Procedures in Oral Medicine

Procedures in Oral Medicine

Michael Escudier and Saman Warnakulasuriya

Introduction

  • A differential diagnosis is drawn by the clinician based on the history and an oral examination.
It consists of a list of possible diagnoses.
  • A definitive diagnosis can be made for some oral conditions (Table 14.1) with pathognomonic clinical appearances.
Pathognomonic means characteristic for a particular disease.
  • Other pathological conditions may present as lumps, ulcers, bullae, white, red or pigmented patches and require special investigations.
Bulla means a large vesicle, similar to a blister, containing serous or seropurulent fluid.
  • The objective of the investigations is:
    • To establish a definitive diagnosis.
    • To inform the selection of an appropriate intervention.
    • To monitor the response to intervention.
The selection of the appropriate test is underpinned by the judgement and experience of the clinician.
  • Investigations include: biopsy, imaging, haematological, serological or immunological investigations and culturing for microbes.
  • Any investigation is undertaken with the clear consent of the patient.

Table 14.1 Conditions that may not require biopsy to confirm the diagnosis.

Condition Description
Geographic tongue A history of migration of patches and classical appearance of a depapillated patch(es) with a buff‐coloured rim.
Frictional keratosis and linea alba buccalis White patch along occlusal line; clear evidence of trauma to the site.
Leukoderma Bilateral white/grey appearance of buccal mucosae that disappears on stretching.
Denture‐induced stomatitis Red patch covering denture‐bearing zone.
An amalgam tattoo Pigmented area in close contact with an amalgam restoration.
Papillitis; an enlarged lingual tonsil Posteriorly located on lateral margin of tongue is an anatomical variation.
Central atrophy of tongue papillae
(*median rhomboid glossitis)
A patch of depapillation of dorsal tongue.
Reticular lichen planus Clinical appearance with striae is often sufficient to enable this diagnosis.

* This term is now obsolete.

Biopsy

  • Failure to diagnose is a leading cause of dental malpractice litigation (Melrose, 2011).
  • Biopsy is particularly indicated when the clinical appearance is indicative of a range of conditions.
Biopsy is the removal of a tissue sample for pathological examination.
  • Biopsy facilitates light microscopic analysis by a histopathologist.
Oral soft tissue lesions often require a biopsy to confirm the diagnosis. Biopsy is also advisable for bone disorders which cannot be diagnosed by radiographic imaging alone.
Biopsy Techniques
  • Several different techniques are available (Table 14.2).
A standard biopsy ‘kit’ for the incisional or excisional technique using a knife is shown in Figure 14.1.

