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NEOPLASIA Introduction

NEOPLASIA Introduction. Dr Ramadas Nayak Professor & HOD Pathology Yenepoya Medical College Mangalore. INTRODUCTION. Neoplasia =means new growth New growth formed is known as a neoplasm (Greek, neo = new + plasma = thing formed).

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NEOPLASIA Introduction

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  1. NEOPLASIAIntroduction Dr Ramadas Nayak Professor & HOD Pathology Yenepoya Medical College Mangalore

  2. INTRODUCTION • Neoplasia =means new growth • New growth formed is known as a neoplasm (Greek, neo = new + plasma = thing formed). • Term “tumor” was originally used for the swelling caused by inflammation, but it is now used synonymously with neoplasm. • Oncology(Greek, oncos= tumor) is the study of tumors or neoplasms.

  3. Willis definition • “A neoplasm is 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.”

  4. Definition • In the present era, a neoplasm can be defined as a • disorder of cell growth • which is triggered by a series of acquired mutations involving a single cell and its clonal progeny.

  5. Salient Features of Neoplasia • Origin: Neoplasms arise from cells that normally maintain a proliferative capacity. • Genetic disorder: Cancer is due to permanent genetic changes in the cell, known as mutations.

  6. Salient Features of Neoplasia • Heritable: The genetic alterations are passed down to the daughter tumor cells. • Monoclonal: • All the neoplastic cells within an individual tumor originate from a single cell/or clone of cells that has undergone genetic change. • Thus, tumors are said to be monoclonal.

  7. Salient Features of Neoplasia • Carcinogenic stimulus • The stimulus responsible for the uncontrolled cell proliferation may not be identified or is not known.

  8. Salient Features of Neoplasia • Autonomy • Excessive and unregulated proliferation of cells that do not obey the normal regulatory control. • Cell proliferation is independent of physiologic growth stimuli. • But tumors are dependent on the host for their nutrition and blood supply.

  9. Salient Features of Neoplasia • Irreversible • Neoplasm is irreversible and persist even after the inciting stimulus is withdrawn or gone.

  10. Salient Features of Neoplasia • Differentiation • Refers to the extent to which the tumor cells resemble the cell of origin. • A tumor may shows varying degrees of differentiation • ranging from relatively mature structures that mimic normal tissues (well differentiated) to cells • so primitive that the cell of origin cannot be identified (poorly differentiated).

  11. Salient Features of Neoplasia • Six Ps of neoplasm: • Purposeless • Progressive • Proliferation unregulated • Preys on host • Persists even after withdrawal of stimulus (autonomous) • Permanent genetic change in the cell.

  12. CLASSIFICATIONof Neoplasia • Tumors are classified depending on the biological behavior of a tumor as • benign and • malignant,

  13. 1. Benign tumors • They have relatively innocent microscopic and gross characteristics. • Remain localized without invasion or metastasis. • Well differentiated: Their cells closely resemble their tissue of origin. • Prognosis: It is very good, can be cured by surgical removal in most of the patients and the patient generally survives.

  14. 2. Malignant tumors • Cancer is the general term used for malignant tumors. • The term “cancer” is derived from the Latin word for crab, because similar to a crab, malignant tumors adhere to any part that they seize on, in an obstinate manner.

  15. 2. Malignant tumors • Invasion: Malignant tumors invade or infiltrate into the adjacent tissues or structures

  16. 2. Malignant tumors • Metastasis: Cancers spread to distant sites (metastasize), where the malignant cells reside, grow and again invade. • Exception: • Basal cell carcinoma of the skin, which is histologically malignant (i.e. it invades aggressively), but rarely metastasize to distant sites. • Glioma is malignant tumor of CNS. • Prognosis: Most malignant tumors cause death.

  17. Microscopic Components of Neoplasms • Tumors (both benign and malignant) consist of two basic components: • 1. Parenchyma. • 2. Stroma

  18. 1. Parenchyma • It is made up of neoplastic cells. • The nomenclature and biological behavior of tumors are based primarily on the parenchymal component of tumor.

  19. 2. Stroma • It is the supporting, non-neoplastic tissue derived from the host. • Components: Connective tissue, blood vessels and inflammatory cells (e.g. macrophages and lymphocytes).

  20. 2. Stroma • Inflammatory reaction: • Stroma may show inflammatory reaction in and around the tumors. • It may be due to ulceration and secondary infection in the tumors especially in the surface of the body.

  21. 2. Stroma • Inflammatory reaction: • Some tumors show inflammatory reaction even in the absence of ulceration. • It is due to cell mediated immunologic response of the host against the tumor as an attempt to destroy the tumor. • For example, lymphocytes in the stroma is seen in seminoma testis and medullary carcinoma of the breast.

