Neoplasia By Prof.Dr. Ahmed Mohy El Din

Intended Learning Outcomes (ILOs): Define neoplasia: Differentiate neoplastic from non neoplastic lesions. Classify benign and malignant tunours Describe the morphologic features of malignant tumors. Explain the mechanism of metastasis. Describe methods of spread of malignant tumors

Neoplasia Def :A neoplasm or a tumor is an abnormal mass of tissue the growth of which exceeds and is uncoordinated with that of the normal tissues and persists after the cessation of the stimuli which may evoke this change.

Localized Do not spread Amenable to excision Invade and destroy tissues. Spread to distant sites. Not amenable to complete surgical excision May cause death 4 I-According to Behaviour A-Benign B- Malignant

II-According to cell of origin (histogenesis) 5 Epithelial Mesenchymal Benign Malignant Benign Malignant Carcinoma Sarcoma -Papilloma -Adenoma -Fibroma -Lipoma -Chondroma

Methods of spread of Malignant tumours 1-Lymphatic spread: In general carcinomas metastasize by lymphatic route early while sarcomas favour haematogenous route. The involvement of lymph nodes by malignant cells may be Through: A.Lymphatic emboli. B.Lymphatic permeation (Regional lymph node metastasis, Sentinel LN Retrograde lymphatic spread eg Virchow’s LN & Krukenberg tumour NOT ALL REGIONAL L.N. ENLARGEMENT = METASTASIS

1-Lymphatic spread

Methods of spread of Malignant tumours 2. Haematogenous spread Blood-born metastasis is the common route for spread of sarcomas. Veins are frequently invaded by tumour cells, with a thrombus formation around tumour cells, detachment of parts of the thrombus give tumor emboli The sites where blood-borne metastasis commonly occurs are; the liver, lungs, brain and bones.

Methods of spread of Malignant tumours Organ tropism is the arrest of tumour emboli in specific organs. It is related to the expression of adhesion molecules or chemokines by the tumour cells, whose receptors are expressed on the endothelium of target organ e.g:  Cancer breast, thyroid, kidney, prostate and lung bone metastasis.  Cancer bronchus adrenal, liver and brain metastasis.  Seminoma lung metastasis.  Sarcoma lung, liver and bone metastasis.

ILOs  List important carcinogenic agents, including viruses, and discuss their proposed mechanisms of action  Define the terms; carcinogen, proto-oncogene, oncogene, tumor suppressor gene, apoptosis related genes and explain their role in carcinogenesis.  Demonstrate the molecular basis of cell growth and its regulation.  Describe the multistep carcinogenesis and give examples.  Recognize the clinical manifestations and complications of tumors.  Identify different diagnostic modalities for cancers.  Mention different Immunohitochemical tumour markers used to assess cell of origin.