Neoplasia – Pathology · FCPS Part 1

One Liners

Prostate carcinoma drain into = internal iliac nodes
Commonest site of Nasopharyngeal carcinoma = Fossa of Rosenmuller
Most frequenct cancer due to ionizating radiation = Acute Lukemia
Esteogen Excess = Inc risk of Endometrial carcinoma / Breast
Type 1 neurofibromatosis most common associated tumor = Optic nerve Glioma
Risk of Carcinoma endometrium = DM
Carcinoma Cervix = Multiple sex partners
Abestosis = Brochiogenic carcinoma
hCG = Seminoma
Right superior lobe bronchus tumor = Apical superior bronchopulmonary segmented affected
EBV = Nasopharngeal
Metastatic calcifications most common = Vessels > Kidneys > Lungs > Stomach

Basic Definitions

Term	Definition
Neoplasm	Abnormal proliferation of cells that persists beyond normal growth regulation
Benign tumor	Neoplasm without invasive or metastatic behavior
Malignant tumor	Neoplasm capable of invasion and potentially metastasis
Carcinoma	Malignant epithelial tumor
Sarcoma	Malignant mesenchymal tumor
Metastasis	Spread of malignant cells to a distant site
Dysplasia	Abnormal cellular growth and maturation
Anaplasia	Marked loss of cellular differentiation

Tumor Nomenclature

Benign tumors

Generally named by adding the suffix -oma to the tissue of origin.

Tissue	Benign tumor
Fibrous tissue	Fibroma
Fat	Lipoma
Cartilage	Chondroma
Bone	Osteoma
Glandular epithelium	Adenoma
Squamous epithelium	Squamous papilloma

Malignant tumors

Tissue of origin	Malignant tumor
Squamous epithelium	Squamous cell carcinoma
Glandular epithelium	Adenocarcinoma
Fibrous tissue	Fibrosarcoma
Fat	Liposarcoma
Bone	Osteosarcoma
Cartilage	Chondrosarcoma

Important exceptions

Despite ending in -oma, these tumors are malignant:

Melanoma.
Lymphoma.
Mesothelioma.
Seminoma.

Exam tip: The suffix -oma does not always indicate a benign tumor.

Benign Versus Malignant Tumors

Feature	Benign	Malignant
Growth rate	Often slow	Often faster, but variable
Differentiation	Usually well differentiated	Variable, sometimes poorly differentiated
Borders	Often circumscribed	Frequently infiltrative
Local invasion	Absent	Present
Metastasis	Absent	May occur
Mitoses	Usually few and normal	May be numerous or atypical
Recurrence	Less likely after complete removal	Depends on tumor and treatment

Grading and Staging

Tumor grading

Grading describes histological features such as differentiation, mitotic activity and nuclear atypia.

Grade	General interpretation
G1	Well differentiated
G2	Moderately differentiated
G3	Poorly differentiated
G4	Undifferentiated/anaplastic

Grading systems vary by tumor type.

TNM staging

Component	Meaning
T	Size and/or local extent of primary tumor
N	Regional lymph node involvement
M	Distant metastasis

Remember: Grade describes microscopic appearance; stage describes extent of disease.

Carcinogenesis

Carcinogenesis is the process through which normal cells acquire genetic and epigenetic alterations that produce malignant behavior.

Chemical carcinogenesis

Stage	Main event
Initiation	DNA damage produces a potentially permanent mutation
Promotion	Proliferation of initiated cells
Progression	Additional changes produce increasingly aggressive behavior

Radiation carcinogenesis

Radiation	Main association
Ultraviolet radiation	Skin cancers
Ionizing radiation	DNA damage and increased risk of selected malignancies

Viral carcinogenesis

Virus	Associated malignancy
High-risk HPV	Cervical and oropharyngeal squamous cell carcinoma
EBV	Burkitt lymphoma, nasopharyngeal carcinoma and selected other tumors
HBV/HCV	Hepatocellular carcinoma
HHV-8	Kaposi sarcoma
HTLV-1	Adult T-cell leukemia/lymphoma

HPV

High-risk HPV types 16 and 18 are important oncogenic types.

E6 promotes degradation of p53.
E7 inactivates retinoblastoma protein (RB).

Dental relevance: HPV-associated oropharyngeal squamous cell carcinoma is particularly associated with high-risk HPV, especially HPV-16.

Oncogenes and Tumor Suppressor Genes

Oncogenes

Oncogenes arise from activated proto-oncogenes and promote cell growth or survival.

Gene	Association
RAS	Many carcinomas
MYC	Burkitt lymphoma
BCR-ABL	Chronic myeloid leukemia
HER2	Selected breast and other cancers
RET	MEN2 and selected thyroid cancers

Tumor suppressor genes

Tumor suppressors normally limit proliferation, support DNA repair or promote removal of damaged cells.

Gene	Association
TP53	Many cancers; Li-Fraumeni syndrome
RB1	Retinoblastoma
APC	Familial adenomatous polyposis
BRCA1/BRCA2	Hereditary breast/ovarian cancer predisposition
VHL	Von Hippel–Lindau syndrome
NF2	Neurofibromatosis type 2

p53

Often called the guardian of the genome.

Functions include:

Cell-cycle arrest after DNA damage.
Activation of DNA repair pathways.
Senescence.
Apoptosis when damage is irreparable.

MCQ tip: p53 mutation is among the most common genetic abnormalities across human cancers.

Tumor Markers

Tumor markers are useful for selected diagnostic, prognostic or monitoring purposes, but most are not sufficiently specific to diagnose cancer independently.

Marker	Major association
PSA	Prostate disorders, including prostate carcinoma
CEA	Colorectal and other carcinomas
AFP	Hepatocellular carcinoma and yolk sac tumors
CA-125	Epithelial ovarian carcinoma
CA 19-9	Pancreatic and biliary malignancies
β-hCG	Choriocarcinoma and selected germ-cell tumors
β₂-microglobulin	Multiple myeloma and some lymphoid malignancies
Calcitonin	Medullary thyroid carcinoma
Desmin	Skeletal and smooth muscle differentiation
Vimentin	Mesenchymal differentiation
Cytokeratins	Epithelial differentiation

Exam tip: Cytokeratin positivity supports epithelial differentiation, while vimentin is commonly associated with mesenchymal differentiation.