NEOPLASIA

• Definitions of terms used in neoplasia• Nomenclature of tumors• Characteristics of benign & malignant tumors• Routes of metastasis• Epidemiology of CANCER• The molecular basis of neoplasia• Carcinogenesis• Tumor immunity• The clinical effects of tumors• Tumor grading and staging• The laboratory diagnosis of neoplasia

GENERAL TERMS USED

• Neoplasm New growth of cells producing a mass• Benign neoplasm= Limited new growth without

invasion or spread• Malignant neoplasm= invasive growth that also

spreads• Carcinoma : Malignant tumor of epithelial cells• Sarcoma : Malignant tumor of connective tissue cells• Lymphoma

• Cancer is a general term for all malignant growths of whatever type• Tumor may be used instead

of neoplasm but the term is not accurate• Oncology: study of cancer in all its

aspects

NEOPLASM

• Abnormal mass of tissue, the growth of which EXCEEDS and is UNCOORDINATED with that of of the normal tissues, and PERSISTS in the same manner even AFTER CESSATION of the stimulus which produced the change

• A neoplasm develops from a single transformed cell !!!

• Fundamental to the origin of all neoplasms are heritable (genetic) changes that allow excessive and unregulated proliferation that is independent of physiologic growth-regulatory stimuli.

FEATURESOF TRANSFORMED CELL

•Persistent & useless•Uncontrolled growth*• Immortal• Transplantable

• This may arise fromEndoderm

• Mesoderm• Ectoderm• Epithelial cells may arise from any of the

above• Connective tissue is from mesoderm

Classification of tumors

• Cell of origin• Behavior of tumor: Benign or malignant • Appearance of the tumor: Solid/cystic• Degree of differentiation

CLASSIFICATION

• Benign tumors• Malignant tumors • Mixed tumors• Tetatoma of both benign and

malignant

• Tumors, benign and malignant, have two basic components

• (1) the parenchyma, made up of transformed or neoplastic cells, and

• The parenchyma of the neoplasm largely determines its biologic behavior, and the component from which the tumor derives its name

• (2) Stroma the supporting, host-derived, non-neoplastic made up of connective tissue, blood vessels, and host-derived inflammatory cells.

• Stroma, it carries the blood supply and provides support for the growth of parenchymal cells.

Sebaceous cyst

Structure of Neoplasm

• Parenchymal cell• Stromal ( supporting cell )• Degree & type of stromal cells may contribute to

the appearance of tumors• If there is stromal proliferation• hardness of the tumor• Scirrhous tumor• Desmoplasia e.g.carcinoma of breast,

pancreas..etc

• If there is lack of many stromal cells, the tumor may be soft or cystic.

• This feature may be included in the name of the tumor..e.g Cystadenoma of ovary

• Poorly differentiated cyst adenocarcinoma of ovary

• Moderately differentiated scirrhous carcinoma of breast

•

Serous cyst adenoma of ovary

Scirrhous carcinoma of breast Desmoplasia

Benign tumors

• Benign tumors are(microscopic and gross characteristics) are

• Innocent• Localized• Cannot spread to other sites• Easy for surgical resection• Survival of the patient is fair.• But in certain tumors it can be serious.

Malignant tumors

• 1.Are cancers, 2 They are not localized 3.They invade, destroy the adjacent structures. 4.Distant metastasis 5. Can cause death

Nomenclature – Benign Tumors

• -oma = benign neoplasm• Microscopic and Macroscopic

classification.• Mesenchymal tumors–Chrondroma: cartilaginous tumor–Fibroma: fibrous tumor–Osteoma: bone tumor

• Epithelial tumor– adenoma: tumor forming glands–papilloma: tumor with finger like

projections–papillary cystadenoma: papillary and cystic

tumor forming glands–polyp: a tumor that projects above a

mucosal surface

Benign epithelial tumors

• Adenoma• glandular epithelium tumor often producing a

secretion e.g.(mucin) which may be intraepithelial or intraluminal

• Papilloma epithelial tumor forming finger like projections from epithelia surface with a connective tissue core

• Polyp a tumor projecting from the mucosal surface of a hollow organ

• Adenoma of benign arise in solid organs• Liver, Thyroid and kidney typically glandular

pattern• Since they are benign they remain• Discrete pushing compressing the surrounding

tissue and remain localized also they show tissue of origin

Malignant tumors

• Malignant neoplasms arising in mesenchymal tissue or its derivatives are called sarcomas

• A cancer of fibrous tissue origin is a fibrosarcoma, and a malignant neoplasm composed of chondrocytes is a chondrosarcoma.

Nomenclature – Malignant Tumors• Sarcomas: mesenchymal tumor–chrondrosarcoma: cartilaginous

tumor–fibrosarcomama: fibrous tumor–osteosarcoma: bone tumor

• Carcinomas: epithelial tumors–ADENOCARCINOMA: gland forming

tumor–SQUAMOUS CELL CARCINOMA:

squamous differentiation–undifferentiated carcinoma: no

differentiation–note: carcinomas can arise from

ectoderm, mesoderm, or endoderm

• Malignant neoplasms of epithelial cell origin are called carcinomas

• Carcinomas that grow in a glandular pattern are called ADENOCARCINOMAS, and those that produce squamous cells are called squamous cell carcinomas.

