Neoplasia - Benign and malignant tumours nomenclature and difference.pdf

Nomenclature for benign and malignant tumors

1. Neoplasia
Presented by Prof Dilani Lokuhetty
Department of Pathology
Faculty of Medicine Colombo

2. Objectives
•Define the term neoplasia
•List the differences between hyperplasia and neoplasia
•Describe the concepts of nomenclature of benign and malignant
epithelial and connective tissue tumours, giving examples
•Discuss the differences between benign and malignant tumours
•Discuss the concept of borderline tumours

3. What is a neoplasm?
A neoplasm is a mass of abnormal
tissue formed as a result of
excessive, inappropriate,
purposeless, proliferation of cells.

4. Neoplasms
•Proliferation is not under the
control of normal regulatory
mechanisms - Autonomous
•Growth continues even if the
stimulatory factors are
withdrawn
•Though termed autonomous
neoplasms are dependent on the
host for blood supply, nutrition,
supporting stroma and
sometimes on hormonal
influence.

5. Hamartoma
A development abnormality which
contains haphazardly arranged
tissues which is normally found in
the organ of origin. One type of
tissue may predominate.
Pulmonary hamartoma

6. Choristoma
Choristoma is an island of
normal tissue at an ectopic site.
e.g. pancreatic acini and ducts in
the wall of the stomach.

7. Comparison of hyperplasia and neoplasia
Hyperplasia
•Physiological or
pathological
•Is controlled by normal
regulatory mechanisms
•Stops when the
stimulus is withdrawn
•May serve a purpose
Neoplasia
•Pathological
•Is not controlled by
normal regulatory
mechanisms
•Continues even if the
stimulus is withdrawn
•Purposeless

8. Endometrial hyperplasia and endometrial
carcinoma
Endometrial hyperplasia Endometrial carcinoma
Both will present with similar symptoms

9. Neoplasms
Neoplasms are composed of two
components
Parenchymal
component which forms
the proliferating part of
the tumour
Supporting stroma
Nomenclature is based on the proliferative part of the
tumour

10. Nomenclature
Histogenetic
component
Behavioural component
Gives information about the
type of cell from which the
tumour has arisen
Gives information whether a
tumour is benign or
malignant

11. NOMENCLATURE
Benign epithelial tumours
•Most benign tumours have
names with the suffix “oma”
preceded by the term indicating
the tissue of origin.

Names are given according to the
outstanding histological pattern

•Adenoma - glandular structures or
arising from glands
•Papilloma – finger like or papillary
processes
•Cystadenoma – hollow cystic masses

12. Adenomas and papillomas
Cystadenoma

13. Tumours may be further categorized according to site of origin
or type of epithelial cell giving rise to the neoplasm

Adenoma Thyroid adenoma
Colonic adenoma

Papilloma Squamous cell papilloma
Transitional cell papilloma

Benign epithelial tumours

14. Malignant epithelial tumours
• These are called carcinomas
- Adenocarcinoma
- Squamous cell carcinoma
- Transitional cell carcinoma

• Names may include the organ of origin, and an adjective
as well
- Clear cell carcinoma of the kidney
- Papillary carcinoma of thyroid
- Cholangiocarcinoma

15. Named after the cell of origin followed by the
suffix “oma”
- Haemangioma
- Lipoma
- Chondroma
- Fibroma
- Leiomyoma


Benign mesenchymal tumours

Haemangioma
Lipoma

16. Malignant connective tissue
(Malignant mesenchymal tumours)
Are named after the cell of origin, to which is added the suffix – ‘Sarcoma’
- Chondrosarcoma
- Fibrosarcoma
- Liposarcoma
- Osteosarcoma
Osteosarcoma
Chondrosarcoma

17. Exceptions to the normal rules of
nomenclature
Neoplasms that sound benign, but are really malignant!

- Lymphoma
- Melanoma
- Hepatoma
- Glioma
Follicular lymphoma
Melanoma

18. Leukaemias

•Leukaemias are neoplasms of
blood forming cells. They are
classified on the basis of their
clinical course (acute or chronic)
and the cell of origin
(Lymphocytic, myelocytic,
monocytic)

19. Benign mixed tumours
These have two proliferating
components.

Epithelial and mesenchymal components
- Fibroadenoma
- Mixed parotid tumour

20. Malignant mixed tumours
• Two epithelial components - Adenosquamous carcinoma
• Two mesenchymal components - Malignant fibrous histiocytoma
• Epithelial + mesenchymal components - Carcinosarcoma

Probably occurs due to divergent differentiation of a single line of
parenchymal cells.