  • Biopsy kit: mirror, Mitchell’s trimmer, blade handle, tissue forceps, needle holders, suture scissors, curved mosquitoes/clip, Lac and Kilner retractors, galipot, sterile gauze, sterile foil, sterile drape.
  • Biopsy extras: 15 blade, 4‐0 sutures, syringe handle, local anaesthetic cartridge, needle, biopsy specimen pot, suction tubing, suction tip.
The technique should be appropriate for obtaining a tissue diagnosis with minimum discomfort and complications to the patient.
  • Techniques available for biopsy of soft tissue lesions include:
    • Excisional.
    • Incisional.
    • Punch.
    • Brush.
    • Fine needle aspiration.
Excisional Biopsy
  • Generally small lesions (e.g. <~2 cm at their widest diameter) may be excised thereby providing tissue for diagnosis as well as accomplishing the treatment at one visit.
Examples include: fibroepithelial polyps, benign squamous papillomas, mucoceles and denture‐induced granulomas.
  • An excised sample must always be transported to a pathology laboratory rather than be disposed of.
Why? At times, unexpected tissue diagnosis may occur requiring revision of the original clinical diagnosis.
  • An excisional biopsy is not indicated when malignancy is suspected, however small the lesion.
Why? It may result in poor margin clearance, and obliterating the site of the primary lesion may make it difficult for a surgeon to operate at a later time.
Incisional Biopsy
  • Performed to sample a mucosal lesion that is large.
What shape is best? A wedge or an ellipse of tissue from the most representative area taking into consideration the optimal wound closure by suturing the defect.
  • The sample is transported to the pathology laboratory to be analysed.
  • No clear contraindications to undertaking a biopsy in a surgical setting. However, there are some conditions where the decision to proceed with biopsy should be made with caution.
When? Bleeding diathesis secondary to anticoagulation, lesions located near vital structures that could be injured (e.g. near the submandibular duct orifice, near the mental nerve exiting at the foramen).
  • Some lesions, e.g. suspected tumours of minor salivary glands of the palate and particularly of the upper lip should not be subjected to incisional biopsy unless such biopsies are performed by a specialist.
Why? To avoid any seeding of tumour cells which could adversely affect the future prognosis of the case (Kusukawa et al., 2000).
Site Selection
  • Critical to include the most representative part of a lesion, particularly if the affected area lacks a homogeneous appearance.
Why? In a mixed white/red patch consistent with the clinical diagnosis of erythroleukoplakia the red zone may demonstrate by histology a higher grade of dysplasia compared with white (simple keratoses) or even an early carcinoma.
  • An incisional biopsy should always include a margin of normal tissue.
Why? A suspected squamous carcinoma where its rolled margin extends to ‘normal’ mucosa may show invading islands of malignancy that may be missed in the centre due to the friable nature of an invading carcinoma.
  • If the disorder involves a large mucosal patch and there is a varied clinical appearance, more than one biopsy sample may be helpful for the pathologist to report upon.
In such cases a good choice is to use a punch biopsy to take at least two samples. The technique is described later.
  • Incorrect sampling is often the reason for missing a malignancy or, for example, underdiagnosis of oral epithelial dysplasia.
Those with less experience should consult with a senior colleague before selecting the site from which an incisional biopsy is taken.
Biopsy Procedure and Technique See Figure 14.2.
  • Informed consent is essential prior to undertaking the procedure.
  • After giving an adequate local anaesthetic the patient should be reassured regarding pain control during the procedure.
Some anxious individuals may opt for intravenous sedation (Chapter 10) to comply with the procedure.
  • Some operators prefer to remove tissue samples by laser.
Why? The main advantage is bloodless surgery and favourable wound healing. The CO2 laser has been recommended to treat by excision benign oral lesions, e.g. fibromas, papillomas. However, when used for incisional biopsy of leukoplakia or erythroplakias thermal damage to margins may preclude valuable microscopic information and a pulsed char‐free mode is recommended (Suter et al., 2010).
  • Removal of sufficient tissue in terms of extent and depth is important.
Why? The pathologist requires a large enough specimen and small biopsies may shrink by a third when immersed in the fixative.
The depth is important as superficial oral biopsy samples, particularly when lacking any connective tissue, cannot be interpreted when reporting, e.g granulomatous conditions: granulomas are found often deep in the lamina propria.
  • Orientation of the biopsy with a stitch and a labelled diagram may help the pathologist to interpret its anatomical location.
  • Any blood exudate on the surface should be wiped by placing the sample on a wet gauze to reduce any blood contamination.
  • Issues pertaining to transport of specimens for immunological tests are described later.
Labial Gland Biopsy
  • This procedure involves sampling minor salivary glands in the lower lip.
  • The three main indications for performing a labial gland biopsy are to:
    • Investigate xeostomia with a view to confirming Sjogren’s syndrome.
    • Assess infiltrative diseases in connective tissue, e.g. sarcoidosis and amyloidosis.
    • Diagnose chronic graft versus host disease (cGVHD).
Rarely, IgG4‐related disease may be confirmed on the basis of a labial salivary gland biopsy.
  • The technique was originally described by Chisholm and Mason in 1968.
  • A systematic review (Colella et al., 2010) found 21 articles describing various surgical techniques for taking a lip biopsy and complications involved.
The most commonly used technique (Greenspan et al., 1974) involves a 1.5–2 cm linear incision in the normal lower lip mucosa parallel to the vermillion border, halfway between the vermillion border and the vestibule, and lateral to the midline. Four to six minor salivary glands are harvested and the wound sutured by primary closure with two or three interrupted resorbable sutures without overlapping the mucosal edges.
  • Complications are seen in less than 10%, partial loss of sensation of the lip being the most commonly reported due to injury to the labial branch of the mental nerve.
  • Immediate postoperative complications are pain, lip swelling and bruising of mucosa or skin. Sampling errors may occur.
The resulting hypoaesthesia may take over a year to resolve.
  • Lip biopsy is currently accepted as one of three minimum criteria in confirming Sjogren’s syndrome in the presence of focal lymphocytic sialadenitis with a focus score >1 focus/4 mm2 in labial salivary gland biopsy samples (Shiboski, Shiboski and Criswell, 2012).
Fine‐Needle Aspiration Biopsy
  • Fine‐needle aspiration biopsy (FNAB) provides a versatile technique in the initial diagnosis of lumps and tumour‐like masses in sites, such as the breast, thyroid gland, and the prostate gland.
The benefit of the technique is that FNAB may avoid the complications incurred during open biopsy at these sites.
  • Oral and paraoral lumps that could be investigated by FNAB include lumps suspected to be parotid adenomas to distinguish from chronic sialadenitis, palpable lymph nodes to exclude lymphomas, and swellings suspected of vascular origin to avoid bleeding complications.
Although FNAB is valuable in these circumstances, it is not as accurate as a tissue sample as architectural context is lost in a cytology preparation and it is not preferred for assessment of lesions accessible or considered safe to perform by a scalpel.
Punch Biopsy
  • Enables a small biopsy of oral mucosa of 3–6 mm diameter to be taken.
The technique is particularly useful for a palatal biopsy.
  • After administration of local anaesthesia the punch is twisted vertically to a depth of about 3 mm and the base is severed with surgical scissors or a scalpel. A suture may be required to close the biopsy site.
  • A punch is a useful adjunct to obtain normal mucosa for direct immunofluorescence studies to diagnose vesicular–bullous disorders.
  • Intact epithelium and connective tissue are critical in evaluation of a specimen for direct immunofluorescence studies.
Biopsy of a fresh intact vesicle or bulla is difficult as it ruptures rapidly during a biopsy procedure. Therefore, the site of biopsy for a vesicular–bullous disease should be adjacent to a bulla/ulcer (perilesional) where epithelium is intact.
  • The sample should be transported following quick freezing in liquid nitrogen or in the commercially available Michel’s medium.
  • Biopsy of solid bony lesions may also be obtained by a trephine instrument.
Brush Biopsy
  • A brush biopsy is designed to obtain complete transepithelial samples of mucosal lesions suspected of carcinoma or epithelial dysplasia.
It allows cytopathological examination to decide on the indication for a knife biopsy and is not an alternative to earlier referred sampling technique by incision biopsy.
  • The circular end of the brush is placed over the mucosa, rotated 8–10 times while maintaining firm pressure to allow the brush to penetrate the full thickness of the epithelium until pin‐point bleeding is apparent at the site.
  • The cellular material collected on the brush is transferred to a glass slide by smearing and then immersed in a fixative to avoid air drying.
  • Slides stained with the Papanicolaou method can be read by a cytopathologist to detect gross epithelial abnormalities (cellular atypia).
In the USA, the specimens are transferred to Oral CDx laboratories to obtain a computerised report on cellular atypia. A multicentre study in the USA reported good sensitivity of the technique (Sciubba, 1999).
Sentinel Node Biopsy
  • Sentinel node (SLN) biopsy facilitates the detection of lymph nodes potentially containing malignancy.
The first lymph node in a regional draining area that receives lymphatic flow from the tumour is designated the sentinel node.
  • During the procedure the SLN is identified using radioactive colloid and a blue dye. This node is excised and examined by microscopy using serial sections. Tumour negative SLN precludes the presence of metastasis in regional nodes.
This procedure aims to avoid unnecessary treatment to the clinically negative neck by identifying the patients with occult neck disease.
  • In a meta‐analysis evaluating the diagnostic reliability of sentinel lymph node biopsy in patients with squamous cell carcinoma of the oral cavity the overall sensitivity in 631 tumours included in the study was 94% (95% CI 89–98 %).
Showed that SLN biopsy is a valid diagnostic technique to correctly stage regional metastases in patients with head and neck squamous cell carcinoma.
  • An earlier review indicated 100% of oropharyngeal (n = 72), tumour sentinel lymph biopsy results correlated with subsequent neck dissections giving a negative predictive value of 100%.

