Neoplasia Lecture Notes

image

Neoplasia Defintions

– Neoplasm: mass of tissue that grows excessively & keeps growing even if you remove the stimulate that started it off.

– Tumor=neoplasm

– Benign tumor= innocent – acting tumor

– Malignant tumor= evil – acting tumor

 

General characteristics of Neoplasia

Benign tumors

– small

– slow growing

– Non invasive

– well differentiated

– stay localized

 

Malignant tumor

– large

– fast growing

– invasive

– poorly differentiated

– metastasize

– The only indisputable equality of malignancy is metastasis

– Benign tumor can’t metastasize , Malignant tumors can.

– If it is metastatic , it must be Malignant .

E.g.

– if lung cancer spreads to liver , the cancer cells in the liver are lung cancer cells . The disease called metastatic lung cancer “it is not liver cancer’’

– primary site = Lung

– Secondary site = Liver

– Usually designated by adding ‘’-oma’’ to cell type .

– adenoma- Benign tumor arising from glandular cells.

– leiomyoma- Benign tumor arising from smooth muscle cells .

– chondroma- Benign tumor arising from chondrocytes .

– papilloma-has finger like projections .

– polyp- projects upward , forming a lump

– cystadenoma-has hollow spaces ‘’cysts’’ inside.

 

Malignant Tumors

– carcinomas – arise in epithelial tissue.

– adenocarcinoma- Malignant tumors of glandular cells

– squamous cell carcinoma- Malignant tumor of squamous cells.

– Sarcomas – arise in mesenchymal tissue .

– chondrosarcoma- Malignant tumor of chondrocytes.

– angiosarcoma- Malignant tumor of blood vessels.

– rhabdomyosarcoma- Malignant tumor of skeletal muscle cells .

 

Mixed Tumor

Mixed Tumor show divergent differentiation.

e.g. -pleomorphic adenoma-glands+fibromyxoid stroma

– fibroadenoma- glands + fibrous tissue .

– Not to be confused with teratomas.

Confusing Terms

– Malignant tumor that sound benign .

– lymphoma. -mesothelioma.

– melanoma. -seminoma.

– Non-tumors that sound like tumors:

– hamartoma-mass of disorganized indigenous tissue.

– choristoma-hetero topic rest of cells.

– Names that seem to come out of now here:

– Nevus -leukemia

– hydatidiform mole

image

 

Tumors characteristic

• Differentiation and anaplasia

– Differentiation= how much the tumor cells resemble their cells of origin

– weel differentiated – closely resemble normal countepart

– moderately differentiated – sort of resemble normal countepart

– poorly differentiated – doesn’t resemble normal countepart

• Benign Tumors are usually well differentiated

• malignant Tumors can show any level of differentiated

 

Anaplasia

– Anaplasia = a state of complete un –Differentiaion

– literally “ to form ( – plasia ) backword ( ana – )

• Misnomer cells don’t differentiate

• just mean cells are very poorly differentiated

• Almost always indicates malignancy

Anaplastic cells show:

• pleomorphism

• hyperchromatic , large nuclei

• bizarre nuclear shapes , distinct nucleoli

• losts of mitosis , and atypical mitosis

• architectural anarchy

 

Dysplasia

– Dysplasia = disorderly ( dys – ) growth ( – plasia )

– Dysplasia is used to describe disorderly change in non- neoplastic epithelial cells

• Graded as mild , moderate , or sever

– mild – moderate : usually reversible

– sever : usually progresses to carcinoma in situ ( CIS)

– Next step after CIS : invasive carcinoma

Dysplastic cells show:

• Pleomorphism

• hyper chromatic , large nuclei

• losts of mitosis

• architectural anarchy

image

Rate of growth

Generalization

• Malignant tumors grow faster than benign ones

• poorly differentiated tumors grow faster than Well differentiated one

Growth is dependent on :-

– blood supply

– hormonal factor

– emergence of aggressive sub – clones

Metastasis

• Metastasis = development of secondary tumor implants in distant tissues.