21. Neoplasms of totipotent cells
A totipotent cell is a cell that is capable of differentiation into
any type of cell in the body. In postnatal life the only totipotent
cells are germ cells
Totipotent germ cell
No differentiation
Minimal epithelial differentiation
Retain germ cell
Characteristics (seminoma,
germinoma)
Solid masses of poorly
differentiated epithelial cells
(Embryonal carcinoma)
Neoplastic germ cell
Seminoma

22. Neoplastic Germ Cell
Somatic differentiation Trophoblastic
differentiation
Yolk sac differentiation
Mature and immature
tissues of all 3
embryonic
germ layers
Cytotrophoblast &
syncytiotrophoblast
cells
Teratoma Choriocarcinoma
Yolk sac tumour
(carcinoma)

23. Teratoma

24. NEOPLASTIC GERM CELL TUMOURS
Germinoma
seminoma
Embryonal
carcinoma
Teratoma
Choriocarcinoma
Yolk sac
carcinoma
Mixed germ cell tumour

25. Neoplasms of embryonal pluripotent cells
Embryonal pluripotent cells are found in the foetal period
and during the first few years of postnatal life. They can
mature into several different cell types.
The tumours are called “blastomas”
e.g.
Kidney Nephroblastoma
Retina Retinoblastoma
Adrenal Neuroblastoma
Liver Hepatoblastoma
Nephroblastoma
Blastomas are composed of primitive cells
with scanty cytoplasm and dark staining
nuclei.

26. Neoplasm is a term applied to benign and
malignant tumours
The term CANCER includes all types of malignant
neoplasms
(cancer and carcinoma are two different terms)

27. Objectives
•Define the term neoplasia
•List the differences between hyperplasia and neoplasia
•Describe the concepts of nomenclature of benign and malignant
epithelial and connective tissue tumours, giving examples
•Discuss the differences between benign and malignant tumours
•Discuss the concept of borderline tumours

28. Differences between benign and malignant tumours

Benign
•No local invasion or infiltration -
Mobile on palpation
•Well demarcated masses.
•May be encapsulated.
•So can be surgically enucleated.

Exceptions:
Haenangiomas are unencapsulated

Malignant
•Invade or infiltrate surrounding
tissues - Fixed to surrounding
structures
•Not well defined from the
surrounding tissues.
•So cannot be surgically enucleated.
•Some malignancies arise from a pre-
invasive or carcinoma in situ stage.

29. Benign encapsulated tumour
Follicular adenoma of thyroid
Benign unencapsulated
tumour- leiomyoma of uterus

30. Poorly circumscribed benign tumours
Soft tissue
haemangioma
Intramuscular
lipoma

31. Malignant tumours

Breast carcinoma Lung carcinoma Renal cell carcinoma
Osteosarcoma

32. Differences between benign and
malignant tumours

Benign
•Rate of growth is slow and
progressive.
•May come to a stand still or
regress.

Exception:
Some benign tumours may
grow rapidly.


Malignant
•Grow rapidly and erratically.

•Most undifferentiated
tumours usually have the
highest growth rate.



Growth rate depends on blood supply, availability of hormones etc.

33. Sometimes benign tumours may enlarge rapidly/ lead to acute
presentation
•Leiomyomas during pregnancy
•Bleeding into a benign tumour
•Oedema of a benign tumour due to torsion
•Bleeding from a benign tumour into a body cavity.
•Intussception of intestines due to a benign tumour

34. Differences between benign and malignant tumours

Benign
•Contain well formed blood
vessels
•Necrosis is unusual. Other
degenerative changes may be
present.
Exception:
Some benign tumours may
undergo haemorrhagic infarction



Malignant
•Contain numerous ill
formed blood vessels.
Some lack an endothelial
lining

•Necrosis and haemorrhage
are common.

35. Renal cell carcinoma
Thyroid carcinoma
Hepatocellular
carcinoma

36. Haemorrhagic infarction
of a leiomyoma

37. Differences between benign and malignant tumours

Benign
•Do not metastasize


Malignant
•Spread by blood stream and lymphatics (metastasize).
•large tumours are more likely to metastasize.

