introduction to neoplasia

INTRODUCTION TO

NEOPLASIA

Nomenclature of various

growth processes (“Plasias”)

• Hyperplasia

• Metaplasia

• Dysplasia

• Neoplasia

• Desmoplasia

Metaplasia

an adaptive substitution of one type of adult tissue to another type of adult tissue

under stress a more vulnerable type of tissue will be replaced by another more capable of withstanding stress

Dysplasia

An abnormality in cell size,

appearance, with or without a

disorganized growth pattern

Neoplasia

A disease of cells characterized by alteration of normal

growth regulatory mechanisms

Desmoplasia

The formation and proliferation of connective tissue in response to neoplastic growth

Neoplastic progression

• Benign or malignant neoplasms can acquire increasingly aggressive features

• Most malignant neoplasms arise de novo

• Some malignant neoplasms are thought to be preceded by preneoplastic conditions

Definitions

Neoplasm - (new growth) abnormal mass of tissue, the growth of which exceeds and is uncoordinated with the normal tissues

Tumor - a non-specific term meaning lump or swelling. Often syn. for neoplasm

Cancer - any malignant neoplasm or tumor

Metastasis - discontinuous spread of a malignant neoplasm to distant sites

Cancer (L. Crab)

• Any malignant growth of cells (clonal)

• Second most common cause of death in

US

• One in 3 Americans will die of cancer

Gross features Microscopic features

Classification - Approach

Terminology which is used to describe a

mass is based on the clinical, gross and

microscopic features-which in

combination are a reflection of the

predicted/expected biologic behavior

Benign Malignant ?

Classification Criteria

• Growth Characteristics

• Rate of Proliferation and Cell Death

• Differentiation

• Metastasis

Classification Criteria and

Associated Biologic Behavior

Characteristics Benign Malignant

Growth pattern expansive infiltrative

rate of slow fast

growth

differentiation nl, good atypical, poor

metastasis absent typical

Growth pattern

Benign Malignant

Rate of Growth

Rapid

Classification - Differentiation

• According to biologic behavior and

histogenesis or cellular features

– Benign

• Adenoma - benign epithelial neoplasm

• Lipoma -benign mesenchymal neoplasm

– Malignant

• CARCINOMA - malignant epithelial neoplasm

• SARCOMA - malignant mesenchymal neoplasm

• LYMPHOMA/LEUKEMIA - malignant neoplasm of

lymphoid cells

Classification According to

behavior

Fibroadenoma Adenocarcinoma

Classification According to

Cellular Features Squamous-

Eosinophillic (pink)

abundant cytoplasm

Keratin, keratin pearl

Hyperchromatic

(dark) nucleus

Lack of differentiation

Intercellular clear spaces

Normal epithelium

Squamous cell carcinoma

Lung Cancer

x-ray Squamous carcinoma

Classification According to

Cellular Features Adenocarcinoma Normal

Gland-like spaces

Mucin production,

secretory activity

Colon Cancer

X-ray Gross Microscopic

Classification According to

Cellular Features

Lymphoma

Classification According to

Cellular Features

Recapitulation of normal features

Differentiation along mesenchymal pathways

Osteogenic sarcoma

Invasion and Metastasis

• Characteristics that are unique to

malignant neoplasms (cancer)

• The major cause of morbidity and

mortality

Invasion

• Associated with activated motility

and local tissue independence in

vitro

• Balance between tissue destruction

and synthesis

• Cell surface and extracellular matrix

play important roles

Metastasis

• Require acquisition of additional

tumor characteristics beyond those

necessary for invasion

• Multiple lesions

• Organ specificity

Metastasis

Mechanisms of Spread:

•Hematogenous

•Lymphatics

Other mechanisms of

spread

• Direct extension

• Seeding

• Surgical or procedural

transplantation (iatrogenic)

Prognosis

• Prediction of Outcome

– Criteria are different for each cancer type

– Grade, stage, histology routine criteria

– Patient characteristics are important

– Treatment considerations critical

Prognostic Factors

• Grade

• Stage

• Tumor type

• Biomarkers (slide based and

molecular techniques)

Cancer Grade

• Alternate term “tumor grade”

• Based on microscopic features

(cytology or histology)

low grade moderate high

Cancer Stage • Reflects degree of spread, for an

individual cancer patient

• Assigned at the time of diagnosis, may be

updated as patient progresses T Tumor characteristics

N Nodal involvement

M Metastasis

Morbidity and Mortality • Metastases

• Rupture into major vessels, structure

• Starvation

• Infection

• Compression of vital organs

• Organ failure

Summary

• Cancer is synonymous with malignant

neoplasia

• Precursor/precancerous lesions exist

• Invasion and metastasis are the hallmark

of malignancy

• Cancer typing and subtyping is pre-

requisite for patient treatment