NEOPLASMSLecture 7

NEOPLASMSLecture 7

CARCINOGENESIS

1. Cell Rest Theory of Conheim – during development of an individual, some embryonic cells did not develop into mature cells. They become activated later on, grow rapidly into cancer.

2. Clone Theory – single cell has become abnormal and become the starting point of the tumor.

3. Group of Cell Theory – several cells become abnormal and become cancer cells.

4. Irritation Theory – some cells are damaged and become cancer cells.

5. Microbial Theory – begin to grow because of microorganisms , i.e., Epstein Barr Virus (EPV) and Ewing’s sarcoma

HOW NEOPLASM BEGINSHOW NEOPLASM BEGINS

1. Molecular Basis of Tumor

• Nonlethal genetic damage lies at the core of carcinogenesis

• Four classes of regulatory genes, protooncogene, cancer suppressor gene, regulated apoptosis gene, and DNA repair gene, are the principal targets of genetic damage.

• Carcinogenesis is a multistep process at both the phenotypic and genetic levels.

(1) Oncogenes and cancer

① Protein products of oncogenes

a. Growth factors

b. Growth factors receptors

c. Signal transducing proteins

d. Nuclear transcription proteins

e. Cyclones and cyclic-dependent kinases

② Activation of oncogenes

a. Point mutations

b. Chromosome rearrangements

Translocations

Inversions

c. Amplification

(Quoted from Robbins 《 Pathology Basis of

disease 》 )

Table Selected oncogenes their mode of

activation and associated human tumors Category Protooncogen

eMechanism Associated

Human Tumor

Growth Factors

PDGF-β chain 

Fibroblast growth factors

 Sis

Hst-1Int-2

 

Overexpression

OverexpressionAmplification

 

Astrocytoma Osteosarcoma Stomach cancerBladder cancerBreast cancerMelanoma

(2) Cancer suppressor genes

① Molecules that regulated nuclear transcription and cell cycle

Rb gene: 13q14, G1 × S

P53 gene: 17p13.1, related to 50% of human tumors

BRCA- l gene: 17q12-21,

BRCA-2 gene: 13q12-13

Molecules that regulated signal transduction

NF-1 gene: 17q11.2

APC gene: 5q21

(3) Genes that regulate apoptosis

Inhibit apoptosis: bc1- 2 gene (18q21), bc1-Xl

Favor apoptosis: bax, bad, bc1-xS

(4) Genes that regulate DNA repair

Humans literally swim in a sea of environmental carcinogens. Although exposure to naturally occurring DNA- damaging agents, such as ionizing radiation, sunlight, and dietary carcinogens, is common, cancer is a relatively rare outcome of such encounters.

This happy state of affairs results from the ability of normal cells to repair DNA damages and thus prevent mutations in genes that regulate cell growth and apoptosis.

In addition to possible DNA damage from environmental agents, the DNA of normal dividing cells is also susceptible to alterations resulting from errors that occur spontaneously during DNA replication.

Such mistakes, if not repaired promptly, can also push the cells along the slippery slope of neoplastic transformation.

The importance of DNA repair in maintaining the integrity of the genome is highlighted by several inherited disorders in which genes that encode proteins involved in DNA repair are defective.

Those born with such inherited

mutations of DNA repair proteins are at a greatly increased risk of developing cancer. Several examples are discussed next.

(5) Telomere and tumor

telomerase activity increased

in majority of human tumors.

Molecular Basis of Molecular Basis of Multistep Multistep

CarcinogenesisCarcinogenesis

2. Carcinogenic agents

A large number of agents cause genetic damage and inchece neoplastic transformation of cells

(1) Chemical carcinogens

Chemical carcinogenesis is also a multistep process.

① Initiation of carcinogenesis

Chemical carcinogens are diverse in structure, but they fall into one of two categories:

a. Direct-acting chemical carcinogenes

b. Indirect-acting chemical carcinogens (procarcinogenes),

Which require metabolic conversion in vivo to produce.

