectopic hormone production.

Post a Comment


Give your opinion if have any.

Post a Comment (0)

#buttons=(Ok, Go it!) #days=(20)

Our website uses cookies to enhance your experience. Check Now
Ok, Go it!