• Squamous cell carcinoma • Example-. skin, mouth cervix, bronchus.etc• Adenocarcinoma from glandular origin• Example-.G.I.T., endometrium ,breast, kidney,

thyroid..etc

• SARCOMA :• Prefix (origin)+ suffix (sarcoma)

e.g.Osteosarcoma,liposarcoma,angiosarcomaleiomyosarcoma,rhabdomyosarcoma

MIXED TUMOR

• FIBROADENOMA• IT HAS DUCTAL ELEMENT • ADENOMA• ALSO EMBEDED IN LOOSE FIBROUS TISSUE

FIBROMA• TUMORS OF THE SALIVARY GLAND• PLEOMORPHIC ADENOMA

Fibroadenoma

• Fibroadenoma is the most common benign (noncancerous) growth in the breast. If it is diagnosed on needle biopsy and the mammographic finding is consistent with a fibroadenoma, it is typically simply followed, with no additional excision. In some instances it may be removed for cosmetic reasons. 

• A patient's age determines the preferred imaging method. In general, ultrasonography (US) is preferred if a palpable mass is found, if a patient is younger than 30 years, or if the patient is not pregnant, Mammography and US are both useful if the patient.

Fibroadenoma breast mammogram

TERETOMA

• Teratomas originate from totipotential stem cells• which contains recognizable mature

or immature cells or tissues representative of more than one germ-cell layer and sometimes all three.

BENIGN

•Mature teratoma•Dermoid cyst

MALIGNANT

•Immature teratoma•Terato carcinoma

• Teratomas originate from totipotential stem cells such as those normally present in the ovary and testis and sometimes abnormally present in sequestered midline embryonic rests

Testicular teratoma

Seminoma testis

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© 2005 Elsevier

• Aberrant differentiation (not true neoplasms)–Hamartoma: disorganized mass of

tissue whose cell types are indiginous to the site of the lesion, e.g., lung–Choriostoma: ectopic focus of

normal tissue (heterotopia), e.g., pancreas, perhaps endometriosis too

BENIGN SOUNDING DESIGNATIONS• Misnomers–Hepatoma: malignant liver tumor–Melanoma: malignant skin tumor–Seminoma: malignant testicular

tumor–Lymphoma: malignant tumor of

lymphocytes

Hamartoma

• Clinical presentation• Pulmonary hamartomas are usually asymptomatic and

found incidentally when imaging the chest for other reasons. It can occasionally present with haemoptysis, bronchial obstruction and cough (especially endobronchial types) .

• Pathology• Hamartomas may be chondromatous or leiomyomatous

(the former being more common) or a mixture. They are unencapsulated, lobulated tumours with connective tissue septa

Dysplasia• Literally means abnormal growth• Malignant transformation is a multistep process• In dysplasia some but not all of the features of malignancy are

present, microscopically

• Dysplasia may develop into malignancy– Uterine cervix– Colon polyps

• Graded as low-grade or high-grade, often prompting different clinical decisions

• Dysplasia may NOT develop into malignancy• HIGH grade dysplasia often classified with CIS

Natural History Of Malignant Tumors

1. Malignant change in the target cell, referred to as transformation

2. Growth of the transformed cells 3. Local invasion4. Distant metastases.

Benign vs Malignant Features

Feature Benign Malignant

Rate of growth slow. Mitoses few and normal

Variable. Mitoses more frequent and may be abnormal

Differentiation Well differentiated Some degree of anaplasia

LOCAL INVASION

Cohesive growth. Capsule & BM not breached

Poorly cohesive and

infiltrative!Metastasis Absent May occur

Benign vs Malignant

• Rate of growth– Most benign tumors grow slowly while most

cancers grow fast• Many exceptions

– Rate of growth for malignant tumors correlates with degree of differentiation

– Despite rapid growth, cancers usually take years to become clinically apparent

– Rapid growth may lead to necrosis

Benign vs Malignant

• Local invasion– Benign neoplasms do not have the capacity to

invade – Invasion is a characteristic of malignancy– Benign neoplasms often develop a fibrous capsule

Benign vs Malignant

• Metastasis– Metastases are secondary, remote implants of

tumor– Metastatic spread is the most important hallmark

of malignancy– Cancers differ in their ability to metastasize– Methods of metastasis:• Seeding• Lymphatic spread• Hematogenous spread

Epidemiology

• The study of the relationships of various factors determining the frequency and distribution of diseases in the human community

• Contributes to understanding of risk factors and the origin of cancers

• Smoking – Lung cancer• Fatty diets – Colon cancer

Epidemiology

• Geographic and environmental factors– Breast cancer – Death rates 4-5x higher in US and

Europe than in Japan– Stomach cancer – Death rates 7x higher in Japan

than in the US– Hepatocellular carcinoma – Uncommon in US, one

of the most common and lethal cancers in some African populations

• Most geographic patterns related to environmental exposures

Epidemiology

• Age– Frequency of cancer increases with age with peak

between ages of 55 and 75– Increased accumulation of somatic mutations

• Heredity– 5-10% of cancers

• Acquired preneoplastic disorders– Dysplasia, colonic adenoma