Ultimate carcinogens capable of transforming cells.

HP Solution Center.lnk

Both of them are highly reactive electrophiles that can react with nucleophilic (electron-rich) sites in the cells.

These reactions are nonenzymatic and result in the formation of covalent adducts between the chemical carcinogen and nucleotide in DNA.

The carcinogenic potency of a chemical is determined not only by the inherent reactivity of its electrophilic derivative, but also by the balance between metabolic activation and inactivation reactions.

If initiation occurs, carcinogen-altered cells could be heritable.

② Promotion of carcinogenesis Promoters earn induce tumors in initiated

cells, but they are nontumorigenic by them selves.

Prompters render cells susceptible to additional mutations by causing cellular proliferation.

CARCINOGEN

Electrophilic

intermediates

Binding to DNA:

Adduct formation

Permanent DNA lesion:

Initiated cell

Cell proliferaion:

Altered differentiation

PRENEOPLASTIC CLONE

MALIGNANT NEOPLASM

Additional

mutations

Metabolic activationExcretion

Proliferation

Normal cell

Cell death

DNA

repair

INITIATION

PROMOTION

(Quoted from Robbins

《 Pathology Basis of disease 》 )

STAGES OF CANCER

1. First Stage – intraepithelial, primary, carcinoma-in-situ

2. Second Stage – infiltrative, invasive, beyond the basement membrane

3. Third Stage – metastasis present, with secondary growth

Nomenclature• Although parenchymal cells determine their nature, the growth

and evolution of neoplasms are critically dependent on their stroma.

• Sometimes the parenchymal cells stimulate the formation of an abundant collagenous stroma referred to as desmoplasia.

• Papillomas are benign epitjelial neoplasms producing visible warty projections

• Syringomas are tumors of sweat glands• Trichoepithelioma are tumors arising from hair follicles• Hemartoma is a disorganized, benign tumor-like nodule that

contains differentiated cells and one cell type often predominates

• Carcinoma-in-situ is an epithelial tumor that has not yet penetrated the basement membrane and thus has no current chance of metastasis

• Choristoma is the presence of normal tissue in an abnormal location

• Hidradenomas are tumors arising from the vulva.

Basic Components of Tumor

There are 2 basic components of a tumor:1. Parenchyma – made up of proliferating

neoplastic cells. It is the component from which the tumor derives its name. It determines the biologic behavior of the tumor.

2. Stroma – is the supporting tissue of the tumor made u of CT, blood vessels and possibly lymphatics.

LIPOMALIPOMA

Choristoma• An ectopic rest of normal tissue is called a

choristoma.• Example is a rest of adrenal cells under the

kidney capsule• Analogously, aberrant differentiation may

produce a mass of disorganized mature specialized cells or tissue indigenous to the particular site, referred to as hamartoma.

• Types are: Salivary gland chorsitoma, cartilaginous choristoma,oral osseous choristoma, lingual thyroid choristoma, lingual sebaceous chorsitoma, and glial choristoma

CHORISTOMACHORISTOMA

HAMARTOMA

• Hamartoma is a developmental abnormality, tumor-like but non-neoplastic malformation consisting of a mixture of tissues normally found at a particular site.

• The commonest forms are those composed of blood vessels and those involving cells of the skin.

HAMARTOMAHAMARTOMA

Fibroma• A benign neoplasm arising from fibroblast• The tumor is discrete, encapsulated, spherical

ovoid nodules; about 15-20 cm particularly in the ovary, CT sheaths of nerves, and of muscles

• They are soft, rubbery, pliable masses.• They occur at any age, the cut surface discloses

a firm, white glistening surface• Microscopically, typical spindle cell fibrocytes

and fibroblasts are present.• Scant to large amounts of collages are found

between the fibroblasts

FIBROMAFIBROMA

Leiomyoma

• Also called “myoma” or “fibroid”.• Tumor is composed on intertwining bundles of

smooth muscle cells that more or less resemble of uninvolved myometrium.

