Intro to Neoplasia Flashcards
Definitions:
- Neoplasia
- Tumor
-
Neoplasia:
- 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
- Tumor: “swelling”
How is a neoplasia different than hyperplasia?
neoplasia: unregulated, irreversible, monoclonal
- hyperplasia: regulated, reversible and polyclonal
Tumors: Benign vs. Malignant
-
Benign
- “-oma”
- Usually resemble normal tissue
- Slow growth rate
- Non-invasive, encapsulated
- Do not metastasize
-
Malignant
- Carcinomas or sarcomas
- Vary from resembling normal tissue to extremely different
- Variable growth rate
- Usually invasive
- Capable of metastasizing
Cell of origin: Epithelial
- Usually arise from ecto- or endoderm
- Squamous, glandular/ductal, respiratory, and transitional epithelium, liver cells, and basal cells of skin/adnexa
- May be benign or malignant:
- Colonic tubular adenoma
- Colonic adenocarcinoma
- Further classified based on architecture:
- Papillary
- Villous
Cell of Origin: Mesenchymal
- Arise from mesoderm
- Fibroblasts, adipocytes, smooth/skeletal muscle, bone, cartilage, blood vessels
- May be benign or malignant:
- Lipoma
- Liposarcoma
Cell of Origin: Mesenchymal
Nomenclature
- Fibro-
- Lipo-
- Leio-
- Rhabdomyo-
- Osteo-
- Chondro-
- Angio-
Cell of Origin: Hematolymphoid
- Lymphoma
- Leukemias
- Plasmacytoma
- Pseudolymphoma
- Malignant tumors
- Almost always malignant
Cell of origin: Melanocytes
- Melanocytic
- Neural crest origin
- May be benign or malignant:
- Nevus
- Melanoma
Benign epithelial tumors
- Squamous papilloma
- Adenomas (glandular epithelium)
- Tubular adenoma
- Ovarian mucinous cystadenoma
Benign mesenchymal tumors
- Lipoma (adipose tissue)
- Leiomyoma (smooth muscle)
- Hemangioma (blood vessels)
Benign mixed tumors:
Epithelial and mesenchymal components
- Pleomorphic adenoma
Teratomas
- Predominately benign tumors
- Composed of tissue derived from multiple germ layers
- totipotent cells (as opposed to previous tumors)
- Composed of tissue derived from multiple germ layers
Malignant epithelial tumors
- Esophageal squamous cell carcinoma
- Prostatic adenocarcinoma
- Urethelial carcinoma (bladder)
Malignant mesenchymal tumors
- Osteosarcoma
- Myxoid liposarcoma
Mixed Malignant Tumors
Carcinosarcoma of Endometrium (MMMT)
Tumor-like conditions: May mimic tumors clinically
-
Hamartoma
- Mass of disorganized, mature tissue which is specific to the site of development
- Represent anomalous development
- Example: lung hamartoma
-
Choriostoma
- Ectopic tissue in a foreign location
- Example: Gastric heterotopia
Differentiation/Grade:
- Defintion:
- Categories:
-
Definition:
- Extent to which tumor cells morphologically and functionally resemble the normal tissue counterpart
-
Categories:
- Well-differentiated: resemble normal tissue
- Moderately-differentiated: in between
- Poorly-differentiated: primitive, vague resemblance
- Anaplastic: complete lack of differentiation
- Benign tumors are almost always well-differentiated
- Malignant tumors vary from well- to poorly differentiated/anaplastic
Differentiation/Grade:
Well-diff
- Close resemblance to normal
- Evidence of maturation/function:
- Squamous cell carcinoma (SCC)
- Hepatocellular carcinoma (HCC)
Well differentiated vs. Poorly differentiated
Anaplasia
ANAPLASIA = UGLY
- Features:
- Pleomorphism (variety)
- Cellular
- Nuclear
- Hyperchromatic nuclei
- High N/C ratios
- Coarsely clumped chromatin
- Large nucleoli
- Atypical, bizarre mitoses
- Loss of polarity
- Tumor giant cells
- Pleomorphism (variety)
Spread of tumors:
Classification:
- In situ
- Locally invasive: malignant
- Metastatic: malignant
Carcinoma in situ (CIS)
- Pre-invasive lesion
- Frequently seen in proximity to invasive tumor
- Malignant cells do not penetrate beyond basement membrane
- Full thickness dysplasia
- Dysplasia: disordered growth
Dysplasia:
Dysplasia: disordered growth of epithelium
- Histologic diagnosis
-
Characteristics:
- Loss of polarity
- Loss of maturation
- Loss of architecture/organization
- “architectural anarchy”
- Abnormally located mitoses
- Varies from mild to severe (CIS)
- May spontaneously resolve (mild to moderate)
Morphologic features of dysplasia:
Mild → Severe (CIS)
Local Invasion:
A feature of malignancy
Spread of tumors: Metastasis
Metastasis- a criterion for malignancy
- Benign tumors do not metastasize!
-
Malignant tumors metastasize
- Exceptions: Basal cell carcinoma, Gliomas
-
Sites of mets:
- Lymph nodes
- Lungs
- Liver
- Bone (Vertebra)
- Brain
Pathways for metastatic spread:
Hematogenous
- Most common pathway for sarcoma spread
- Veins > Arteries
- portal vein ⇒ liver
- vena cava ⇒ lung
- paravertebral plexus ⇒ vertebral
Pathways for metastatic spread:
Lmyphatics
- Most common pathway for carcinoma spread
- Rarer event with sarcomas
- LN involvement predictable based on drainage
- Sentinel nodes: first LN to drain the tumor
Pathways for metastatic spread:
Seeding of body cavities and surfaces
- Peritoneal cavity most commonly involved
- Tumor cells displace from mass and implant and/or invade serosal surfaces
- Frequent finding in ovarian cancer, peripheral lung cancers
Clinical Staging of Tumors:
Clinical stage
- TNM system
- T=tumor size
- N=nodal involvement
- M=metastasis
- Each tumor has it’s own staging system
- Stage is not a grade
Host reaction to Cancer:
Physical Effects
- Local effects
- Cachexia
- “wasting syndrome”
- Hematologic abnormalites
- Anemia
- Hypercoagulability
- Paraneoplastic syndromes
Physical effects of Cancer:
Paraneoplastic syndromes
Paraneoplastic syndromes
- 10% of cancer patients
-
Non-hormonal or hormonal effects of a tumor, unrelated to local spread or metastasis
-
Exception examples:
- Hypercalecmia of skeletal metastasis
- Medullary carcinoma of the thyroid and hypocalcemia
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Exception examples:
