UTHSC Fall 2022 D2 Par 3 Pathology

UTHSC Fall 2022 D2 Par 3 Pathology Neoplasia New growth Neoplasm An abnormal 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 stimuli which evoked the change Tumor and neoplasm are (antonym/synonym) synonym hyperplasia increase in number of cells Tumor originally applied to the swelling caused by inflammation, now equated with neoplasm. Oncology study of tumors or neoplasms Neoplasms origin • Epithelial • Mesenchymal Neoplasms Biologic Behavior • Benign • Malignant when is a tumor said to be benign? when its gross and microscopic appearances are considered relatively innocent, implying that it will remain localized, will not spread to other sites, and is amenable to local surgical removal how are benign tumors designated in vocabulary? by attaching the suffix -oma to the name of the cell type from which the tumor originates what do epithelial neoplasms arise from? surface linings or glands Adenoma a benign tumor of glands Polyp a mass arising on an epithelial surface, not necessarily a neoplasm, such as nasal polyp Papilloma a polyp with finger-like projections due to a benign neoplastic epithelial hyperplasia Benign Mesenchymal Neoplasms Nomenclature Suffix "-oma" - Generally named for the neoplastic cell type - Examples: lipoma, fibroma, leiomyoma - Exceptions: Malignant: Melanoma, lymphoma, multiple myeloma, mesothelioma, seminoma - Inflammatory (benign): Granuloma, hematoma T/F The following terms have specific definition and not all considered as a benign neoplasm: - Teratoma - Hamartoma - Choristoma True Teratoma A tumor containing recognizable mature or immature cell or tissues belonging to more than one germ cell layer (and sometimes all three) - Originates from totipotential germ cells what germ layer does a teratoma originate from? totipotential germ cells Hamartoma A focal malformation, composed of excessive and disorganized tissue elements normally found at that site Choristoma - A heterotopic rest of cells or tissue Examples: a small nodule of well-developed and normally organized pancreatic tissue found in the stomach Malignant Neoplasms - Referred to as cancers - Malignant tumors can invade and destroy adjacent structures and spread to distant sites (metastasize) to cause death Carcinoma • Cancer arising from epithelial cells • Squamous cell carcinoma, basal cell carcinoma Sarcoma • Cancer arising from connective tissue elements • Osteosarcoma, fibrosarcoma characteristics of a benign tumor - intact skin surface - expansile growth - capsule - homogenous cut surface characteristics of a malignant tumor? - ulceration of skin - invasive growth - inhomogeneous cut surface - necrosis - hemorrhage - vessel invasion - lymphatic invasion what are the distinguishing features between benign and malignant tumors? - Cell characteristics - Rate of growth - Local invasion - Metastasis tumor with cells that closely resemble normal cells designate a (benign/malignant) tumor benign a tumor with cells that are irregular in shape and size and do not completely resemble normal cells designate a (benign/malignant) tumor malignant Differentiation The extent to which neoplastic cells resemble the normal cells in the tissue of origin, morphologically and functionally Atypia Structural abnormality in a cell Anaplasia lack of differentiation, a hallmark of malignancy (Benign/Malignant) tumors, usually well-differentiated Benign (Benign/Malignant) tumors, showing cellular atypia and wider spectrum of differentiation Malignant what is the spectrum of differentiation from least to most differentiated? - Well differentiated - Moderately differentiated - Poorly differentiated - Undifferentiated (Anaplastic) Benign tumor characteristics Intact skin surface Expansile growth Capsule Homogenous Cut surface malignant tumor characteristics Invasive growth Ulceration of skin Lymphatic invasion Inhomogenous cut surface Necrosis Hemorrhage Vessel invasion Histopathologically, malignant tumors demonstrate cellular atypia Features of Cellular Atypia - Pleomorphism (variation in cell size and shape, tumor giant cells) - Increased nucleus/cytoplasm ratio - Abnormal nuclear morphology; nuclear hyperchromatism (darker in color) - Prominent nucleoli - Mitoses (increased number and presence of atypical mitotic figures) - Loss of polarity Dysplasia - Literally means "disordered growth" - Principally in epithelia - Constellation of changes including loss of uniformity of