Kamis, 13 Oktober 2011

Principles and Techniques of Biopsy

It is important to develop a systematic approach in evaluating a patient with a lesion in the Oral and Maxillofacial region.

These steps include :
  • A detailed health history
  • A history of the specific lesion
  • A clinical examination
  • A radiographic examination
  • Laboratory investigations
  • Surgical specimens for histopathologic evaluation
Health History
An accurate health history may disclose predisposing factors in the disease process or factors that affect the patients management.
Up to 90% of systemic deseases can be discovered through history taking.
The same can be true of oral lesions when one is familiar with the natural progression of the more common disease processes.

Medical conditions that warrant special care include:
  • Congenital heart defects
  • Coagulopathies
  • Hypertension
  • Poorly controlled diabetics
  • Immunocompromised patients
History of the Lesion

Questions to Ask
  • Duration of the lesion
  • Changes in size and rate of change
  • Changes in the character of the lesion.
  • Lump to ulcer, etc
  • Associated systemic symptoms:               
  • fever                                                                                                    
  • nausea                                                                                
  • anorexia
More Questions to Ask
  • Pain
  • Abnormal sensations
  • Anesthesia
  • A feeling of swelling
  • Bad taste or smell
  • Dysphagia
  • Swelling or tenderness of adjacent lymph nodes
  • Character of the pain if present
Historical Reasons for the Lesions:
Trauma to the area
Recent toothache

Clinical Examination
  • The clinical examination should always include when possible:  
  • Inspection                                                                                          
  • Palpation                                                                                            
  • Percussion                                                                                         
  • Auscultation
Clinical Evaluation
  • The anatomic location of the lesion/mass
  • The physical character of the lesion/mass
  • The size and shape of the lesion/mass
  • Single vs. multiple lesions
  • The surface of the lesion
  • The color of the lesion
  • The sharpness of the boundaries of the lesion
  • The consistency of the lesion to palpation
  • Presence of pulsation
  • Lymph node examination
Radiographic Examination
The radiographic appearance may provide clues that will help determine the nature of the lesion.
A radiolucency with sharp borders will often be a cyst
A ragged radiolucency will often be a more aggressive lesion
Radiopaque dyes and instruments can help differentiate normal anatomy

Laboratory Investigation
Oral lesions may be manifestations of systemic disease.
If a systemic disease is suspected it should be pursued.

These include:
  • Tumor of hyperparathyroidism
  • Padgets disease
  • Multiple myeloma                          
  • Determination of serum calcium,phosphorus, and alkaline phosphatase and protein can be very useful in excluding certain pathological processes.
Indications for Biopsy
  • Any lesion that persists for more than 2 weeks with no apparent etiologic basis
  • Any inflammatory lesion that does not respond to local treatment after 10 to 14 days.
  • Persistent hyperkeratotic changes in surface tissues.
  • Any persistent tumescence, either visible or palpable beneath relatively normal tissue.
  • Inflammatory changes of unknown cause that persist for long periods
  • Lesion that interfere with local function
  • Bone lesions not specifically identified by clinical and radiographic findings
  • Any lesion that has the characteristics of malignancy
Characteristics of lesions that raise the suspicion of malignancy.
  • Erythroplasia- lesion is totally red or has a speckled red appearance.
  • Ulceration- lesion is ulcerated or presents as an ulcer.
  • Duration- lesion has persisted for more than two weeks.
  • Growth rate- lesion exhibits rapid growth
  • Bleeding- lesion bleeds on gentle manipulation
  • Induration- lesion and surrounding tissue is firm to the touch
  • Fixation- lesion feels attached to adjacent structures

What is a Biopsy?
Biopsy is the removal of tissue for the purpose of diagnostic examination. 

Types of Biopsy
  1. Oral cytology
  2. Aspiration biopsy
  3. Incisional biopsy
  4. Excisional biopsy
  5. Needle biopsy

Oral Cytology
Developed as a diagnostic screening procedure to monitor large tissue areas for dysplastic changes.
Most frequently used to screen for uterine cervix malignancy
May be helpful with monitoring postradiation changes, herpes, pemphigus.

The Disadvantage of oral cytological procedures include:
Not very reliable with many false positives.
Expertise in oral cytology is not widely available
The lesion is repeatedly scraped with a moistened tongue depressor or spatula type instrument.  The cells obtained are smeared on a glass slide and immediately fixed with a fixative spray or solution.

