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NEOPLASIA Presented by Dr Abudu Emmanuel Kunle (MBBS, M.Sc, FMCPath) Senior Lecturer and Consultant Histopathologist University of Uyo Teaching Hospital,Uyo, Akwa- Ibom State, Nigeria. Neoplasia means the process of new growth whilst Neoplasm means a new growth. Sometimes, the parenchyma cells stimulate the formation of an abundant collagenous stroma, referred to as desmoplasia. Some tumours e.g. some cancers of breast are stony hard or scirrhous. Sarcomas have little connective tissue stroma and so are fleshy. Pseudo tumours: i) An ectopic rest of normal tissue is sometimes called a choristoma e.g a rest of adrenal cells under the kidney capsule or a pancreatic nodular rest in the mucosa of the small intestine may mimic neoplasm.…show more content…
Cancer stem cells and cancer cell lineages: cancer stem cells are cells within the tumour that have the capacity to initiate and sustain the tumour. 3) Local invasion: Benign tumours are usually encapsulated except haemangioma while malignant tumours can locally invade and destroy the adjacent tissues. Next to the development of metastases, invasiveness is the most reliable feature that differentiate malignant from benign Tumours. Carcinoma in situ is best seen in tumour of skin, breast, cervix, vagina, in which display the cytologic features of malignancy without invasion of the basement membrane. a) Biology of tumour growth: Benign and malignant neoplasms contd 4) Metastasis: metastases are tumour implants discontinuous with the primary tumour. All cancers can metastasize except those of glial cells in CNS (Gliomas), and basal cell carcinoma of the skin but they are locally invasive. Pathways of spread: i) Seeding of body cavities and surfaces: esp. carcinoma of ovaries and sometimes mucus-secreting appendiceal carcinoma fill the peritoneal cavity with a gelatinous neoplastic mass referred to as pseudomyxoma peritonei. ii) Lymphatic spread: is the most common pathway for the initial dissemination of carcinomas, and sarcomas as well. The pattern of lymph node involvement follows the routes of lymphatic drainage. A Sentinel Lymph Node is defined as the first node in a regional lymphatic basin that receives
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