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NEOPLASIA - INTRODUCTION

This article provides an overview of neoplasia, including its definition, historical background, classification based on histogenesis, and the nomenclature of benign and malignant tumors.

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NEOPLASIA - INTRODUCTION

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  1. 31/12/15 NEOPLASIA - INTRODUCTION Dr. KsheeraCariappa Assistant Professor

  2. OVERVIEW • Definition • History • Classification & Histogenesis • Nomenclature of Benign & Malignant tumours

  3. DEFINITION

  4. NEOPLASIA • The term ‘neoplasia’ means new growth (neo=new, plasia=growth); the new growth produced is called ‘neoplasm’. • Oncology (Greek oncos = tumor) is the study of tumors or neoplasms

  5. PRE-MOLECULAR ERA DEFINITION • "A neoplasm is an abnormal mass of tissue, the growth of which exceeds and is uncoordinated with that of normal tissues and persists in the same excessive manner after cessation of the stimuli which evoked the change.” - Rupert Willis

  6. MOLECULAR ERA DEFINITION • A disorder of cell growth that is triggered by a series of acquired mutations affecting a single cell and its clonal progeny.

  7. TUMOUR…? • The word tumour simply refers to a mass. (Latin ‘tumere’ = to swell) • Classically, a tumour is not necessarily a cancer. • For example, a collection of fluid would meet the definition of a tumour. • The non-neoplastic usage of tumour has almost vanished; thus, the term is now equated with neoplasm.

  8. HISTORY

  9. HISTORY • Cancer is an ancient disease. • Evidence of bone tumours has been found in prehistoric remains, and the disease is mentioned in early writings from India, Egypt, Babylonia and Greece. • Hippocrates introduced the term karkinos, from which “carcinoma” is derived - meaning crab since ‘it sticks to the part stubbornly like a crab’

  10. CLASSIFICATION & HISTOGENESIS

  11. CLASSIFICATION – currently is based on Histogenesis (i.e Cell of Origin)

  12. GENERAL OBSERVATIONS… • A Tumor is derived from cells that normally maintain a proliferative capacity. Thus, mature neurons and cardiac myocytesdo not give rise to tumours. • A tumour may express varying degrees of differentiation.

  13. GENERAL OBSERVATIONS… • The stimuli responsible for the uncontrolled proliferation may not be identifiable. • Neoplasiaarises from mutations in genes that regulate cell growth, death or DNA repair.

  14. COMPONENTS • All tumours, benign as well as malignant, have 2 basic components: • PARENCHYMA - Neoplastic cells that constitute the tumour - determines the nature and evolution of the tumour. • Reactive STROMA - Connective tissue, blood vessels, and cells of the adaptive and innate immune system – required for growth, survival and replication of tumour.

  15. COMPONENTS • The nomenclature of tumours and their biologic behavior - Parenchymal component • Growth and spread – stroma.

  16. BENIGN TUMOURS • A tumour is said to be BENIGNwhen its gross and microscopic appearances are considered relatively innocent, implying that it will : • Remain localized, • Will not spread to other sites • Is amenable to local surgical removal.

  17. BENIGN TUMOURS • As a rule, benign tumours are more differentiated than malignant ones — that is, they more closely resemble their tissue of origin. • Slow growing • Capsulated or well circumscribed.

  18. BENIGN TUMOURS ???

  19. MALIGNANT TUMOURS • MALIGNANT tumours are collectively referred to as cancers. • Malignant tumours can invade and destroy adjacent structures and spread to distant sites (metastasize) to cause death. • Most malignant tumours cause death.

  20. MALIGNANT TUMOURS • In some cases, a tumour that displays histologic characteristics of malignancy may not metastasize or be capable of killing a patient. • Basal cell carcinomas of the skin are examples of this type of tumour: they may invade subjacent structures locally but do not generally metastasize and are not life-threatening.

