Tumour BiologyTumour BiologyOGUNLADE.TOGUNLADE.T

OUTLINE INTRODUCTION CLASSIFICATION NOMENCLATURE PICTURES

INTRODUCTION

All new growths are not neoplasms:  New growths also exist in: 1.Embrogenesis 2.Regeneration and repairs 3.Hyperplasia 4.Hormonal stimulation

ALL THESE PROCESSES ARE CONTROLLED AND COORDINATED

INTRODUCTION

“Willis” definition of Neoplasia - (new growth) abnormal mass of tissue, the growth of which exceeds and is uncoordinated with the normal tissues and continues to grow even after the cessation of the stimulus that evoked the initial response

General Features of Neoplasia

ORIGIN: stem cells {tumour-initiating cells}

Genetic disorder/mutation Heritable Monoclonal Carcinogenic stimulus Autonomy Irreversible Differentiation

6Ps of Neoplasia

CLASSIFICATION NEOPLASM

BENIGN MALIGNANT

BIOLOGICAL BEHAVIOR OF THE TUMOR.

BENIGN TUMORS Have a relatively innocent microscopic and gross

characteristic Localized without invasion(Expansive) Well differentiated: closely resembles the normal cell of

origin Capsulated No metastasis Mostly slow rate of growth Prognosis is good: after surgery

MALIGNANT TUMORS Invade or infiltrate into the adjacent tissues or structures Metastasize EXCEPTION: Basal cell carcinoma of the skin Glioma –Tumor arising from astrocytes, oligodendrocytes,

ependymal cells, and plexus epithelial cells {CNS} Differentiation: varies{well, moderate or poorly} Well differentiated-adenocarcinomas of colon Moderately differentiated Poorly differentiated Anaplasia Prognosis: Most result death.

DIFFERENTIATION

Benign vs Malignant

Characteristics Benign Malignant

Growth pattern Expansive Infiltrative

Rate of growth Slow Fast

Differentiation Good Atypical, poor

Metastasis Absent Usually Present

ANAPLASIA Lack of differentiation (both structural and functional)

Microscopic Features of Anaplasia Pleomorphism: variation in the size and shape of cells and cell nuclei

(large to extremely small cells) Abnormal nuclear morphology {hyperchromatic nuclei, Nuclear

shape and size is variable,} MITOSES: mitotic figures, Atypical mitotic figures Nuclear cytoplasmic (N : C) ratio: enlarged nuclei{1:1} Loss of polarity: Orientation of cells to one another loss of normal polarity, markedly disturbed orientation (architecture)

of tumor cells. Bizarre cells, including tumor giant cells

The more anaplastic a tumor is, the more aggressive it is

Microscopic Features of Anaplasia

Rates of GrowthFactors Determining the Rate of

GrowthDegree of differentiationHormonal stimulationAdequacy of blood supplyDoubling time of tumor cells

Microscopic Components of Neoplasms All tumors have two components

Parenchyma Represents tumor proper; the growth of the tumor is due

to proliferation of these cells neoplastic cells

Stroma Provides the framework, blood supply and nutrition for the

parenchymal cells

Carcinoma of breast

Desmoplasia Formation of abundant collagenous stroma Stimulated by parenchymal cells

Ex: Schirrous. ca of breast Linitus plastica (ca stomach) Carcinoma prostate

Scirrhous carcinoma of breast/Linitus plastica

NOMENCLATUREBENIGN

Generally named by attaching the suffix “oma” to the cell of originEXCEPTIONS:MELANOMA, LYMPHOMA, SEMINOMA which are all malignant tumors.Adenoma: E.g Adrenocortical adenoma, Follicular adenoma of thyroid, Adenomatous polyp of the colonPapilloma: Example: squamous papillomaCystadenoma: tumor forming large cystic masses. Example: Serous cystadenoma of ovaryPapillary cystadenomaPolyp: produces visible projection above a mucosal surface and projects into the lumen.Maybe benign or malignantE.g Polyp of stomach or intestine.

BENIGN

Morphological (gross/microscopic) appearance of some benign epithelial tumors

MALIGNANT

They are termed as carcinoma or sarcoma depending on the parenchymal cell of origin.

Epithelial-carcinoma Mesenchymal-sarcoma

OTHERS EPONYMOUSLY NAMED TUMORS MIXED TUMORS: derived from a single germ layer but show divergent

differentiation along two lineages E.g Mixed tumor of salivary gland (pleomorphic adenoma) TERATOMAS: They are special types of mixed tumors derived from

totipotent germ cells Sites:Ovary,Testes and mediastinum Teratomas include: Benign/mature teratoma: ovarian cystic teratoma Immature/malignant teratoma: consists of immature or less well-

diff erentiated tissue . Monodermal/highly specialized: struma ovarii and carcinoid

developing in ovary Teratoma with malignant transformation: SCC developing in a

teratoma of testis.Divergent differentiation – more than one neoplastic cell type but derived from one germ cell layer

OTHERS cont’d HAMARTOMAS: Disorganized Benign appearing, non-neoplastic

overgrowth of tissue. e.g Pulmonary chondroid hamartoma with disorganized, but

normal cartilage, bronchi, and vessels CHORISTOMA: Normal tissue in an abnormal site e.g small

nodular mass of normally organized pancreatic tissue in the submucosa of the stomach, duodenum, or small intestine

EMBRYONAL TUMORS (BLASTOMAS): tumor type developed only in children (usually <5 yrs of age),microscopically resemble embryonic tissue of the organ in which they arise

Cancer Grade Grading is to establish the level of tumour cell differentiation from

the normal surrounding cell Shows how aggressive tumour cells are from the normal cells from

which it came from well differentiation (mildly aggressive tumour cell but close to

normal cell), moderate differentiation (moderately aggressive tumour cells

compared to normal cells), poorly differentiated (severely aggressive tumour cells compared

to normal cells).  

Grading of Malignant Neoplasms

Grade Definition

I Well differentiated

II Moderately differentiated

III Poorly differentiated

IV Nearly anaplastic

Cancer Stage Staging of tumour is based upon the extent of metastasis. the TNM system

BASED ON: Tumour size (T)=T0 to T4 Extent of spread to the lymph nodes (N)=N0 to N3 Presence or absence of distant metastases (M)=M0 to M1

Staging of Malignant Neoplasms

Stage Definition T0 In situ, non-invasive (confined to epithelium)

T1 Small, minimally invasive within primary organ site

T2 Larger, more invasive within the primary organ site

T3 Larger and/or invasive beyond margins of primary organ site

T4 Very large and/or very invasive, spread to adjacent organs

N0 No lymph node involvement

N1 Regional lymph node involvement

N2 Extensive regional lymph node involvement

N3 More distant lymph node involvement

M0 No distant metastases

M1 Distant metastases present

Opened cystic teratoma of the ovary

Liposarcoma (skin)

Chondrosarcoma

Papillary carcinoma of the bladder

Carcinoma of the prostate

Teratoma of trestis and ovary

Sacrococcygeal teratoma

Loss of polarity

Differentiation and anaplasia Two thyroid tumors

Follicular carcinoma Anaplastic carcinoma

Growth patternBenign

MalignantMalignant

Leiomyomas and breast carcinoma

Benign tumors - micro

LipomaLipoma LeiomyomaLeiomyoma

AdenomaAdenoma

Local invasion

Hepatic adenomaHepatic adenoma Hepatocellular carcinomaHepatocellular carcinoma

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