Neoplasia I PDF - Benha National University

Neoplasia I  Learning Objectives Explain the different points related to neoplasia regarding its definition, aetiology, its classifications to benign and malignant epithelial tumours, benign and malignant connective tissue tumours,. Contrast benign from malignant tumors. Und...

Neoplasia I  Learning Objectives Explain the different points related to neoplasia regarding its definition, aetiology, its classifications to benign and malignant epithelial tumours, benign and malignant connective tissue tumours,. Contrast benign from malignant tumors. Understand clinical effects of neoplasms and know the diagnostic modalities for neoplasm Characteristics of benign and malignant tumors. Diff between benign and malignant tumors (as table) Metastasis: pathways of spread of tumor (very important)  General terms used Neoplasia means "new growth Neoplasm mass of tissue, the growth of which EXCEEDS and is UNCOORDINATED with that of the normal tissues and PERSISTS in the same excessive manner AFTER CESSATION of the stimulus which produce the change.“ Benign neoplasm = Limited new growth without invasion or spread Malignant neoplasm = invasive growth that also spreads Cancer is a general term for all malignant growths of whatever type Tumor may be used instead of neoplasm, but the term is not accurate Oncology : study of cancer in all its aspects  Concepts of cell growth Proliferation is cell division, replicating body cells when old cells die (skin & blood cells) or additional cells are needed Growth, repair & healing). Differentiation is specialization whereby new cells acquire the structure and function of the cells they replace.  Classification of Tumors Behavior of tumor : Benign or Malignant or Locally malignant tumors. Cell of origin: Epithelial (neoplasia of lining tissues), Mesenchymal (neoplasia of connective tissue derivatives), Germ cell (neoplasia of undifferentiated stem cells ,sperm, ovarian egg etc). Appearance of the tumor: Solid/cystic Degree of differentiation (well, moderate, poorly)  Structure of neoplasms : Neoplasms are composed of: 1) Neoplastic parenchymal (transformed) cells: The majority of tumors arise from single transformed cell, i.e. monoclonal. decides behavior & Pathologic consequences 2) Supporting stroma and blood vessels: Degree & type of stromal cells may contribute to the appearance of tumors If there is stromal proliferation → hardness of the tumor → Scirrhous tumor → Desmoplasia e.g. carcinoma of breast, pancreas…..etc Soft & fleshy neoplasm→ Scant stroma Greater numbers of vessels (angiogenesis). Scirrhous Carcinoma of breast Serous cystadenoma of ovary  Nomenclature Neoplasia- Benign Epithelial Mesenchymal Not easy Easy =Cell origin + oma Adenoma → benign epithelial tumor derived from or present with glandular pattern Chondro + Oma = Chondroma {Cartilag Papilloma → finger-like or warty projections with a Fibro + Oma = Fibroma {Fibroblast} connective tissue core from the epithelial surfaces (MC - Lipo + Oma = Lipoma skin) Polyp → fist-like projection from mucosal epithelial {Fat/ lipocyte / adipocyte} surfaces from the mucosal surface of a hollow organ (MC - colon) Cystadenomas: forms large cystic mass (ovaries) Papillary cystadenoma: papillary patterns that protrude into the cystic spaces (ovaries)  Nomenclature Neoplasia- Malignant Epithelial Mesenchymal CARCINOMA (any germ layer) SARCOMA Adenocarcinoma→ glandular growth pattern Greek = “fleshy” ( little stroma) Squamous cell carcinoma→ squamous cell differentiation Chondro + sarcoma = Chondrosarcoma specify organ of origin →Renal cell adenocarcinoma, {Cartilage} Bronchogenic Fibro + sarcoma = Fibrosarcoma Undifferentiated/ poorly differentiated →Can’t {Fibroblast} determine tissue of origin Mixed tumors →Pleomorphic adenoma Lipo + sarcoma = Liposarcoma Divergent differentiation of a single germ line of {Fat/ lipocyte / adipocyte} parenchymal cells (salivary gland) Rhabdomyo +sarcoma = Teratoma → From Totipotential cells (gonads), more Rhabdomyosarcoma than one germ layer { Dermoid cyst → ovary} {striated muscle} Benign -Epithelial B A Adenoma of the intentstine  Benign Mesenchymal Epithelial Leiomyoma Adenoma of the thyroid  Mixed Tumors : Tumors derived from a single germ cell layer that differentiates into more than one cell type. e.g. mixed tumor of salivary gland, Fibroadenoma of breast OR : Teratomas – made of a variety of parenchymal cell types that derive from more than one germ cell layer formed by totipotent cells that are able to form ectoderm, endoderm & mesoderm  TERATOMA : May be benign or malignant Contain skin ,sebaceous & mucus glands, hair, cartilage, bone, respiratory epithelium, glial tissue…..etc. Usual location is ovary or testes  Tumors of primitive fetal origin Blastoma : from immature tissue May arise in