• They are sharply circumscribed, unencapsulated but discrete, firm, gray-white masses with a characteristic whorled appearance on cut surface.

• This tumor may have an increase of the CT with dense hyalinization of the stroma

LEIOMYOMA-UTERUSLEIOMYOMA-UTERUS

CAPILLARY AND CAVERNOUS HEMANGIOMA

CAPILLARY AND CAVERNOUS HEMANGIOMA

PIGMENTED CELL NEVIPIGMENTED CELL NEVI

Types of Nevus• Intradermal nevus – is the common, flat or elevated

type composed of sheets of nevus cells, many of which contain melanin pigment.

• Compound nevus – exhibit features of both the intradermal and junctional nevus

• Blue nevus – is a smooth blue to blue-black lesion located in the CT and composed of spindle-shaped melanoblasts.

• Juvenile nevus – found in children that is histologically similar to malignant melanoma but is clinically benign

• Junctional nevus – appears to be dropping off from the overlying epithelium. It is of particular clinical significance, since it may undergo malignant transformation to malignant melanoma.

JUNCTIONAL NEVUSJUNCTIONAL NEVUS

COMPOUND NEVUSCOMPOUND NEVUS

HYDATIDIFORM MOLE - GROSS

HYDATIDIFORM MOLEHYDATIDIFORM MOLE

CHONDROMACHONDROMA

SCHWANNOMA or Neurilemmoma-Nerve

SCHWANNOMA or Neurilemmoma-Nerve

Adenoma

• Adenoma is the term applied to the benign epithelial neoplasm that forms glandular patterns

• Cystadenoma- those that form large cystic masses in the ovary

• Papillary cystadenoma – protrude into cystic spaces

• Papilloma – finger-like or warty projections from epithelial surfaces

• Desmoplasia – result when parenchymal cells stimulate the formation of an abundant stroma.

ADENOMA-CERVIXADENOMA-CERVIX

ADENOMA-TUBULAR TYPEADENOMA-TUBULAR TYPE

ADENOMA-VILLOUS TYPEADENOMA-VILLOUS TYPE

SEBACEOUS ADENOMASEBACEOUS ADENOMA

Question

A tumor composed of tissues representing all three embryonic germ layers commonly seen either in the ovary or in the testis is called

A. adenocarcinoma B. choristoma C. hamartoma D. teratoma E. mixed mesodermal tumor

ADENOMATOUS POLYPS COLI

APC is an inherited disorder characterized by the development of myriad polyps in the colon beginning in late adolescence or early childhood.

If untreated, the condition may lead to colon cancer.

The gene is located on chromosome 5.

HODGKIN’S LYMPHOMAHODGKIN’S LYMPHOMA• Also called benign

lymphoblastoma• Affects the lymph

nodes, spleen, liver and bone marrow

• Diagnostic feature in the RS giant cell (Reed-Sternberg giant cell)

REED-STERNBERG GIANT CELL – HODGKIN’S DISEASE

REED-STERNBERG GIANT CELL – HODGKIN’S DISEASE

Question

• On Southern Blot examination the DNA of a malignant tumor is found to have a clonal immunoglobulin gene rearrangement. From what type of cell is the tumor derived?

A. fibroblast

B. T lymphocyte

C. squamous epithelial cell

D. smooth muscle cell

E. B lymphocyte

FIBROADENOMA - FEMALE BREASTFIBROADENOMA - FEMALE BREAST

Fibroadenoma is the most coomon benignTumor of the breast. It developed as a

result of increased sensitivity to estrogen.Types of fibroadenoma:1. Intracanalicular fibroadenoma – the proliferating comonents into the

parenchymal channels are large polysoid masses

2. Pericanalicular fibroadenoma – the proliferating components are both the epithelium and CT stroma. Varieties of fibroadenocarcinoma:1. Scirrhous and medullary carcinomas2. Adenocarcinomas3. Intraductal carcinomas4. Paget’s disease of the nipple

FIBROADENOMAFIBROADENOMA

GIANT CELLTUMORGIANT CELLTUMOR

Giant cell Tumor or Osteoclastomaor Codmon’s Tumor

• This is a tumor of the epiphyses of long bones• Males and females are equally affected.• It involves the proximal tibia, distal femur and

distal radius. • It consists of destruction and replacement of

original bone matrix• Extensive production of new bone trabeculae• Filling of all cancellous bone spaces with

proliferating bone forming tumor cells.• It recur after curettage.

