Neoplastic Diseases

Neoplastic Diseases

Neoplasia literally means "new growth". A neoplasm is "an abnormal mass of tissue the growth of which exceeds and is uncoordinated with that of the normal tissues and persists in the same excessive manner after the cessation of the stimuli which evoked the change.

A neoplasm is often referred to as a tumor.

Tumor can be Benign or Malignant.

Benign Tumors: Non cancerous growths, often encapsulated, localized and indolent, resemble the cells of origin, do not metastasize, do not recur after surgery.

Malignant Tumors:   Highly invasive, genetically unstable, cell morphology very different from their tissues of origin, metastasis and recurrence are frequent.


Cancer :  i) UNCONTROLLED PROLIFERATION (AUTONOMY)
                         ii) CAPACITY FOR INVASION AND METASTASIS

Carcinogenesis

The mechanism of how cancers occur is thought to be a multistage, multifactorial process that involves both genetic and environmental factors.

Ø   Initiation. The first step involves the exposure of normal cells to a carcinogen, producing genetic damage to a cell.

Ø   Promotion. The environment becomes altered to allow preferential growth of mutated cells over normal cells. The mutated cells become cancerous.

Progression. Increased proliferation of cancer cells allows for invasion in to local tissue and metastasis.