kidney, liver, retina…etc e.g. nephroblastoma, hepatoblastoma, and Retinoblastoma The great majority of these tumors are malignant & occur in infants & children  Some tumors have names that do not conform with general rules Malignant neoplasia with benign suffixes Melanomas arise from nevus cells Seminomas arise from testicular germ cells Lymphomas arise from lymph nodes Mesothelioma Some tumors are named eponymously e.g. Hodgkins disease, Wilm’s tumor….etc  Some ‘tumors’ are NOT true neoplasms Hamartoma : Choristoma : Is an overgrowth of mature tissues that is a mass of normal tissue in an normally occur in an area of the body, but abnormal location; Ectopic with disorganization (abnormal mixing of normal components of the organ ,either in tissue the form of change in quantity or e.g. Meckle’s Diverticulum, arrangement of tissue elements) and often with one element predominating Salivary tissue in LN Tumor like malformation in e.g. Lung Both are present at birth & do Hamartoma. not become malignant.  FLASHCARD Which of the following is correct regarding classification and nomenclature of neoplasms? a) Histogenesis of a tumor refers to its behavior. b) A sarcoma is a benign tumor of glandular epithelium. c) A carcinoma is an epithelial malignancy d) Leiomyosarcoma is a malignant tumor of skeletal muscle  FLASHCARD Which of the following is correct regarding classification and nomenclature of neoplasms? a) Histogenesis of a tumor refers to its behavior. b) A sarcoma is a benign tumor of glandular epithelium. c) A carcinoma is an epithelial malignancy d) Leiomyosarcoma is a malignant tumor of skeletal muscle  How do benign & malignant tumors differ? Differentiation & anaplasia Rate of growth Presence of capsule Local invasion Distant metastases  1- Differentiation: - This indicates the degree of resemblance of the tumor cell to its cell of origin, functionally & morphologically. e.g – Cells of a lipoma may look exactly like normal fat cells. LIPOMA LIPOSARCOMA  Features of differentiation include Epithelial cells : - formation of glands - formation of keratin - formation of secretion…etc Connective tissue cells : - formation of osteoid - presence of lipoblasts - Striations in tumors of skeletal muscle….etc Well formed glandular No acini ! SIGNET CELLS architecture - DYSPLASIA is an abnormal growth which may precede malignancy with gradual loss of differentiation Complete loss of differentiation = ANAPLASIA  Cytological Features of Dysplasia Increased nuclear size ,  N/C ratio Variation in nuclear & cell size : PLEOMORPHISM Loss of differentiating features Increased nuclear DNA content: HYPERCHROMATISM Nucleoli :Prominent, sometimes multiple Mitotic figures : Increased Abnormal mitoses: may be present Loss of polarity : in an epithelial surface Severe Dysplasia/ Anaplasia  Intraepithelial Neoplasia Dysplasia involving an epithelial surface Low grade & High grade High grade dysplasia ,limited by epithelial basement membrane = CARCINOMA IN SITU Full-thickness dysplasia extending from the basement membrane to the surface of the epithelium. Applicable only to epithelial neoplasms. If the entire lesion is no more advanced than CIS, then the risk of metastasis is zero. This is because there are no blood vessels or lymphatics within the epithelium above the basement membrane. Intraepithelial Neoplasia  NOTE : Not all dysplasias progress to higher grade or carcinoma in situ. Not all carcinoma in situ progress to invasive CA Some cases of dysplasia can regress  2- Rate of growth Rate of growth usually correlates with level of differentiation May be rapid in some benign tumors Some tumors may shrink in size Some malignant tumors may outgrow their blood supply Some tumor growths are semi controlled :HORMONE DEPENDENCE This is through presence of receptors on surface Breast CA Thyroid CA Prostatic CA  3- Local invasion & Encapsulation Benign tumors frequently have a capsule Malignant tumors progressively invade & destroy surrounding tissue e.g. Breast cancer infiltrating skin Basal cell carcinoma face infiltrating nerve *Second most important feature distinguishing malignant tumors  4- Metastasis Spread of malignant tumors to distant sites not contagious with the main tumor Most important in diagnosing malignancy All tumors can potentially metastasize except LOCALLY MALIGNANT TUMOR as BASAL CELL CARCINOMA Metastasis is often proportionate to the size and differentiation of the primary tumor  FLASHCARD All are nuclear features of malignancy Except: a) Presence of mitotic figures. b) Hyperchromatism. c) Decreased nuclear cytoplasmic ratio. d) Chromatin clumping e) Prominent nucleolus.  FLASHCARD All are nuclear features of malignancy Except: a) Presence of mitotic figures. b) Hyperchromatism. c) Decreased nuclear cytoplasmic ratio. d) Chromatin clumping e) Prominent nucleolus.