Table 14.2 Selection of biopsy techniques appropriate for the condition and underlying rationale.

Condition Biopsy type Rationale Special considerations
Leukoplakia
Erythroplakia
Incisional
  • To exclude SCC
  • To exclude other conditions
  • To assess epithelial dysplasia
  • To stain for Candida
Representative sample.
Ulcerated red areas – a separate biopsy.
Persistent new growth or ulcer Incisional To exclude/confirm SCC Include normal marginal tissue
Sufficiently deep up to muscle.
Polyps, warts, mucoceles Excisional Treat by excision Any adjacent vital structures
Granulomas Incisional Diagnosis Sufficiently deep as granulomatous
areas are mostly deep seated.
Lumps on lip and palate FNA preferred Biopsy should be avoided to prevent spillage of tumour Refer to specialist Head and Neck Unit.
Pigmented macules Incisional or excisional Exclude melanoma If small may be excised.
Avoid vital structures.
Vesicular‐bullous Punch To determine intra‐or subepithelial
  • Perilesional tissue preferred.
  • Transport fresh or in Michel’s medium.

SCC, squamous cell carcinoma.

Image described by caption and surrounding text.

Figure 14.1 Standard biopsy kit.

Image described by caption.

Figure 14.2 (a) Suture passes through proposed biopsy site. (b) Outline of biopsy. (c) Biopsy freed from underlying tissue. (d) Suture placed close to biopsy site. (e) Biopsy site closed.

Chairside Diagnostic Tests for Mucosal Disease

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  • Adjuncts to conventional methods for the detection of oral cancer and precancer include:
    • Toluidine blue test.
    • Autofluorescence.
    • Chemiluminescence.
Toluidine Blue Test
  • The use of toluidine blue dye as a mouthwash or topical application has been investigated as an aid to the diagnosis of oral cancer and potentially malignant lesions.
The World Dental Federation (FDI) Commission supports the use of toluidine blue in appropriately experienced hands while urging further research on its clinical utility in primary care settings. Although 100% of squamous cell carcinomas are dye positive, close to 75% of oral potentially malignant disorders may stain and in addition many benign conditions also show vital staining.
  • With appropriate training, vital staining may assist in screening high‐risk subjects and in helping to define the site for biopsy.
  • For clinicians in primary care settings, specific training is required for correct application of the test and correct interpretation of the results.
Jan 22, 2018 | Posted by in General Dentistry | Comments Off on Procedures in Oral Medicine
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