Oral Biopsies 2 Flashcards
When are apical lesions submitted into the laboratory as a sample?
following periradicular surgery (apicectomy)
Give examples of periapical lesions that can be submitted for microbiological examination
Most commonly:
* * radicular cysts
* periapical granulomas
Less commonly
* odontogenic cysts present at the apex e.g. nasopalatine duct cysts or odontogenic keratocyst
What is the purpose of fixing excised biopsy material in 10% formalin ?
this is to prevent tissue autolysis from occuring before the sample reaches the laboratory
What is the solution of choice for fixing tissue samples?
10% neutral buffered formalin (a 4% solution of formalin)
What is the problem with submitting apical lesions on gauze placed in formalin solution?
if the volume of formalin is not great enough then the gauze tends to absorb most of the formalin leaving the specimen dry and unfixed
it can also be difficult to seperate the specimen from the gauze
Although it is not essential, what should you courteously inform a pathologist of?
the inclusion of bone in the specimen
Hard tissue (teeth) samples should not be fixed in 10% neutral buffered formalin. True or false
False
They should be fixed in it
Why might a histopathology report for a hard tissue biopsy (tooth tissue) take weeks to come?
this is because decalfcification is required
What does the time for decalcification depend on?
- size of specimen
- consistency of specimen
In what instances is it best to undertake a biopsy in the hospital?
- if there is suspicion of a pre-malignant disease or tumour
- suspicion of widespread mucosal disease
What is the importance of a provisional clinical diagnosis of an oral lesion ?
- can inform or guide the technique and tissue handling that should be used
What should a biopsy to exclude malignancy in a long standing ulcer include ?
the biopsy of the ulcer and some adjacent clinically normal epithelium
What is the benefit of including clinically normal epithelium in the biopsy of a carcinoma?
it allows the coformation that the malignancy arises from the overlying epithelium rather than a deeper structure or a metastasis of a different site
it also allows the invasive front to be examined which can yield useful prognostic information
Why should the centre of large tumours be avoided in biopsies?
this ise because they are often necrotic and will not yield diagnostic material
What is a disadvantage of incisional biopsies of potentially malignant/premalignant lesions?
some studies have demonstrated the presence of cytokeratins in the blood of a few patients following incisional biopsy of an oral SCC
This demonstrates the dissemination of cancer cells which may result in metastasis
What has been suggested to mitigate the risk of blood borne metastasis following incisional biopsies of malignant tumours (including oral cancer) ?
administration of chemotherapeutic drugs prior to biopsy to minimise the risk of metastasis
Why should erosive lesions associated with lichen planus/lichenoid reactions not be biopsied?
this is because erosive areas show non-specific inflammarory changes associated with ulceration and will not be useful in diagnosis
What is the ideal site of biopsy for suspected vesiculobullous disorders?
the ideal site should be adjacent to the bulla where the epithelium is still intact
What samples should a pathology lab receive for a suspected vesiculobullous disorder?
- fresh sample plus (immunofluorescence)
- one that has been fixed in formalin
What is the ideal site of biopsy for desquamative gingivitis ?
intact area of mucosa which is often the attached gingiva
How would you go about the biopsy for desquamative gingivitis?
an elliptical area of the mucosa is incised and carefully dissected from the underlying periosteum with a Mithcell’s trimmer
What types of lesions have a higher incidence of dysplasia or malignant transformation?
- erythroplakia
- non-homogenous or speckled leukoplakia
Give an example of a method that can be used to prevent crush artefacts in biopsied tissue
- placing a suture within the mucosa (e.g. underneath the lesion) and holding the ends of the suture with artery forceps and tying loose knot above the mucosa
What is the importance of a loose knot being placed as opposed to a tight knot being placed when placing a suture before undertaking a biopsy?
a tight knot too close to the specimen may result in crushed tissue
What is the benefit of placing a suture before undertaking a biopsy?
- provision of traction
- prevent unwanted movement of tissue when taking biopsy from mobile structures such as the tongue
- can help pathologist orientate the biopsy sample for sectioning (if a diagram is provided on the pathology form)
When using the traditional technique for tissue handling, what must you ensure?
- [traditional technique is the use of tissue forceps]
- the area that is grasped using the tissue forcep must be away from the site of interest
A punch biopsy is an alternative to ________ biopsies
incisional
Briefly describe the punch used for punch biopsies
- consists of a circular blade attached to a plastic handle
- diameter of the circular blade ranges from 2-10 mm
How can the base of a punch biospy be released?
- simply and atraumatically using curved scissors
or - specimen can be lifted from the mucosal surface and the base undermined with a scalpel
What is the current benefit of punch biopsies over incisional biopsies ?
- fewer artefacts than conventional incisional biopsies
- however, it can be argued that placing a suture in incisional biopsies would also produce minimal artefacts
Why is it safer to use larger diameter punches ?
- avoids handling problems both clinically and in the laboratory
What type of sample is required for immunofluorescence?
fresh frozen sample
What types of samples are required for the diagnosis of vesiculobullous disorders?
- fresh frozen (immunofluorescence)
- formalin fixed
The length of an incisional biopsy should be …
3x the width of the biopsy
Incisional biopsies are often in the shape of an …
ellipse
Give examples of sites that are unsuitable for punch biopsies
- palatal
- gingival
- some lingual sites
The majority of mucosal biopsies are …
incisional
How can a biopsy be orientated?
placing a suture at one known margin e.g. anterior or superior margin
(diagram can follow this?; ask pedro)
The brush biopsy, a new technique for the oral cavity, has shown high sensitivity and specificity to detect dysplasia in multiple studies. True or false
false
only one large study from the U.S. has shown these results
What are the requirements of a biopsy for the diagnosis of Sjogrens syndrome?
labial biopsy with a minimum of 5 minor salivary lobules should be obtained
lower lips is often the site of choice
minimal sharp dissection of the area should be performed to lessen the chance of sensory nerve damage
What is the cause of mucoceles?
they arise from the blockage (with mucus) and subsequent rupture of the minor salivary gland duct
What is a requirement for the excision of mucoceles? Why is this?
