Neoplasia #2: Classifications of Cancer, Tumor Spread, and Grading vs. Staging

4 major classifications of cancer

Carcinoma, sarcoma, melanoma, and lymphoma/leukemia

What are carcinomas?

Carcinomas are malignant tumors of

• epithelial surfaces

• organs with epithelial-lined ducts/glands

• Endocrine glands (I.e. thyroid)

Carcinomas are positive for

cytokeratin immunostains!!!!!

What is desmoplasia?

Fibroblast reactive proliferation to create collagen (non-neoplastic)

• Fibroblasts themselves are not malignant

On cut section, tumor fibrosis appears white/gray

** Characteristic of carcinomas

Remember: not the same as capsules (which is a feature of benign tumors)

Carcinomas are described as

polygonal

What is adenocarcinoma?

Invasive carcinomas that form glandular configuration 

• Example: ductal carcinoma in situ (DCIS) - adenocarcinoma that has NOT breeched the basement membrane of the glandular epithelium

What is squamous cell carcinoma?

Carcinomas that form solid nests of cells with: distinct borders, intercellular bridges, and pink keratinized cytoplasm

Characteristic feature of squamous cell carcinoma

• Create keratin pearls/whirls

• Cytokeratin positive stain

What is ductal breast cancer?

Cancer from glands that carry milk to nipple

** BRCA1 and BRCA 2 are associated with hereditary cases. 

What is lobular breast cancer?

Cancer from lobules that produce milk (connects to ducts)

70-80% are invasive ductal

** BRCA1 and BRCA 2 are associated with hereditary cases. 

Breast adenocarcinoma

Invasive breast carcinoma

Lobular - cells like to line up one behind the other

Disordered and atypical

Cervical squamous cell carcinoma

• Starts in transition zone - transition from endocervix to exocervix

  • Columnar → squamous

• Starts as dysplasia (not full thickness atypic)

  • Progresses to squamous cell carcinoma in situ

  • Progresses to invasive squamous cell carcinoma

Cervical dysplasia histology

Cervical carcinoma in-situ histology

Fully atypical cells from base to apical surface

Cervix normal vs squamous carcinoma in situ histology

Invasive squamous cell carcinoma

KERATIN PEARLS!

Keratin is really bright pink

“Round nests” usually indicates invasive 

Well-differentiated invasive squamous cell carcinoma

Should be able to to identify this easily!!!!

Poorly-differentiated squamous cell carcinoma

Cell sizes are very different

No pearls/nests

Cytokeratin stain would prove whether it is a carcinoma or not

Mitotic figures

Colonic polyp

Growth above epithelium

Can be benign or precursor to malignancy

** Tubular adenoma - usually benign polyp

Colonic polyp - tubular adenoma histology

Colonic adenocarcinoma

Histiogenesis of sarcomas

• Arise from soft tissue (CT - components of mesoderm)

  • Examples: nerves, muscle, fat, bone, cartilage, fibroblasts, blood vessels

• Generally big and “fleshy fish”, soft → no desmoplasia

What are the boards description for sarcomas?

Cells are very pleomorphic and spindle-shaped

Sarcoma histology

Leiomyosarcoma histology

Smooth muscle tumor

What stains are positive in leiomyosarcoma?

Immunostains: vimentin positive (sarcoma - mesoderm origin) and desmin (muscle)

Vimentin (sarcoma) + desmin (muscle) =

Leiomyosarcoma

Vimentin (sarcoma) + S100 (nerve) =

Malignant nerve tumor

Vimentin (sarcoma) + CD31 (vessel) =

Angiosarcoma

Anaplastic tumor

LACK OF DIFFERENTIATION

“Mixed tumor” of parotid gland

• Also called = pleomorphic adenoma (benign)

• Two cell types/lineages appear to be present 

Teratoma of ovary has ___ tissue from ___ cell lines/germ layers

Teratoma of ovary histology

Define “mixed tumor”

2 types of tissue from the same germ cell line/layer

Define teratoma

At least two cell types from at least 2 different germ cell lines/layers

What are the four ways for tumors to spread?

1. Direct extension

2. Lymph channels to nodes (typical of carcinoma)

   1. Exception: renal cell carcinoma and hepatocellular like to spread via the venous system

3. Blood vessels (typical of sarcomas) → spread faster and farther

4. Seeding within body cavities

   1. On the surface of organs, wherever fluid in the cavity touches

What happens with removal of all axillary nodes?

Can’t clear infection through lymphatics 

** Never put IV on the same side of breast cancer because of this removal

GI carcinomas metastasize to the liver via

venous blood drainage d/t draining proximity to the liver

What is grading?

• Histologic feature of a tumor that determine how differentiated a tumor is

• How much does it resemble corresponding normal tissue?

• Think: when grading papers, you compare to answer key and think how does it resemble it

What is staging?

• How far has the tumor spread in the body

• Requires entire patient 

• Think: staging a patient

Stage vs grade - which is more important?

Stage is more important than grade - important for prognosis/outcomes

** One exception: chondrosarcoma - grade of tumor is more important that stage

Tumor grade — progression

Well differentiated → moderately differentiated → poorly differentiated → anaplastic

Higher grade = worse prognosis!!

Basic criteria of staging

• In situ→ micro-invasion → local invasion

TNM system

T - tumor

N - lymph node

M - metastases

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