• Half of all patients with a malignancies have metastasize at the time of diagnosis.

Metastasis depends on:
– Type of tumor.
– Size of tumor.
– Degree of differentiation of tumor.

• Three ways tumor metastasize:
– Seeding.
– Lymphatic spread.
– Hematogenous spread.

• Lymphatic spread:
– Tumor spreads to local lymph nodes
– Sentinel lymph node first.
– Moves through thoracic duct.
– Empties into subclavian vein.
– Carcinomas like to spread this way.

• Hematogenous spread:
– Veins are easier to invade than arteries.
– Liver and lungs are most common metastatic destinations.
– Some tumor like other sites better:

  • Prostate à Bone
  • Most lung cancer à adrenals, brain

– Sarcomas like to spread this way [but so do carcinomas].

Epidemiology on Neoplasms

• Cancer incidence.

• Environmental variables.

• Age.

• Heredity.

• Acquired preneoplastic syndromes.

Cancer incidence

• 1.4 million new cases of cancer 2006 usa.

• 565.000 death from cancer 2006 usa.

• Cancer is 2nd leading cause of death after heart.

• Most common cancers:
* men: prostate
* women: breast

• Deadliest cancers:
* men and women: Lung

• Death rate have changed over past 4 years.

• Decrease in death rate:

– Cervical cancer ( pap smear).

– Colon cancer ( earlier detection).

– Breast cancer (earlier detection).

– Lung cancer in men (less smoking).

– Some type of leukemia ( new treatment).

• Increase in death rate:

– Lung cancer in women ( more smoking)

Environmental variables

• Breast cancer death rate in US is 5x than japan.

• Stomch cancer death rate in japan is 7x than US.

• Liver cancer infrquent in US, common in africa.

• Probably due to environmental factor(not hereditary )factor .

• Most sporadic cancer are caused by environmental factor.

Environmental carcinogen

• Sun light : skin cancer.

• Smoking: lung cancer.

• Alcohol: liver& breast cancer.

• HPV: cervical carcinoma.

Age

• Cancer is most frequent at two extremes of age

• Elderly
* frequency of cancer increase with age
* most cancer deaths occur between 55-75 .

• Children
* 10% of all childhood deaths.
* leukemia/lymphoma, CNS tumors, sarcoma.

Heredity

• Three categories of heredity cancer:
1. Inherited cancer syndrome.
2. Familial cancer.
3. Syndrome of defective DNA repair.

Inherited cancer syndrome

• Dominantly inherited.

• Retinoblastoma.

• Familial polyposis coli

Familial cancer

• Most common sporadic cancers have familial formation.

• Breast, colon, brain, ovary.

• Occur earlier are often deadlier.

Syndrome of defective DNA repair

• Recessively inherited.

• Xeroderma pigmantosum.

Acquired preneoplastic syndromes

• Persistent regeneration cell replication
* chronic skin fistula – squamus cell carcinoma
* cirrhosis – liver cancer

• Hyperplastic and dysplastic proliferation
* Atypical endometerial hyperplasia àendometrial cancer
* Dysplastic bronchial mucosa à lung cancer.

• Chronic atrophic gastritis à stomach cancer.

• Chronic ulcerative colitis à colon cancer.

• Leukoplakia à squamous cell

Related posts:

Posted in General, Oncology Tagged with: , , , , , , , , , ,

FaceBook Page

(function(i,s,o,g,r,a,m){i[\'GoogleAnalyticsObject\']=r;i[r]=i[r]||function(){ (i[r].q=i[r].q||[]).push(arguments)},i[r].l=1*new Date();a=s.createElement(o), m=s.getElementsByTagName(o)[0];a.async=1;a.src=g;m.parentNode.insertBefore(a,m) })(window,document,\'script\',\'https://www.google-analytics.com/analytics.js\',\'ga\'); ga(\'create\', \'UA-69237529-7\', \'auto\'); ga(\'send\', \'pageview\');