Neoplasia IIntroduction

Husni Maqboul, M.D.

Terminology

• Tumor : Pathologic disturbance of growth, characterized by excessive and unnecessary proliferation of cells

• Galen (131 - 201 AD )

– Swelling according to nature ( pregnancy )

– Swelling exceeding nature ( Callus )

– Swelling contrary to nature

Terminology

• Hamartoma : Excessive but focal overgrowth of cells and tissues native to the organ in which it occurs. Cellular elements are mature, but do not produce normal architecture

– Hamartroma of lung

– Angiomas

– Pigmented nevi

Terminology

• Choristoma (Heterotopia) : Normal cells or tissues, that are present in abnormal locations

– Pancreatic cells in the wall of stomach or intestine

– Nests of adrenal cells in kidney , lung or ovaries

Terminology

• Neoplasms : Persistent , abnormal and relatively autonomous proliferation of cells occurring as a result of permanent cellular defect that is passed to the progeny. Usually develops due to a factor(s) , but once developed , becomes independent of them.

Types of neoplasms

• Neoplasms– Parenchyma made up of neoplastic cells– Supporting host derived stroma

• Benign: localized and amenable to surgical removal; patient usually survives

• Malignant: invasive tumor capable of destroying structures and spread to distant sites (metastasis); may result in early death of the patient

Examples of benign tumors

• Epithelial– Adenoma: benign glandular tumor– Papilloma : benign surface epithelial tumors– Polyp : benign tumor projecting over mucosal

surface– Cystadenoma : benign epithelial tumor forming

hollow cystic mass

Examples of benign tumors• Mesenchymal

– Chondroma: benign cartilaginous tumor– Leiomyoma: benign smooth muscle tumor– lipoma: benign tumor of fat– Fibroma: benign tumor of fibrous tissue

• Mixed– Benign Mixed Tumor –divergent differentiation of

stem cell (pleomorphic adenoma)– Fibroadenoma – neoplastic fibrous component

• More than one germ cell layer– Benign teratoma – mature components

leiomyomas

adenoma

Examples of malignant tumors

• Sarcoma (mesenchymal derivation: fibrosarcoma, chondrosarcoma)

• Carcinoma (epithelial derivation: adenocarcinoma, squamous cell carcinoma)– Squamous– Adeno– Transitional

• Lymphoma/leukemia

adenocarcinoma

carcinoma

• The terms “benign” and “malignant” describe the biologic behavior of a tumor

• The biologic behavior is characterized by degree of differentiation of the tumor , rate of growth (and rate of cell death) , infiltration of surrounding tissue, and dissemination to distant sites

Differentiation

• Well-differentiated tumors contain cells that resemble the normal cells of origin

• Poorly-differentiated or undifferentiated tumors contain cells that do not resemble their normal counterparts (ancillary studies may be needed to determine the cell of origin)

well-differentiated

poorly-differentiated

• Benign tumors are composed of well-differentiated cells.

• Malignant tumors are characterized by a wide range of cellular differentiation.

• Anaplasia (cellular pleomorphism, hyperchromatic nuclei, high N:C ratio, giant cells, bizarre nuclei) is a feature of malignant tumors.

Differentiation

anaplasia

Dysplasia

• denotes a loss of architectural organization and a loss of cell uniformity in epithelium

• pleomorphism and mitoses are more prominent than in the normal

• usually graded: mild, moderate, severe, and carcinoma-in-situ

• mild to moderate dysplasia is potentially reversible

normal epithelium

dysplasia

Dysplasia

• Dysplasia is a non-neoplastic proliferation.

• Dysplasia may or may not progress to cancer.

Rate of growth

• In general, benign and well-differentiated malignant tumors have a slower rate of growth than moderately-differentiated and poorly-differentiated malignant tumors.

• There are exceptions. Blood supply, site, and hormonal stimulation are factors that can affect the growth rate of tumors.

Invasion

• Benign tumors usually grow by slow expansion.

• Malignant tumors usually infiltrate and may destroy surrounding tissue (cell surface and the extracellular matrix play an important role).

Functional characteristics

• Benign tumors are more likely to function

• Epithelial tumors can produce mucin

• Hormonal production can be unregulated

• Inappropriate production of hormones by different type of cells

• Abnormal receptor and antigenic expression

Metastasis

• indicates malignancy

• a discontinuous spread of the tumor

• Methods of metastasis include: (1)seeding of body cavities, (2) lymphatic spread, and (3) hematogenous spread.

metastatic ovarian carcinoma

MRI: metastatic adenocarcinoma

metastatic adenocarcinoma

Grading and staging

• Grading is based on the microscopic features of the cells which compose a tumor and is specific for the tumor type.

• Staging is based on clinical, radiological, and surgical criteria, such as, tumor size, involvement of regional lymph nodes, and presence of metastases. Staging usually has more prognostic value.

Morbidity and mortality

• metastases

• rupture into major vessels

• compression of vital organs

• organ failure

• infection

meningioma

basal cell carcinoma

melanoma

Diagnostic procedures

• FNA (fine needle aspiration)

• Cytological smears

• Biopsy

• Frozen sections

• Biochemical assays

• Molecular diagnosis

• Flow cytometry

cytology smear: adenocarcinoma

Pap smear with dysplasia

frozen section

staining a frozen section

Ancillary studies

• Immunohistochemistry

• Cytogenetics

• Flow cytometry

• Electron microscopy

cytokeratin stain on a carcinoma

AFP stain on a yolk sac tumor

EM: neurosecretory granules

EM: microvilli, tight junction in an adenocarcinoma

Biochemical assays

• Tumor markers: sometimes diagnostic or prognostic

• Can be helpful in monitoring effectiveness of therapy or in detecting relapses/recurrences

Summary

• Neoplasia- an abnormal mass of tissue which has lost its responsiveness to growth controls

• Benign neoplasms tend to be slow-growing, well-differentiated tumors which lack the ability to metastasize

• Benign neoplasms, in general, remain localized and are amenable to surgery

Summary

• Malignant neoplasms tend to be fast-growing lesions which invade normal structures

• Malignant neoplasms vary in the degree of differentiation and some show anaplasia

• Malignant neoplasms are capable of metastasis

Summary

• The prognosis of a patient with any type of neoplasm depends on a number of factors including: the rate of growth of the tumor, the size of the tumor, the tumor site, the cell type and degree of differentiation, the presence of metastasis, responsiveness to therapy, and the general health of the patient.