OSTEOMA OSTEOMA

MENINGIOMA WITH PSAMMONA BODIESMENINGIOMA WITH PSAMMONA BODIES

FIBROFOLLICULOMAFIBROFOLLICULOMA

Clinical Differences Between Benign and Malignant Neoplasms

Grow slowly Grow rapidly

Expansive growth Invasive growth

Usually encapsulated Not capsulated

Do not recur after careful removal

Recur after removal

Do not metastasize Often metastasize

Do not kill unless they compress vital organs

Do kill

Rarely show metastasis Often show necrosis and ulceration

No cachexia Cachexia and anemia

Histological Differences between Benign and Malignant Neoplasms

Benign Malignant

Consist of well-differentiated cells Consist of poorly-differentiated anaplastic cells

Cells are rather uniform in size and shape

Pleomorphism of cells

Nuclei take up stain normally Hyperchromatic nuclei

Few mitosis Numerous multipolar mitosis

Cells do not infiltrate Cells do infiltrate

Fairly good imitation of the arrangement of the tissue from which they are derived

Unsuccessful imitation of the tissue of the origin

MALIGNANT NEOPLASMSMALIGNANT NEOPLASMS

Differences Between Carcinoma and Sarcoma

Points of Differences Carcinoma Sarcoma

Cell origin Epithelial Mesenchymal

Cellular arrangement Alveolar or glandular Singly

Size Less in size More

Blood vessels Less More

Hemorrhages Less More

Necrosis Less More

Age incidence Older (may also occur in the young)

Younger (may also affect the older)

Mode of metastases Commonly through the lymphatics

Commonly through the blood but may also involve the lymphatics

Site of first metastasis Regional lymph nodes Lungs

ANAPLASIAANAPLASIA

ROUTES OF METASTASIS

• LOCAL INVASION

• LYMPHATIC SPREAD

• BLOOD OR HEMATOGENOUS SPREAD

• TRANSCOELOMIC SPREAD

• PERINEURAL SPREAD

• INTRAEPITHELIAL SPREAD

Pathways of Spread (Metastasis)

• Direct seeding of body cavities – most often involve the peritoneal cavity

• Transplantation – refers to the mechanical transport of tumor fragments by instruments of gloved hands during surgical procedures.

• Lymphatic spread – is the transport through the lymphatics and it is the most common pathway for the initial dissemination of carcinomas but sarcomas may also use these routes.

• Hematogenous spread – this pathway is typical with sarcomas but may also found in carcinomas.

Mechanisms of Cancer Invasiveness

• Physical pressure

• Reduced adhesiveness and cohesiveness of tumor cells

• Increased motility of tumor cells

• Loss of contact inhibition

• Release of destructive enzymes

• Reduced immune response inducing inflammatory reaction

ANAPLASIAANAPLASIA

PLEOMORPHISM AMD HYPERCHROMATISM-SCC

PLEOMORPHISM AMD HYPERCHROMATISM-SCC

OSTEOSARCOMAOSTEOSARCOMA

OSTEOSARCOMA-LONG BONEOSTEOSARCOMA-LONG BONE

LIPOSARCOMALIPOSARCOMA

CHONDROSARCOMACHONDROSARCOMA

BASAL CELL CARCINOMABASAL CELL CARCINOMA

ADENOCARCINOMA-PROSTATEADENOCARCINOMA-PROSTATE

MALIGNANT MELANOMA-SKINMALIGNANT MELANOMA-SKIN

DERMATOFIBROSARCOMA PROTUBERANS

DERMATOFIBROSARCOMA PROTUBERANS

SCC or Epidermoid carcinoma• Account for 90% of all malignant oral tumors• Arise at any site normally covered by stratified

