NEOPLASIA

• Neoplasia – new growth

• New growth produced – TUMOUR / NEOPLASM

• However all new growths – NOT a neoplasm

• Also can occur in• Embryogenesis• Regeneration and Repair• Hyperplasia• Hormonal Stimulation

Definition

• Mass of tissue formed as a result of Uncontrolled, Excessive, Abnormal, Autonomous and Purposeless proliferation of cells

• Science of study of Neoplasms – Oncology• Oncos = tumour, Logos = study

Types

• Benign • Malignant

• Common term for malignant tumours – CANCER

• Term CANCER means CRAB – “since it sticks to the part like a crab”

• Benign• Slow Growing• Localised• No much difficulty to the Host

• Malignant• Rapidly growing• Spread throughout the body• Much difficulty to the host

Components

• 2 Basic components of tumours• Parenchymal cells• Stromal cells

• Parenchyma (Parenchymal cells)• proliferating tumour cells • Determines the nature and evolution of the

tumour

• Supportive Stroma(Stromal cells)• Fibrous connective tissue and blood vessels• Framework on which parenchyma present

Nomenclature

• Based on the parenchymal component comprising them

• Usually, Benign – ‘oma’ is the suffix

• Malignant tumours• Epithelial – Carcinoma• Mesenchymal - Sarcoma

Exceptions

• Some cancers – Highly undifferentiated cells • Hence called ‘Undifferentiated malignant

tumours’

• Exceptions for ‘oma’ rule:-• Carcinoma of Melanocytes – MELANOMA

Carcinoma of Hepatocytes – HEPATOMA• Malignancy of Lymphoid – LYMPHOMA• Malignancy of Testis - SEMINOMA

Special Categories

• Mixed tumours • 2 types of tumours present in the same

tumour

Eg:- Adenosquamous carcinoma – EndometriumAdenoacanthoma – EndometriumCarcinosarcoma- Thyroid

• Collision Tumour – Morphologically two different tumour in the same organ not mixing with each other

• Mixed tumour of salivary gland (Pleomorphic adenoma)

• Benign tumour with epithelial and mesenchymal elements

Teratomas

• Totipotent cells – All three germ layers• Endo/meso/ ecto derms

• 2 types• Benign – Mature• Malignant – Immature

Most common sites – Testis/ Ovary (gonadal teratomas)

Blastomas

• Embryomas• Arise from embryonal components normally

forming the organs & tissues of embryogenesis

• Frequent in < 5 yrs age group• Eg:- Neuroblastoma• Nephroblastoma(Wilms’ tumour)• Hepatoblastoma, Medulloblastoma

Hamartoma

• Benign• Mature but disorganised tissues indigenous to

the particular organ

• Eg:- hamartoma of lung – Mature cartilage, smooth muscle and epithelium

Choristoma

• Ectopic islands of normal tissue• Generally a heterotopia – not a true tumour

Characteristics of Tumours

• Rate of growth• Clinical & Gross features• Microscopic features• Local Invasion• Metastasis

Rate of Growth

• 2 main factors• Rate of division and destruction of cells• Degree of Differentiation

Rate of Division/Destruction

• Malignant cells – Increased mitotic rate• Decreased death rate

• Don’t follow normal cell cycle control – immortal

• If division is high, centre of tumour – less nourishment leading to ischaemic necrosis

Degree of differentiation

• Rate of growth directly proportional to Degree of Differentiation

• Poorly differentiated – Aggressive growth• Well differentiated – Slow growth

Regulation of tumour growth

• Due to Growth factors like• EGF – Epidermal growth factor• FGF- Fibroblast growth factor• PDGF- Platelet derived growth factor• CSF – Colony stimulating factor• TGF – Transforming growth factor

• Also Interleukins play a major role

Clinical and gross features

• Clinically • Benign – slow growing

• Depending on location• Asymptomatic – subcutaneous lipoma• Symptoms – Meningioma of CNS

• Malignant tumours• Rapidly growing• Invade superficially or into deeper structures• Spread to distant tissues• Systemic features – anorexia, weight loss,

tiredness

Grossly

• Features like

• Colour• Texture• Consistency helpful in distinguishing

• Malignant tumours grossly may appear fungating, ulcerative, papillary, hemorrhagic, infiltrating

• Benign • Well circumscribed/ encapsulated• Freely movable and firm

• Malignant• Poorly circumscribed• Fixed and irregular in shape• Secondary changes like hemorrhage & infarction

Microscopic features

• Greatest importance for classifying

• Features to be appreciated • Microscopic pattern• Cytomorphology• Tumour angiogenesis and stroma• Inflammatory reaction

Microscopic Pattern

• Variety of patterns

• Epithelial – sheets, cords, acini, columns– Solid or papillary

• Mesenchymal – Interlacing bundles, whorls, fascicles– Usually separated by intercellular matrix

• Mixed – Teratoma/ Pleomorphic adenoma

Cytomorphology of Neoplastic Cells

• Differentiation– Extent of resemblance to the normal tissue– Well/ Poorly differentiated

• Anaplasia– Lack of differentiation– Characteristic feature of Malignancy

Indicators of Anaplasia

• Basal Polarity– Normally nucleus oriented towards basement

membrane• Pleomorphism– Variation in size and shape of cells

• N/C ratio– Nuclear cytoplasmic ratio

• Anisonucleosis– Variation in shape and size of nucleus

• Hyperchromatism– Amount of nucleoprotein

• Nucleolar changes– Depends on NOR – Nucleolar Organising Region

• Mitotic Figures– Normal or Abnormal

• Tumour giant cells• Chromosomal abnormalities

Tumour angiogenesis and Stroma

• Tumour Angiogenesis• Formation of new vessels from pre-existing

ones• Provide nourishment to the tumour

• 2 factors• Microvascular density• Central necrosis

• Microvascular Density• New capillaries added to the tumour• Accesses the rate of growth of tumour

• Central necrosis• Fast growing tumours – poor blood supply to

the interior – undergo necrosis

Tumour Stroma

• Collagenous tissue• Scanty or Excessive

• Scanty – soft & fleshy – Sarcomas/lymphoma• Excessive – Hard & Gritty (Infiltrating DC)

• If epithelial tumour composed • Only of Epithelial cells – Medullary carcinoma• Excessive stroma – Desmoplasia/ Schirrous

Inflammatory Reaction

• Acute or Chronic• Chronic – chiefly of lymphocytes, plasma cells,

macrophages

• Granulomatous reaction in the absence of ulceration – good immunologic response

• Eg: Seminoma testis, Malignant melanoma, Medullary carcinoma of breast

2 Most Important features

• Local Invasion– Direct Spread

• Metastasis– Meta=transformation, stasis=residence– ‘spread of tumour by invasion in such a way that

discontinuous secondary tumour mass formed at the site of lodgement’

– Distant Spread

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