Neoplasia-1 PDF

Neoplasia-1 Dr.Gehan Abdelmenam  Intended Learning Objectives Recall definition,general features,components and classification of neoplasia. Describe gross&microscopic morphology,behavior of benign tumors. Describe gross&microscopic morphology,behavior ,nomenclature of maligna...

Neoplasia-1 Dr.Gehan Abdelmenam  Intended Learning Objectives Recall definition,general features,components and classification of neoplasia. Describe gross&microscopic morphology,behavior of benign tumors. Describe gross&microscopic morphology,behavior ,nomenclature of malignant tumors.  Neoplasia * Definition: It is a new growth formed by uncontrolled, unlimited multiplication of abnormal cells. * General features of neoplasia: Tumor arises as a result of mutation (genetic damage) acquired either by environmental factors or inherited in germ cell line. The tumor is formed by clonal proliferation of a single precursor cell  Any cell can give rise to tumor, but more frequent in labile cells, followed by stable cells, and then least in the permanent cells. Neoplasms (tumors) have two components: 1. Parenchyma: Made up of proliferating neoplastic cells Determines the biologic behavior of the tumor e.g. benign or malignant. 2. Stroma (Supporting tissue): Made up of non-neoplastic connective tissue & blood vessels.  Classification of Neoplasms Epithelial tumors Mesenchymal tumors Benign Malignant Benign Malignant Benign tumors General characters * Gross picture: – Size: Usually small in size – Shape: a. Tumors arising from surface epithelium: papilloma (finger-like projection). e.g. squamous cell papilloma of skin. b. Tumors arising from inside an organ: rounded mass surrounded by a fibrous capsule. e.g. thyroid adenoma. – Capsule: usually capsulated – Hemorrhage and necrosis: usually absent papilloma * Microscopic picture: Differentiation: The tumor cells are closely similar to the parent tissue in the pattern of arrangement (well differentiated). Cellular features: the tumor cells resemble the parent tissue cells. Stroma: is usually well formed with Thyroid adenoma * Behavior of benign tumors: – Rate of growth: usually slow – Mode of growth: by expansion – Localization: usually localized – Effects on the host: usually do not destroy the surrounding structures and do not kill the patient (except in certain sites as in brain) – Recurrence: usually not recurrent if well excised. – Metastasis (spread away): Do not metastasize – Malignant change: may occur * Nomenclature of Benign tumors: * Benign epithelial tumors: Papilloma: benign tumor arising from protective surface epithelium e.g. squamous cell papilloma. Adenoma: benign tumor arising from secretory epithelium e.g. thyroid adenoma. * Benign mesenchymal tumors: Fibroblast: fibroma. Fat cell: lipoma. Chondroblast: chondroma. Osteoblast: osteoma. Smooth muscle: leiomyoma. Striated muscle: rhabdomyoma. Lipoma Chondroma Malignant tumors General characters * Gross picture: – Size: Usually reach large size – Shape: a. Tumors arising from surface epithelium. E.g. cancer skin, colon, stomach…. 1. Polypoid (fungating). 2. Ulcerative: 3. Infiltrative. b. Tumors arising from an organ.e.g. liver: form a mass, non-capsulated, with infiltrative borders. - Capsule: non-capsulated – Hemorrhage and necrosis: common  Fungating Ulcerative * Microscopic pathology: – Differentiation: The cells show loss of differentiation – Cellular features: the cells show atypia(dysplasia) i.e. pleomorphism, hyperchromatism, increase N/C ratio , abnormal mitosis and prominent nucleoli.  Cellular features of atypia in malignant cells Abnormal mitosis Hyperchromat ism  Cellular features of atypia in malignant cells ominent neucleoli * Behavior of malignant tumors: – Rate of growth: usually rapid – Mode of growth: by infiltration – Localization: usually not localized – Effects on the host: can kill the patient wherever present – Recurrence: may recur – Metastasis: may occur * Nomenclature of Malignant tumors: Malignant epithelial tumors are called CARCINOMA: – Squamous cell carcinoma. – Renal cell carcinoma. – Hepatocellular carcinoma. - Malignant mesenchymal tumors are called SARCOMA: Fibroblast: Fibrosarcoma Fat cell: Liposarcoma. Chondroblast : Chondrosarcoma. Osteoblast : Osteosarcoma Smooth muscle: Leiomyosarcoma. Striated muscle: Rhabdomyosarcoma. Some Exceptions in Nomenclature of Malignant tumors These are malignant tumors, but end with suffix “oma”:  Melanoma ( skin )  Adamantinoma (bone specially tibia)  Hepatoma( hepatocellular carcinoma)  Lymphoma ( lymphoid tissue )  Seminoma ( testis )  REFERENCES Robbins and Cotran Pathologic Basis of Disease, 9th edition, 2014 ( Kumar, Abbas, Aster) Robbins Basic Pathology 10th edition, 2017 ( Kumar, Abbas, Aster)