Path 822: Experimental Cancer Diagnostics & Therapeutics: PATHOLOGY OF TUMOURS Sandip SenGupta, M.D. Professor of Pathology September 2005

Objectives Understand the nomenclature, similarities and differences between benign and malignant neoplasms Discuss current tools for pathological diagnosis Understand how pathological information about tumours affects clinical management (through TNM staging)

Reading Material

Definitions Neoplasia: “ new growth ” Tumour: a swelling Oncology: the study of tumours or neoplasms Cancer: common term for all malignant tumours 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 ”.

Biology of Tumour Growth: Benign & Malignant Neoplasms Differentiation and Anaplasia 1.Pleomorphism 2.Abnormal nuclear morphology 3.Mitoses 4.Loss of polarity 5.Other changes – e.g. tumour giant cells Rate of Growth 1.Doubling time of tumour cells 2.Fraction of tumour cells in replicative pool Local Invasion Metastasis –Benign tumours do not metastasize!

Nomenclature Epithelial tumours –Stratified squamous –Basal cells of skin or adnexa –Glands or ducts –Respiratory passages –Neuroectoderm –Renal epithelium –Liver cells –Urinary tract –Placental (trophoblast) –Testicular (germ cells) Mesenchymal tumours –Connective tissue and derivatives – eg. Fibroma, lipoma –Endothelial and related tissues – eg. hemangioma –Blood cells and related tissues – eg. Leukemias –Muscle – smooth or striated

Benign Tumours – Gross Pathology Thyroid - adenoma Colon - polyps Uterus – “fibroid”Ovary – “dermoid cyst”

Malignant Tumours – Gross Pathology Colon - adenocarcinoma Long bone - osteosarcoma Lung – bronchogenic carcinoma Uterus – cancer of the cervix

Pathways of Spread of Malignant Tumours Direct seeding of body cavities or surfaces Lymphatic spread Hematogenous spread