Neoplasia .pdf........................................................

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1. NEOPLASIA Dr. Smritee Sharma Adhikari

2. §Neoplasia: new growth
§Neoplasm: collection of cells and stroma composing new growths
§Oncology: Greek oncos= tumor
ü Study of tumors or neoplasms
§Definition by Willis: “an abnormal mass of tissue, the growth of which
exceeds and is uncoordinated with that of the surrounding normal tissues, and
persists in the same excessive manner after cessation of the stimuli which
evoked the change”
§Modern definition: “genetic disorder of cell growth that is triggered by
acquired or less commonly inherited mutations affecting a single cell and its
clonal progeny”

3. TWO COMPONENTS OF TUMOR
1.Neoplastic cells that constitute the tumor parenchyma
2.Reactive stroma made up of connective tissue, blood vessels and
cells of adaptive and innate immune system
§ Classification and biological behavior based on parenchymal
component
§ Growth and spread dependent on stroma

4. NOMENCLATURE

5. BENIGN TUMORS
§remain localized at their site of origin and generally amenable to
surgical removal
§Mesenchymal cells: suffix “–oma”
ü Fibroblast like cells: Fibroma
ü Cartilaginous tumor: Chondroma
§Epithelial cells: complex; based on their cell of origin/ microscopic
appearance/ macroscopic architecture
ü Derived from glandular tissue: Adenoma
ü Finger like or warty projections from epithelial surfaces:
Papillomas

6. üLarge cystic masses, as in ovary: Cystadenomas
üPapillary projections that protrude into cystic spaces: Papillary
cystadenoma
üGrossly visible projections above mucosal surface: Polyp

7. MALIGNANT TUMORS
§Invade and destroy adjacent structures and spread to distant sites
(metastasize)
§Cancer: Latin word for CRAB
§Solid mesenchymal tissue: Sarcoma (Greek sarc= fleshy)
§Blood forming cells: Leukemia (white blood) or Lymphoma (lymphocytes
or their precursors)
§Epithelial cell origin: Carcinoma
§Squamous cell carcinoma: tumor cells resemble stratified squamous
epithelium
§Adenocarcinoma: in glandular pattern

8. F
Fig: Normal glands

9. Fig: Normal liver
Fig: Normal lungs histology

12. MIXED TUMORS
§Pleomorphic adenoma of salivary gland: contains epithelial component
scattered within a myxoid stroma that may contain islands of cartilage
or bone
§Teratoma: contains recognizable mature or immature cells or tissues of
more than one germ cell layer
§Misnomers:
§Lymphoma: malignant tumor of lymphoid cells
§Melanoma: Malignant tumor of melanocytes
§Mesothelioma: Malignant tumor of mesothelial tissue (eg. Pleura)
§Seminoma: Malignant tumor of testis

14. Fig: Normal ovary

15. ABBERATIONS
§Hamartoma: disorganized masses composed of cells indigenous to the
involved tissue
§Choristoma: heterotopic (misplaced) rest of cells
üEg. a small nodule of well developed, normally organized
pancreatic tissue found in the submucosa of stomach or small
intestine.

16. FEW TERMS
§Differentiation: extent to which neoplastic parenchymal cells resemble
the corresponding normal parenchymal cells, both morphologically and
functionally
§Anaplasia: Lack of differentiation
Fig: Anaplastic tumor showing cellular and nuclear
variation in size and shape.
The prominent cell in the center field has an
abnormal tripolar spindle shape

17. Fig: Normal skin histology

19. Fig: Normal myometrium

20. §Pleomorphism: variation in cell size and shape
§Abnormal nuclear morphology:
üN:C ratio approach 1:1 (normal 1:4 to 1:6);
ünuclear shape variable, irregular;
üchromatin: coarsely clumped and distributed along nuclear membrane/
hyperchromatic;
ülarge nucleoli
§Mitoses: Reflects high rate of proliferations; rapid turnover
üDoes not equate with malignancy
üMalignancy: atypical, bizarre mitotic figures
§Loss of polarity: orientation of anaplastic cells with respect to each other or
to supporting structures like basement membranes is markedly disturbed

21. §Metaplasia:
üReplacement of one type of cell with another type
üIn association with tissue damage, repair and regeneration
üReplacing cell type is better suited to some alteration in the local
environment
üEg. Barrett esophagus: Gastroesophageal reflux damages
squamous epithelium of esophagus replacement by glandular
(gastric or intestinal) epithelium  better suited to an acidic
environment
üMetaplastic epithelium prone to malignant transformation

22. §Dysplasia: “disordered growth”
üConsiderable pleomorphism
üLarge hyperchromatic nuclei
üHigh N:C ratio
üArchitectural disarray
üLoss of orderly differentiation
üDysplasia maybe precursor to malignant transformation but it does not
always progress to cancer
§Carcinoma in situ: when dysplasia is severe and involves full thickness of
epithelium but the lesion does not penetrate the basement membrane
üSeen in skin, breast, bladder and uterine cervix

23. Fig: Normal