Aspiration Biopsy

Aspiration biopsy is the use of a needle and syringe to penetrate a lesion for aspiration if its contents.
To determine the presents of fluid within a lesion
To a certain the type of fluid within a lesion        
When exploration of an intraosseous lesion is indicated               

An 18 gauge needle on a 5 or 10 ml syringe is inserted into the area under investigation after anesthesia is obtained.
The syringe is aspirated and the needle redirected if necessary to find the fluid cavity.

Incisional Biopsy

An incisional biopsy is a biopsy that samples only a particular portion or representative part of a lesion.
If a lesion is large or has different characteristics in various locations more than one area may need to be sampled
Size limitations
Hazardous location of the lesion                                              
Great suspicion of malignancy
Representative areas are biopsied in a wedge fashion.
Margins should extend into normal tissue on the deep surface.
Necrotic tissue should be avoided.                                         
A narrow deep specimen is better than a broad shallow one.     

Excisional Biopsy

An excisional biposy implies the complete removal of the lesion.
Should be employed with small lesions.  Less than 1cm 
The lesion on clinical exam appears benign.        
When complete excision with a margin of normal tissue is possible without mutilation.                                                                                                 

Excisional Biopsy
The entire lesion with 2 to 3mm of normal appearing tissue surrounding the lesion is excised if benign. 

Principles of Surgery                                     
  • Block anesthesia is preferred to infiltration
  • When blocks are not possible distant infiltration may be used
  • Never inject directly into the lesion
Tissue Stabilization
  • Digital stabilization
  • Specialized retractors/forceps
  • Retraction sutures
  • Towel Clips
  • Suction devices should be avoided
  • Gauze compresses are usually adequate
  • Gauze wrapped low volume suction may be used if needed
  • Incisions should be made with a scalpel.
  • They should be converging
  • Should extend beyond the suspected depth of the lesion
  • They should parallel important structures
  • Margins should include 2 to 3mm of normal appearing tissue if the lesion is thought to be benign.
  • 5mm or more may be necessary with lesions that appear malignant, vascular, pigmented, or have diffuse borders.
Handling of the Tissue Specimen
  • Direct handling of the lesion will expose it to crush injury resulting in alteration the cellular architecture.
Specimen Care
  • The specimen should be immediately placed in 10% formalin solution, and be completely immersed.
Margins of the Biopsy
  • Margins of the tissue should be identified to orient the pathologist.  A silk suture is often adequate.  Illustrations are also very helpful and should be included.
Surgical Closure
  • Primary closure of the wound is usually possible 
  • Mucosal undermining may be necessary 
  • Elliptical incision on the hard palate or attached gingiva may be left to heal by secondary intention.
Biopsy Data Sheet
  • A biopsy data sheet should be completed and the specimen immediately labeled.  All pertinent history and descriptions of the lesion must be conveyed.
  • Intraosseous and Hard Tissue Biopsy
  • Intraosseous lesions are most often the result of problems associated with the dentition.
Indications for Intraosseous Biopsy
  • Any intraosseous lesion that fails to respond to routine treatment of the dentition.
  • Any intraosseous lesion that appears unrelated to the dentition.
Clinical Exam
  • Palpation of the area of the lesion with comparison to the opposite side.
  • Any radiolucent lesion should have an aspiration biopsy performed prior to surgical exploration.
  • Information from the aspiration will provide valuable information about the lesion.
  • Solid
  • Fluid Filled                                                                                                          
  • Vascular                                              
  • Without Contents           
Principles of Surgery
  • Mucperiosteal flaps should be designed to allow adequate access for incisional/excisional biopsy.
  • Incisions should be over sound bone
  • Cortical perforation must be considered when designing flaps
  • Flaps should be full thickness
  • Major neurovascular structures should be avoided
  • Osseous windows should be submitted with the specimen
  • Osseous preformations can be enlarged to gain access
  • Avoid roots and neurovascular structures
  • The tissue consistency and nature of the lesion will determine the ease of removal
  • Incisional biopsies only require removal of a section of tissue
  • Soft tissue overlying the lesion should be reapproximated following thorough irrigation of the operative site.
  • The specimen should be handled as previously described
Biopsy Results: What If ?
They don’t corroborate your clinical impression
Repeat the biopsy!!!     
Determine if the tissue was looked at by an Oral Pathologist      
The results show malignancy                     
When To Refer For Biopsy
When the health of the patient requires special management that the dentist feel unprepared to handle
The size and surgical difficulty is beyond the level of skill that the dentist feels he/she possesses
If the dentist is concerned about the possibility of malignancy

Biopsy in oral surgery

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