Patho exam 1 Neoplasia

Neoplasia-”new growth” and an overgrowth of a tissue

Neoplasm-neoplastic mass

•        Aka-tumor (abnormal swelling)

•        Term is now synonymous with neoplasia

•        Oncology-study of tumors(oncos=tumor)

•        Neoplasms proliferate to form new tissue (irreversible)

•        They do not wait for signals from the body that the new tissue is needed

•        They ignore signals to stop dividing: Become autonomous

•        They often do not mature normally to do the “job” the tissue is supposed to do

•        They do not die off (apoptosis) to keep the number of total cells constant

NOMENCLATURE

Typically put into one of two categories: Benign or Malignant

•        Benign-suffix ‘oma’ is used with the tissue type

Benign tumors are generally named according to the tissues from which they arise

¤ Glandular – adenoma

¤ Fatty – lipoma

¤ Muscle – myoma

¤ Vascular – angioma

¤ Brain – Meningioma

Some grey area to this rule with epithelial tumors

¤ Some names are based on structure, for example

¤ Papilloma= warty type appearance

¤ Malignant tumors are classified according to the embryonic origin of tissue.

Cancer: malignant neoplasm

¤ Malignancy = potential to spread quickly and throughout the body resulting in death

¤ CARCINOMAS

¤  Malignant tumors of the skin and epithelial lining of the gi and respiratory tract and glandular tissue  (derived from endoderm and ectoderm)

¤ further designated by the type of epithelial tissue

¤ squamous cell carcinoma-skin surface

¤ basal cell carcinoma-deep layer of skin becomes neoplastic

¤ adeno(gland)carcinoma of pancreas

¤ transitional cell carcinoma of bladder

¤ SARCOMAS

¤ Malignant tumors that ARISE FROM CONNECTIVE TISSUE and SUPPORTING TISSUE

¤ References a particular tissue of origin

¤  Ex: chondrosarcoma, osteosarcoma, fibrosarcoma

¤ LEUKEMIA

¤ Neoplasms arising from blood forming tissues

¤ Precursors of White blood cells in bone marrow proliferate and crowd out normal blood forming cells.

¤ Enter into the blood stream circulate in peripheral blood.

EXCEPTIONS: Some terms do not follow the rules and are malignant even with the “oma” ending

¤ Lymphoma – Malignancy of Lymphoid tissue

¤ Should be called: Lymphosarcoma

¤ Melanoma – Malignancy of melanocytes

¤ Should be called a Malignant melanoma

¤ Glioma can be benign or malignant

¤ Pediatric Neoplasms ending in "-blastoma" resemble primitive embryonic tissues. Examples include:

¤ Retinoblastoma

¤ Neuroblastoma

¤ Hepatoblastoma

¤ Medulloblastoma

CHARACTERISTICS OF TUMORS

BENIGN

•        Contain cells that look like normal tissue cells

•        Slow growing: mitotic cells are very rarely present during microscopic analysis

•        May perform the normal function of the tissue (like secreting hormones)

•        This may lead to over secretion

•        Anatomy

•        surrounding capsule of connective tissue.

•         They retain recognizable tissue structure and do not invade beyond their capsule

·                        Generally, are localized, and remain in the tissue in which they  

                                          originated

•         they do not spread to regional lymph nodes or distant locations.

•        Though benign, they may cause problems through mass effect, particularly in tight quarters (pituitary adenoma in the sella turcica).

•        they can damage nearby organs by compressing them

MALIGNANT NEOPLASMS

ANATOMY and GENERAL CHARACTERISTICS

•                                                               Contain cells that do not look like normal adult cells and lose cellular differentiation—"Anaplasia”

•        Differentiation refers to the extent that the parenchymal cell resembles normal cells

•                                                               Malignant cells are also pleomorphic (marked variability of size and shape of cell and nuclei)

•        Mitotic figures are seen (especially irregular or bizarre mitoses).

•         cells divide rapidly----tumors grow quickly

•        The tumor does not have clear boundaries and sends “legs” and invade surrounding tissue

•        Do not perform the normal functions of the organ

·       May secrete hormones associated with other tissues

•        Can compress and/or destroy the surrounding tissues

•        Cells secrete enzymes and can penetrate surround tissue and vessels

•        Promote blood vessels growth to the tumor

METASTASIS

•        Cells in a primary tumor develop the ability to escape and travel in the blood or lymph

•        Secondary site has same tumor cells as primary site

•        The secondary tissue is normal but, has tumors cells from the first site

•        These secondary deposits are called metastatic tumors

PATTERNS OF SPREAD OF MALIGNANT TUMORS

DIRECT EXTENSION : (invasion) into surrounding tissues.

