LABORATORY EXAMINATION

• used to supplement the findings of the physical examination.

• requested in order to confirm or rule out possible diagnoses established from the clinical findings

• selection of the laboratory test should be based on what information the test will provide and the clinical significance of the results obtained

• A 71-year-old male patient was referred to the Universidade Federal do Paraná Stomatology and Maxillofacial Surgery outpatient clinic, Curitiba, Brazil, with a movable mass located in buccal mucosa region which was first noticed approximately 25 years earlier. The patient looked for treatment only because he lost his lower denture and wanted a new one. Extraorally, the patient had no detectable swelling. Because of the pedunculated aspect of the mass, the patient could move the mass extraorally

BIOPSY

BIOPSY

• refers to the removal , usually by surgical means , of living tissues for the purpose of microscopic examination

• most commonly used and reliable test available to the dentist

Indications

1. To establish a diagnosis in cases of suspected neoplastic disease

2. To confirm a clinical diagnosis which seems to be obvious ex. Epulis fissuratum

3. May be performed as a therapy for a patient with cancerophobia.

Contraindications

1. Extreme debilitation, cardiac disease, acute infection and undue bleeding tendency

2. Clinically obvious malignancy

Selection of the Biopsy Site

• to obtain tissue which is representative of the active lesion under study

• if the lesion overlies bone, the incision should be made down to bone.

• in cases of multiple, diffuse lesions, several smaller specimens properly identified will be of greater diagnostic value.

Types of Biopsies

Incisional Biopsy refers to the removal of a small portion of the lesion, usually a wedge-shaped or elliptical specimen

Excisional Biopsy refers to the removal of the entire lesion if a malignant neoplasm is expected but not clinically certain, generous lateral and deep margins of normal tissue should be obtained.

Punch Biopsy utilizes a specially designed instrument for the removal of a small segment of tissue. instrument may be forceps-like with cup-shaped cutting edges not used in the oral cavity.

a. Small size of the lesion

b. Likelihood of crushing the tissue .

Needle or Aspiration Biopsy refers to the removal of small bits of tissue or fluids from deep structures by means of a large-gauged needle used for deep-seated and relatively inaccessible soft tissue lesions

Care of the Biopsy Specimen

• proper handling of the specimen removed for histologic examination will greatly facilitate the preparation of the histologic sections.

• common artifacts caused by improper handling of the biopsy specimen include :

crushing drying improper fixation freezing

Important : 1. Care should be used not to crush the tissue with hemostats or other instruments used for immobilizing the tissue during surgical removal.

the tissue removed should be grasped at the extreme end with a tissue forceps

2. Excessive drying of the specimen will significantly alter cytologic detail and prevent a microscopic diagnosis.

to avoid drying, the tissue should be placed immediately in bottles with fixatives.

3. Freezing repeated freezing or

thawing may cause distortion of the cells

Preparation of the Biopsy Report

A written clinical history and description of the lesion to be examined should accompany the specimen to the laboratory.

age, sex, occupation of the patient the lesion should be carefully described , including measurements of size, and descriptions of color and consistency of the lesion

location of the lesion symptoms such as pain, or tenderness as well as duration of the lesion

Interpretation of the Biopsy Report

Written biopsy report consists : 1. microscopic description most important portion of the biopsy report

outlines in detail the features on which the diagnosis is made

• The histopathological analysis showed a circumscribed neoplasm constituted by mature adipose tissue surrounded by spindle-cells and a fibrous component. Cellular atypia were absent .

2. microscopic diagnosis should be consistent with the clinical features presented by the patient .

if not, further evaluation of the case by both the dentist and the pathologist is required.

possible cause: specimen submitted may not be representative of the disease and the biopsy must be repeated.

• Final microscopic diagnosis confirmed: simple lipoma.

• No recurrence was observed after three years follow-up .

Oral Exfoliative Cytology (Smear)

Exfoliative Cytology refers to the removal of surface cells for cytologic examination

Papanicolaou established a technique for the study of cevical smears that it became a recognized diagnostic procedure.

not greatly utilized in dentistry because biopsy is readily accomplished in the mouth.

Indications

1. patients who refuse biopsy or are poor surgical risks

2. cases in which biopsy is not planned

Contraindications

1. in cases of obvious malignancies no justification in delaying the referral for immediate histologic diagnosis and treatment

2. in cases of obvious keratotic lesions composed only of superfical keratinizing cells of no diagnostic value

3. deep seated lesions or masses which do not communicate with the surface

Advantages

1. ease with which the sample can be obtained

2. minimum equipment required. 3. convenient and no pain to the patient

4. ease of preparation of the specimen.

Disadvantages

1. definitive diagnosis is not obtained

only detects the presence or absence of malignant cells.

(+) diagnosis entails a second procedure (biopsy) to confirm the malignancy.

a. type of malignancy b. degree of differentiation

2. obscuring elements and poorly-preserved cells limit diagnostic accuracy

• studies have shown 15% false-negative rate

3. no value in hyperkeratotic lesion

4. (-) smear may give a false sense of security

prevents adequate follow-up

Oral Cytology Technique

The lesion should cleansed of debris

cells are obtained by scraping the surface of the lesion several times

scrapings are spread evenly over the central portion of the slide and are fixed immediately.

scrapings are fixed immediately

label the slide two smears should be prepared for each lesion to be examined .

submit to the laboratory along with the appropriate history

Remember: It should be emphasized that a negative cytology report is not a proof that a neoplastic disease does not exist.

If a lesion persists, biopsy should still be done.

The end

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