  21. NOMENCLATURE OF BENIGN & MALIGNANT TUMOURS

  22. BENIGN TUMOURS - NOMENCLATURE • The main rule for naming benign tumors is pretty simple: stick "-oma" on the end. • On the end of whatever tissue/cell type the tumor comes from (cartilage, smooth muscle, etc). • Have to use the latin word root. For e.g. • Chondroma (cartilage) • Leiomyoma (smooth muscle) • Fibroma (fibrous tissue)

  23. BENIGN TUMOURS - NOMENCLATURE • Lipoma (fat) • Osteoma (bone) • Hemangioma (blood vessels) • Meningioma (meninges) • Rhabdomyoma (striated muscle)

  24. BENIGN TUMOURS - NOMENCLATURE • Benign epithelial tumours are kind of a mess in terms of nomenclature. • Some are named based on their cell of origin, some on the way they look grossly, and still others on their microscopic appearance.

  25. BENIGN TUMOURS - NOMENCLATURE • An adenoma is a benign neoplasm derived from glands (adeno = glands) • "cyst-" in front of it if the adenoma has big cystic spaces in it ("cystadenoma"). • Serous cystadenoma or mucinous cystadenoma based on what the glands are secreting.

  26. BENIGN TUMOURS - NOMENCLATURE • Papilloma (an epithelial tumour that has microscopic or macroscopic finger-like projections) - Papillomas don't come from papillary tissue; the name comes from the Latin "papula" which means a small, nipple-like protuberance.

  27. BENIGN TUMOURS - NOMENCLATURE • Polyp (a neoplasm that extends above a mucosal surface) – can be benign or malignant.

  28. MALIGNANT TUMOURS - NOMENCLATURE • The main rule (add -oma to the tissue of origin) still holds. • There is an additional rule, though. • If the tumour is derived from epithelial tissues (squamous epithelium or glandular epithelium), add CARCINOMA to the end. • Carcinoma uses the Indo-European word root ”carcer”, which means barrier or enclosure.

  29. MALIGNANT TUMOURS - NOMENCLATURE • If the tumour is derived from mesenchymal tissues (basically, everything else - bone, blood vessels, muscle, fat, etc.), add SARCOMA to the end. • Sarcoma is from the greeksarx, which means flesh.

  30. MALIGNANT TUMOURS - NOMENCLATURE • MELANOMA, HEPATOMA, LYMPHOMA, SEMINOMA/DYSGERMINOMA, MESOTHELIOMA – all are named after the rule for benign tumours but are malignant. • LEUKAEMIA is the term used for cancer of hematopoietic cells.

  31. TERATOMA • Teratoma • Benign tumours that arise from germ cells and contain derivatives of different germ layers. • Principally in the gonads and occasionally in the mediastinum and may contain a variety of structures, such as skin, neurons and glial cells, thyroid, intestinal epithelium and cartilage.

  32. HAMARTOMACHORISTOMA • Localized, disordered differentiation during embryonic development results in a Hamartoma - contain varying combinations of cartilage, ducts or bronchi, connective tissue, blood vessels and lymphoid tissue. • Ectopic islands of normal tissue are called Choristoma

  33. Hamartoma of the lung - islands of hyaline cartilage and clefts lined by cuboidal epithelium embedded in a fibromuscularstroma.

  34. TAKE HOME MESSAGE • Neoplasia means new growth • It is classified as Benign & Malignant and also based on its histogenesis • Benign – oma, Malignant (carcin-oma / Sarc-oma) • Benign and malignant tumours can be distinguished from one another based on the degree of differentiation, rate of growth, local invasiveness, and distant spread. • The incidence of cancer varies with geography, age, race, and genetic background.

  35. REFERENCES • Hruban, Ralph. 'What Are tumours?'. Pathology.jhu.edu. N.p., 2015. Web. 26 Sept. 2015. • Cotran R, Kumar V, Robbins S. Pathologic basis of disease. 9th ed. Philadelphia, PA: Saunders Elsevier; 2015. Chapter 7, Neoplasia; p265-340. • Mohan H. Textbook of pathology. 6th ed. New Delhi: Jaypee Bros.; 2005. Chapter 8, Neoplasia; p192-235. • Rubin R, Strayer D, Rubin E. Rubin's pathology. 6th ed.. Philadelphia: Wolters Kluwer Health/Lippincott Williams & Wilkins; 2012. Chapter 5, Neoplasia; p157-212.

  36. THANK YOU!!!!!! HAPPY NEW YEAR

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