the individual cells and loss of their architectural orientation Metaplasia One differentiated cell type (epithelial or mesenchymal) is replaced by another cell type. The most common: columnar to squamous what is the most common metaplasia? columnar to squamous T/F Epithelial metaplasia , double-edged sword and, in most circumstances persistent epithelial metaplasia (columnar to squamous, seen in the lung), may initiate malignant transformation (dysplastic changes). True Hyperkeratosis Thickening of the skin caused by a mass of keratinocytes Hyperplasia increase in number of cells dysplasia is a precursor of a (benign/malignant) process malignant Dysplasia is a "______________" lesion premalignant Mild Epithelial Dysplasia Cellular atypia seen in the basal and parabasal cell layers of the epithelium Moderate Epithelial Dysplasia Cellular atypia seen from the basal layer to the midportion of the spinous layer Severe Epithelial Dysplasia Cellular atypia seen from the basal layer to a level above the midpoint of the epithelium Carcinoma in Situ Cellular atypia seen in the entire thickness of the epithelium Invasive Carcinoma Cells have invaded the basement membrane using collagenases and hydrolases (metalloproteinases). Cell to cell contact is lost due to inactivation of E-cadherin. Local Invasion of benign tumors • Grow as cohesive expansile masses, remained localized to their site of origin • Lack of capacity to infiltrate, invade, or metastasize to distant sites Local Invasion of Malignant tumors Infiltration, invasion, and destruction of the surrounding tissue Metastasis - The spread of a tumor to sites that are physically discontinuous with the primary tumor (distant sites) - As an unequivocal hallmark of a malignant tumor - Benign neoplasms do not metastasize. - Exceptions: glioma (malignant tumor in the CNS) and basal cell carcinoma (skin) rarely metastasize what is the unequivocal hallmark of a malignant tumor? Metastasis T/F benign neoplasms can metastasize False Pathways of spread of cancer - Direct seeding of body cavities or surfaces - Lymphatic spread - Hematogenous spread Seeding of Body Cavities and Surfaces - Malignant neoplasm penetrates into a natural "open field" lacking physical barriers - Most often involved is the peritoneal cavity - Any other cavity such as pleural, pericardial, subarachnoid, and joint spaces may be affected What is the most common pathway for the initial dissemination of carcinomas? Lymphatic Spread what are some examples of Lymphatic spread of cancer? - Axillary lymph nodes involvement in breast carcinomas - Cervical lymph nodes involvement in oral squamous cell carcinomas Hematogenous Spread - Typical for spread of sarcomas - Arteries, less readily penetrated than veins because of thicker walls - Liver and the lungs, most frequently involved Long Summary of Characteristics of Benign and Malignant Neoplasms - Benign and malignant tumors can be distinguished from one another based on the degree of differentiation, rate of growth, local invasiveness, and distant spread. - Benign tumors resemble the tissue of origin and are well differentiated; malignant tumors are less well differentiated or completely undifferentiated (anaplastic). - Benign tumors are more likely to retain functions of their cells of origin, whereas malignant tumors sometimes acquire unexpected functions due to derangements in differentiation. - Benign tumors are slow growing, while malignant tumors generally grow faster. - Benign tumors are circumscribed and have a capsule; malignant tumors are poorly circumscribed and invade surrounding normal tissues. - Benign tumors remain localized at the site of origin, whereas malignant tumors metastasize to distant sites Why do we need to do epidemiologic Studies for cancer? - Using epidemiologic studies, some information about environmental, racial, and cultural influences to the occurrence of specific neoplasms are collected. - Major insights into the causes of cancer may be obtained Epidemiology of Cancer - The second leading cause of death in the United States - About 25% of males and 20% of females in the U.S die from cancer. - Cancers of the lung, breast, prostate, and colon/rectum account for over 50% of cancer diagnoses and deaths. - Over the last 50 years incidence rates have stabilized, and death rates have decreased what is the second leading cause of death in the US? Cancer What is the leading cause of death in the US?