WITHIN BODY CAVITIES (seeding)—by penetrating the wall of an organ, move into a body cavity and spread throughout the area

LYMPHATIC SPREAD

•        Lymphatic vessels similar to veins, easy to invade

•        Lymph nodes are easily invaded and become secondary sites

·       Sentinel node describes the initial lymphnode that is invaded

•        Tumor can then enter into blood

HEMATOGENOUS SPREAD

•        Usually starts at thin wall capillaries/veins

•        Eventually leads to r atrium

•        Then to lungs, lodges in small vessels and the cells become actively invasive, secreting enzymes that promote passage into lung tissue. Therefore, lung common site for metastasis

• Liver is also common b/c of hepatoportal circulation-this is venous drainage of gastrointestinal tract. Colon cancer, for example.

ETIOLOGY

·       There is no single mechanism by which a neoplasm arises.

·        Many different mechanisms give rise to neoplasms, and that is what makes    

diagnosis and treatment so challenging.

·       All cancers involve the malfunction of genes that control cell growth and division

Genetic alteration is the basis for the development of cancer

GENETIC INVOLVEMENT

•        The autonomous growth of neoplastic tissue is based on defects in the genes that regulate the fine balance of cell production versus cell loss by apoptosis.

•        DNA damage involving certain genes (proto-oncogenes & tumor suppressor genes, for example)

•        PROTO –ONCOGENES-Regulates normal growth function in cells

•        Can mutate and can convert into an oncogene

•        Oncogene-stimulates excessive cell growth

•         ‘gene that causes cancer’

       CARCINOGENESIS

•        Initiation: Initial mutation occurs

•        Promotion: Mutated cells are stimulated to divide

•        Progression: Tumor cells compete with one another and develop more mutations which make them more aggressive

          CARCINOGENS

•        These factors may act together or in sequence to cause cancer.

•        Ten or more years often pass between exposure to external factors and detectable cancer.

•        EXAMPLES

•        Ultraviolet, x-radiation, gamma radiation

                           depends on dose, duration, and the body          part of exposure

                           can take years to manifest damages

                     UV rays lead to DNA mutations

Can give rise to squamous cell carcinomas and malignant   

melanomas

•        Chemical carcinogens: Directly damage DNA àmutations àcancer

•        Tobacco in cigarettes (lung cancer)

•        Viral cause-viruses can transform cells

                                  Interact with chromosomal DNA

•        Human papillomavirus  and Herpes  virus type 2 are linked to cervical cancers

•                                                                                Genetic factors

                           women from population groups with a higher frequency of mutations                                     in the breast cancer susceptibility genes (BRCA1 and BRCA2)

CLINICAL MANIFESTATIONS

variable depending on type and site of neoplasia

•        local-damage is confined to one area of the body

•        systemic-lesions are distributed throughout the body

•                         Evidence of Mass

•     Pain

•        Local destruction of tissue, invasion of nerve, by obstructing hollow organs, causing inflammation and pain

•        Obstruction

From within lumen of organ or vessel or external compression

• Hemorrhage

Ulceration secondary to destruction and blood vessel involvement

•        Occult blood in feces or CBC (anemia) can detect bleeding

•        Hematuria with genitourinary tumors

•        Pathologic fractures

•        Primary bone tumor

•        Common site for metastasis in lung, breast, and prostate cancer

•        Weakening and destruction of bone and results in fractures with minimal trauma

•     Infection

Common complication of neoplasia

Most common cause of death

•        Cachexia

Generalized muscle wasting

•        Anorexia, increased nutritional demands, inflammatory response results in anorexia

•        Cancer cachexia syndrome: Weight loss, Muscle wasting, Weakness, Anorexia, & Anemia

DIAGNOSTIC TEST

•        Definitive diagnosis is by tissue biopsy or from blood smears or cytology—you must look at the cells!

Screening tests are recommended for most common types of cancers

PAP smear

mammography

                         Colonoscopy-can be curative!

•        Tumor marker tests. Tumor markers are chemicals made by tumor cells that can be detected in the   blood.  (limitations)

PROGNOSIS

•        The smaller and more localized the tumor the better the prognosis

•        Staging and grading of tumors are systems used to prognosticate and design therapy protocols

•        Stage describes the extent of spread in the body

•        TNM system and Stages I-IV

•        Grade considers the appearance of cells microscopically-I - IV

TREATMENT

•        Surgery

•        Radiation Therapy

•        Chemotherapy, Hormone and Antihormone Therapy, immunotherapy

•        Combination therapy