squamous epithelium – skin, mouth, esophagus• Develop following conditions like leukoplakia, senile

keratosis, arsenic keratosis, burns, scar or foci of radiodermatitis

• Two Macroscopic types: 1. Papillary or exophytic types- appears as a warty outgrowth with an infiltrating base 2. Nodular or endophytic types – produces a hard, nodular mass beneath the surface and shows more raid infiltration and dissemination

SQUAMOUS CELL CARCINOMA-ORAL MUCOSA

SQUAMOUS CELL CARCINOMA-ORAL MUCOSA

SCC-EPITHELIAL PEARLSSCC-EPITHELIAL PEARLS

MULTIPLE MYELOMA

• Multiple myeloma is a malignant neoplasm of the bone marrow. The tumor, composed of plasma cells destroys osseous tissue, especially in flat bones, causing pain, fractures, hypercalcemia and skeletal deformities.

• Characteristically, there is hyperglobulinemia, Bence Jones proteinuria, anemia, weight loss, pulmonary complications secondary to rib fractures and kidney failures are present.

MULTIPLE MYELOMAMULTIPLE MYELOMA

Bone Lesions in MM

• The tumor cells produce lytic lesions in bone, especially in the skull and axial skeleton,

• Bone lesions:

- appear lucent on X-ray exam, with characteristic sharp borders, referred to as punched out lesions

- diffuse demineralization of bone (osteopenia)

- severe bone pain and spontaneous fractures

MULTIPLE MYELOMAOR PLASMA CELL MYELOMA

MULTIPLE MYELOMAOR PLASMA CELL MYELOMA

Ameloblastoma

• A highly destructive, malignant, rapidly growing tumor of the jaw.

• Also called adamantinoma.

• The histologic pattern is quite variable and recapitulates the enamel organ of the tooth.

• Microscopically, nests or cords of stratified squamous or columnar epithelium are embedded in a loose fibrous stroma.

AMELOBLASTOMA-MANDIBLE

ADAMANTINOMAADAMANTINOMA

Arrhenoblastoma

• An ovarian neoplasm whose cells mimic those in testicular tubules and secrete male sex hormome, causing virilization in females.

• Also called andreoblastoma or Sertoli-Leydig cell tumor

ARRHENOBLASTOMAARRHENOBLASTOMA

GLIOBLASTOMA MULTIFORMEGLIOBLASTOMA MULTIFORME

Effects of Malignant Neoplasms• Destruction of tissue• Hemorrhage• Starvation and weight loss• Pain• Anemia• Cachexia• Hormonal effects• Mechanical ressure and obstruction• Carcinomatous syndromes• Thrombotic complications• Muscular disorders (myopathies)• Neurological disorders• Endocrine disorders as Cushing’s syndrome, hypercalcemia,

hypoglycemia• Finger clubbing or hypertrophic osteoarthropathy• Achantosis nigricans (or gray-black raised atches on the skin and

oral mucous membranes, especially with gastric carcinoma

STAGING OF CANCERSTAGING OF CANCER

TNM• GRADING of cancer is a system for describing

the size and extent of spread of a malignant tumor, used to plan treatment and predict prognosis.

• T is used to represent the tumor size

• N denotes the regional lymph node involvement

• M indicates distant metastases

• Numeric subscripts-in each category indicates the degree of dissemination

TNM

• T1N0M0 - is a small, localized tumor

• T2N1M0 - is larger primary tumor that has extended to regional nodes

• T4N3M3 – is a very large lesion involving regional nodes and distant sites

TNM STAGINGTNM STAGING

• Next Meeting:

• Quiz on Neoplasms:

Benign & Malignant Neoplasms