Anatomic Pathology Readings 1-5 Flashcards
level of disagreement of clinical and pathologic diagnosis using necropsy
1/3
has accuracy of dx improved?
not significantly
what types of cases would a PM be most rewarding
-sudden, rapid, progressive diseases (ECC service)
-complexity of internal medical disorders
(ophtho, dentistry, derm- usually never sent to PM and cardio usually supportive of clinical dx) –> although derm is most often incorrect in their full diagnosis
why is PM useful?
- method of quality control- check clinical dx
2. continuing education
t/f- there is a statistical significance in how much a case is worked up vs. autopsy descrepensy
false- cases that are worked up significantly don’t nec. decrease the discrepsency of PM findings
Benign epith tumors
adenomas, papillomas
-epithelioma, trichoepithelioma, chemodectoma
-basal cell tumour
Usually benign -> cutaneous extramedullary plasmacytomas and grade 1 mast cell tumors
t/f basal cell tumor usually benign
true
List 4 benign mesenchymal tissues
fibroma, osteoma, lipoma, hemangioma
Are lymphohistiocytic tumors usually benign?
no except histiocytoma
t/f MCT grade 1 and plasmacytomas are malignant but clincally benign
true
Give 2 exceptions to the rule that benign tumours will grow slowly.
Canine cutaneous histiocytoma or sebaceous gland adenoma (growing quickly as a 2nd effect to the trauma of licking)
Give 4 examples of benign tumors=death b/c location
- meningloma –> brain pressure
- thymoma –> respiratory compromise
- leiomyoma- GI dysfxn
- hepatocell adenoma –> large, necrotic & rupture
- pituitary, thyroid adrenal gland adenomas –> hormones
What are 4 cell features of benign tissue?
low N:C
nuclei size uniform
small nucleoli
low mitotic rate
Exception to benign generalization of low mitotic rate
histiocytoma
Malignant epith tumours are called
carcinoma, adenocarcinoma
Carcinomas create intense stromal rxn called
desmoplasia (growth of fibrous tissue) or scirrhous reaction= high malignancy
malignant mesenchymal tissue is called
sarcoma
t/f melanoma can be malign or benign
true!
variation in nuclear shape called
pleomorphism
exception to rules of highly malignant tumors
biologically high grade fibrosarcoma of canine head:
- well differentiated, poorly cellular, low mitotic rate BUT
- invasive, aggressive behavior
List 3 tumour types with benign histo but invasive malignancy
pheochromocytoma (vascular tumour of the adrenal medulla)
thymoma
sertoli
granulosa
Tumours which appear malignant on histo but don’t behave like it
seminoma
dysgerminoma
Is there grading accuracy in small biopsy samples?
no - tumours can be very heterogeneous
List 5 graded tumors
MCT (mast cell tumour) STS (soft tissue sarcoma) TCC (transitional cell carcinoma) Hemangiosarcoma Ocular Melanoma
(mast cell tumour, soft tissue sarcoma, synovial cell sarcoma, primary lung carcinoma, transitional cell carcinoma, multilobular osteochondrosarcoma, dermal and ocular melanoma, mandibular osteosarcoma, hemangiosarcoma, and squamous cell carcinoma of the tongue)
Is grading these tumours useful? cutaneous plasmacytoma, chondrosarc, endocrine carcinoma
no (For these tumors, grading schemes have been tried, but fail to correlate with clinical outcome or response to therapy)
Describe the staging of tumours using the TNM system
T-extend of primary tumour
N- regional LN
M-met
You can use this stain to help distinguish mucin in poorly differentiated adenocarcinomas
PAS (periodic acld-Schiff) stain
Stain for MCT granules
toluidine blue
Masson’s trichrome stain is used to distinguish
muscle from collagen
Test to further distinguishes btwn diff classes or types of neoplasia
IHC ( Identify various cellular structures such as intermediate filaments and proteins.)
Best method for marking tumors to find if it was a complete excision
ink (sutures or staples need to be removed before processing)
Describe the Enneking classification of margins
an intracapsularmargin is one in which cells extend to the surgical margin
vs. marginalmargin is one in which reactive tissue is at the margin
vs. wide- surrounded by healthy tissue (1-3cm) but within compartment of origin
vs. radica l- entire compartment removed
t/f even with wide and radical margin, still 10% recurrance rate
t
Avoid these areas when taking a biopsy
necrosis and inflammation
bx sample put in what
10% formalin 1:10 buffered formalin
What is the sample slice size with a large sample?
bread-loaf 1cm thickness, leaving one side in-tact
How should you send cytology slides?
Unstained and not exposed to formalin fumes
Reactive and inflammatory tissue that is sent into a pathologist can be mistaken for what?
Reactive tissue and inflammation can be mistaken for neoplasia, or inflammatory process may mask underlying neoplasia.
Does the statement “pathologic and histologic interpretation is more art than science” have merit
yes, when dealing with tumor dx
What can one hope to learn from surgical biopsy?
- type, severity, and extent of tumour
- helps you choose appropriate treatments and determine prognosis
Biopsy techniques fall into 2 categories
- pre-treatment
2. post-treatment or excisional
t/f there is evidence that a properly performed bx can negatively impact survival or spreading of cancer
false- no evidence
3 indications for doing a pre-treatment biopsy:
- type of tx altered by histo grade
2.lesion is in area diff to reconstruct or definitive tx carries risk - if knowledge changes outcome of willingness to treat
(In general, for most externally accessible masses, it is best to biopsy before initiating treatment even if the treatment will eventually involve surgical removal of the mass)
When is a pretreatment biopsy contra-indicated?
- If it won’t change choice of therapy
- If the biopsy procedure is as difficult or dangerous as the definitive surgery, such as with brain or spinal cord biopsy.
Where is the best area of sampling a tumour?
The junction of normal-abnormal (except if primary bone tumor)
Primary bone tumors are exception to rule about sampling junction of abN-N- where should you sample?
middle of tumor
When should you take a needle core bx (Tru-cut)?
- externally accessible masses
- liver, prostate, kidney with US
- SQ, dermal
For sampling cutaneous lesions use:
-Punch biopsy 2-6mm
Larger masses, possibly inflamed or ulcerated should be sampled how?
Incisional bx (a wedge of tissue is taken from the mass)
Intramuscular bx should be sampled how?
open (wedge)
Carry out an excisional bx when?
- cytology reveals benign lesion
- reexisision can be obtained with 2-3cm margins
Which LN bx can be tricky and why?
submandibular can be normally enlarged and are close to salivary gland which can look like neoplastic cells
Why take a LN bx?
Differentiate lymphoma vs. reactive lymph node hyperplasia
Why take a bone bx?
Figure out if it is neoplastic vs infectious
Name 2 types of bone bx and the cons of each
Michelle Trephine - needs surgical approach (more soft tissue disruption) and a larger hole created causing a greater risk path fracture
Jamshidi- smaller biopsy (less disruptive, but you get less), less decalcification required so faster turn-around time.
When diagnostics point to wanting to stage a diffuse, non-resectable disease OR an open surgical biopsy is dangerous- use which technique?
endoscopic, laproscopic
Endoscopic/laproscopic is especially useful with what areas?
hollow organs and airways
Which disease was most disputed with pathologists re: toe amputations?
keratoacanthoma (reported commonly as sq. cell carcinoma)
Cellular features of a malignant tumour:
- a high nuclear/cytoplasmic ratio
- extensive vanation in nuclear and cytoplasmm size (ansiokaryosis and ansiocytosis, respectively)
- variation in nuclear shape (pleomorphism)
- large nucleoli
- high mitotic rate