- you must remove the associated minor salivary gland to preven recurrence of mucocele
What is a rare site for the occurence of mucoceles? What is the consequence of this?
- the upper lip
*thus, swellings in the upper lip should be treated as minor salivary gland tumours (and not mucoceles) until proven otherwise
What types of biopsy should be performed for palatal swellings suspected to be salivary tumours? Briefly state how these biopsies should be performed with reasons
- incisional biopsy
- done asdeeps as possible, down to the bone if appropriat as lesions can be a considerable depth beneath the mucosa and so a superficial biopsy can give a false negative result
What type of biopsy is contrainidcated with haemangiomas ?
incisional biopsy
State an appropriate biopsy for a small haemangiomic lesion
excisional biopsy
State an appropriate treatment for a large haemangiomic lesion of the lip
- ablated with either laser or cryosurgery
lack of material for histological examination as a result
What is a haemangioma?
vascular birthmark made of extra blood vessels in the skin
What techniques are advocated for obtaining biopsoes of extra-oral soft tissue swellings ?
Fine needle aspiration cytology (FNAC)
Fine needle cutting biopsy (FNCB)
What is the ideal volume of fixative in a specimen pot containing a biopsied sample?
volume of fixative should be 10x the volume of the specimen
How is formalin able to fix specimens?
by forming intermolecular bridges between proteins and cross-links with protein end-groups
What is a disadvantage of the protein cross-linking produced by formalin?
specimen is rended unsuitable for immunofluorescent antibody staining
antibodies- proteins
How are other histochemical staining methods (aside from immunofluorescence) able to be performed on fixed tissue?
the use of antigen retrieval
Give an example of a situation outside of immunofluorescence where fresh tissue is processed?
when frozen sections are useed to examine surgcal margins perioperartively
How should specimens for electron microscopy be fixed ?
they should be fixed in gluteraldehyde
formalin is an acceptable alternative
Some specimens for cytogenics may be required to confirm genetic changes in rare tumours e.g. synovial sarcoma. How should these specimens be transported?
they should be submitted in universal transport medium which has been stored at 4 degrees celsius
What is a downside of using a regional block as opposed to an infiltration before a biopsy?
the haemostatic (vasoconstrictive) effect of the adrenaline within the anaesthetic will be lost
What is the consequence of sampling tissues at the site of the local anaesthetic?
artefactual tissue oedema or distortion
e.g. bulla formation in gingival tissue or oedema which may lead to confusion in the diagnosis of crohns disease or orofacial granulomatosis where interstitial oedema is one of the diagnostic features
(misdiagnosis as crohns disease due to oedema present in gingival tissue as a result of harvesting a site containing LA solution)
remember crohns disease has oral manifestations
How should incisions for biopsies be made in respect to physiological structures such as nerve or blood vessels?
the incision should be made parallel to their expected position
How should incisions be made for biopsies in the palate?
incisions should run parallel to palatal nerves so should run anterio-posteriorly as opposed to across (medio-laterally)
What type of artefact is often associated with electrosurgical or laser cutting techniques?
Fulguration artefact
What is the resulting effect of a fulguration artefact?
- a layer of carbonised tissue
- a zone of thermal necrosis
- zone of tissue exhibits thermal damage
Electrosurgical and laser cutting techniques are not appropriate for…
diagnostic incisional biopsies
(they harm the diagnostic quality of the tissue)
Give an example of a polyglactin suture. State a benefit of this type of suture
Vicryl rapide
resorb more rapidly following placement of suture
Why has the use of catgut sutures ceased in the UK?
This is because there are acceptable synthetic alternatives
(consideration made to those that do not consume pork or pork product)
Suggest a material that can be used to cover gingival biopsy sites
- non eugenol periodontal dressing e.g. CoePak
If more than one specimen for one patient is placed in the same container, they must be marked. How can these specimens be marked?
- they can be marked by use of sutures
- do not rely on description of shapes as when they are fixed this can be altered
Outline some possible risks associated with biopsy procedures
- parasthesia of lips and tongue
- swelling and bruising
- procedures in FoM can lead to submandibular or sublingual duct damage
- removal of mucoceles from lips carry the risk of further gland damage and recurrence
What type of biopsy is appropriate for a chronic ulcer or SCC?
incisional biopsy of margin of ulcer
What type of biopsy is appropriate for a leukoplakia/erythroplakia?
incisional or punch biopsy of worst area
Consider multiple biopsies if extensive lesion
What type of biopsy is appropriate for a mucousal lichen planus?
incisional biopsy representative of the area
What type of biopsy is appropriate for a bullous lesion (pemphigus/pemphigoid)?
incisional or punch biopsuy of unaffected mucosa close to the bulla or erosion plus fresh tissue specimen
What type of biopsy is appropriate for granulomatous diseases (crohns, orofacial granulomatosis, UC, TB?
deep incisional biopsy plus fresh sample to microbiology if infective agent suspected
What type of biopsy is appropriate for a mucocele?
careful excisional biopsy
What type of biopsy is appropriate for a fibroepithelial polpy, pyogenic granuloma, epulis?
excision biopsy
What type of biopsy is appropriate for a minor salivary gland tumour in the palate?
deep incisional biopsy
What type of biopsy is appropriate for a minor salivary gland tumour in the upper lip?
excisional biopsy
What type of biopsy is appropriate for a major salivary gland tumour?
FNAC
FNCB
extra-oral soft tissue tumour