  22. 2. Stroma • Importance of stroma • Required for growth, survival and replication of tumor (through blood supply) cells. • Tumor consistency depends on amount of stroma: • Soft and fleshy: Tumors have scanty stroma.

  23. 2. Stroma • Desmoplasia • Parenchymal tumor cells may stimulate the formation of an abundant collagenous stroma → referred to as desmoplasia. • For example, some carcinoma in female breast have stony hard consistency (or scirrhous).

  24. NOMENCLATURE OF NEOPLASMS • Benign Tumors • Generally named by attaching the suffix “oma” to the cell of origin. • 1. Mesenchymal Tumors-nomenclature

  25. NOMENCLATURE OF NEOPLASMS • 2. Epithelial Tumors • Their nomenclature is not uniform but more complex. They are classified in different ways: • a. Cells of origin • b. Microscopic pattern • c. Macroscopic architecture.

  26. NOMENCLATURE OF NEOPLASMS • Adenoma: Benign epithelial tumor arising from glandular epithelium, although they may or may not form glandular structures. • Example: Follicular adenoma of thyroid- usually shows microscopically numerous tightly packed small glands .

  27. NOMENCLATURE OF NEOPLASMS • Papilloma: Benign epithelial neoplasm that produces microscopically or macroscopically visible finger-like, exophytic or warty projections from epithelial surfaces. • Example: squamous papilloma

  28. NOMENCLATURE OF NEOPLASMS • Cystadenoma: It is a tumor forming large cystic masses. Example: Serous cystadenoma of ovary.

  29. NOMENCLATURE OF NEOPLASMS • Papillary cystadenoma: It is a tumor which consists of papillary structures that project into cystic spaces. • Example: Papillary serous cystadenoma of ovary

  30. NOMENCLATURE OF NEOPLASMS • Polyp : • It is a neoplasm that grossly produces visible projection above a mucosal surface and projects into the lumen. • It may be either benign or malignant.

  31. NOMENCLATURE OF NEOPLASMS • Polyp : • It may have a stalk (pedunculated polyp) or may be without a stalk (sessile polyp). Example: Polyp of stomach or intestine.

  32. Malignant Tumors • They are termed as carcinoma or sarcoma depending on the parenchymal cell of origin

  33. Malignant Tumors • 1. Sarcomas • They are malignant tumors arising in mesenchymal tissue. • These tumors have little connective tissue stroma and are fleshy (Greek, sar= fleshy). • Examples: Fibrosarcoma, liposarcoma, osteosarcoma, chondrosarcoma, leiomyosarcoma and rhabdomyosarcoma

  34. Malignant Tumors • 2. Carcinomas • They are malignant neoplasms arising from epithelial cell, which may be derived from any of the three germ layers

  35. Malignant Tumors • 2. Carcinomas • Undifferentiated malignant tumor • It is a malignant tumor composed of undifferentiated cells, where the cell of origin cannot be made out on light microscopic examination.

  36. Malignant Tumors • Inappropriate terminology for malignant tumor: • In certain malignant tumors, the terms suffix “oma” is inappropriately used and sounds like a benign tumor.

  37. Eponymously Named Tumors • These tumors are named after the person who first described or recognized the tumor

  38. Other Tumors • Mixed Tumors • They are derived from a single germ layer but show divergent differentiation along two lineages.

  39. Mixed Tumors • Mixed tumor of salivary gland (pleomorphic adenoma) • Derived from a single clone and • Giving rise to two components, namely • epithelial and • myoepithelial (stromal elements) cells

  40. Teratomas • They are special types of mixed tumors derived from totipotent germ cells (normally present in ovary, testis).

  41. Teratomas • Totipotent germ cells have the capacity to differentiate into any of the cell types found in the adult body. • Thus, teratoma contains recognizable mature or immature cells or tissues representative of more than one germ cell layer and sometimes all three.

  42. Teratomas • These cells or tissues are arranged in a helter-skelter fashion. • The tissue derivative from various germ cell layers may include: • 1. Ectoderm (e.g. skin, neural tissue, glia) • 2. Mesoderm (e.g. smooth muscle, cartilage, bone, fat) • 3. Endoderm (e.g. respiratory tract epithelium, gut, thyroid).

  43. Hamartomas • It is a disorganized mass of benign-appearing cells, indigenous to the particular site. • Example: Pulmonary chondroid hamartoma consists of islands of disorganized, but histologically normal cartilage, bronchi and vessels

  44. Choristoma • It is an ectopic island of normal tissue—heterotopic rest (normal tissue in an abnormal site) and is a congenital anomaly. • Example: Presence of small nodular mass of normally organized pancreatic tissue in the submucosa of the stomach, duodenum, or small intestine.

  45. Embryonal Tumors (Blastomas) • They are the type of tumor developed only in children (usually below 5 years of age) • Microscopically resemble embryonic tissue of the organ in which they arise

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