Exception:
Some malignant tumours locally invade but show a
reluctance to metastasise

38. Metastatic tumours in lung and liver

39. Malignant tumours that do not metastasize
•Basal cell carcinoma of
skin
•Most primary malignant
tumours of the CNS

40. Differences between benign and malignant tumours

Benign
•Do not show
microscopic evidence of
invasion of surrounding
tissue



Malignant
•Shows microscopic
evidence of invasion
of surrounding tissue

41. Microscopic differences between benign and malignant
tumours
Malignant tumours show invasion (range from microscopic invasion
of basement membranes to deep, destructive invasion).
Basal cell carcinoma Squamous cell carcinoma
Adenocarcinoma colon

42. Perineurial invasion Perineurial invasion
Vascular invasion
Capsular invasion

43. Differences between benign and malignant tumours

Benign
•Well differentiated
(structure and function
resemble tissue of origin).

e.g. Thyroid adenoma,
Lipoma


Malignant
•Vary from well differentiated to
highly undifferentiated or
anaplastic.
Function may be abnormal.
e.g. Production of fetal proteins
or hormones

44. Benign tumours

Lipoma

Leiomyoma Thyroid adenoma

45. Sometimes the structure and function of benign
tumours may differ from normal tissue.
The gross and microscopic
appearance of a benign tumour
may depart from normal and
assume papillary or polypoidal
configuration.

46. Sometimes the structure and function of benign tumours
may differ from normal tissue.
Mucinous cystadenoma of ovary
Embryonal or fetal adenoma
of thyroid

47. Malignant tumours
Well-differentiated
Moderately-differentiated
Poorly-differentiated

48. Cellular atypia and pleomorphism
•Cells vary in size, shape and in their relationship to
one another (pleomorphism).
•Nuclei are enlarged.
•High nuclear :cytoplasmic ratio (normal – 1:4 or
1:6, in malignancy it is about 1:1)
•Chromatin is coarsely clumped and distributed
along the nuclear membrane.
•Nucleoli are large, indicating synthetic activity.

49. Cellular atypia and pleomorphism

•Nuclei are dark and
hyperchromatic due to
increased DNA.
•Tumour giant cells have
a single huge nucleus or
multiple nuclei.

50. Differences between benign and malignant tumours

Benign
•Mitotic figures are rare and
normal in appearance.



Malignant
•Mitotic figures are
numerous and may
be abnormal.

51. Differences between benign and malignant tumours

Benign

•DNA content is
usually normal.
•Karyotype is
usually normal.



Malignant

•DNA content is increased
(aneuploidy or polyploidy).
•Additional chromosomes,
deletions or translocations may
be present.

52. Anaplasia
Tumours that are
composed of
undifferentiated
cells are called
anaplastic.

53. Function of malignant tumour cells
•Well-differentiated tumours may show normal function.
•Production of normal hormones by pituitary adenomas.
•Production of keratin by squamous cell carcinomas.
•Production of bile by hepatocellular carcinomas
•May show abnormal functions.
•Lung cancers may produce ACTH
•Production of fetal hormones and antigens (e.g. CEA by bowel cancers, alpha-feto protein by
hepatocellular carcinoma)

54. Dysplasia
An atypical disorderly
proliferation of cells where
the cells display all the
features of dysplasia but the
cells do not invade the
basement membrane.
Dysplastc cells in a
smear

55. Dysplasia
•Dysplasia is not synonymous with
cancer.
•Mild to moderate dysplasia
which does not involve the full
thickness of the epithelium may
regress completely especially if
the inciting causes are removed.

56. Carcinoma in-situ
•All the cytological features of
malignancy, including abnormal mitoses
are seen in an epithelium.
•But there is no penetration of the
basement membrane.
•Histologically it is impossible to
differentiate severe dysplasia and
carcinoma in situ.
•But clinically this is not important as
both are treated in the same way.

57. Borderline tumours
A borderline tumor, sometimes
called low malignant potential
tumor, is a distinct but yet
heterogeneous group of tumors
defined by their histopathology as
atypical epithelial proliferation
without stromal invasion.
•Borderline serous and mucinous
tumours of the ovary.
•Smooth muscle tumours of
unknown malignant potential
(STUMP) in the uterus.

58. Behaviour of soft tissue tumours
• Benign tumours
•Leiomyoma, haemangioma
• Malignant tumours
•Leiomyosarcoma, angiosarcoma
• Intermediate locally aggressive tumours
•Atypical lipomatous tumour, fibromatosis
•Intermediate rarely metastasizing tumours
•Dermatofibrosarcoma protuberans, Kaposi sarcoma

59. Objectives
•Define the term neoplasia
•List the differences between hyperplasia and neoplasia
•Describe the concepts of nomenclature of benign and malignant
epithelial and connective tissue tumours, giving examples
•Discuss the differences between benign and malignant tumours
•Discuss the concept of borderline tumours

60. Thank you