Diagnosis of the Nature of Suspected Oral Lesions

By Silvio Abati and Alessandra Lissoni, Vita-Salute San Raffaele University – Milan

What Oral Cancer Is

Oral cancer is a disease that is, in most cases, fatal if not detected and treated in its early stages. The role of the dentist and dental hygienist is fundamental in preventing the disease and intercepting it at an early stage.

In its initial stages, oral cancer often causes no symptoms; at times, it may present as an area of burning or persistent pain. Local lesions can take various forms: white or red patches, areas of pathological growth, or persistent ulcerations. In the advanced stages, infiltration of the surrounding tissues causes pain and difficulty in chewing, swallowing, or changes in speech. More frequently, oral cancer is located on the lateral borders of the tongue and the floor of the mouth; less common sites are the retromolar trigone, gums, buccal mucosa, and palate.

Any lesion or pathological alteration of the oral mucosa that does not heal spontaneously within two weeks must be considered potentially malignant until proven otherwise by histopathological analysis. This concept forms the basis of the so-called “14-day rule” or “two-week rule,” which is recommended in clinical guidelines and referenced in the recommendations of the World Health Organization and other professional bodies. In all cases where spontaneous regression of lesions is not observed within two weeks, diagnostic investigation of the disease’s nature is required.

How Oral Cancer Is Diagnosed

In clinical practice, the diagnostic test most frequently required is the histopathological examination of the lesion (excisional biopsy) or a portion of the lesion (incisional biopsy) after surgical tissue sampling, allowing the pathologist to study the diseased tissue microscopically.

If there are evident local signs of malignancy, it is not appropriate to delay the planning and/or execution of the diagnostic biopsy. Signs of malignancy include persistence for more than two months, rapid growth, variegated coloring with erythroplasia, ulceration, induration, fixation to deep tissues, and bleeding after minor trauma.

The use of auxiliary methods to identify pre-tumoral or tumoral risk lesions improves the detection of areas and lesions of the oral mucosa that require monitoring, referral to a specialist, or biopsy sampling.

Among these, one of the most recent methods is tissue autofluorescence detection (OFI). Dysplastic and neoplastic alterations of the oral mucosa lead to a decrease or disappearance of the normal tissue’s fluorescent image when excited by blue-violet light, typically produced using a polymerization lamp. The mucosal lesion areas thus appear dark and well-defined (Figures 1 and 2) against the background of the bright green fluorescence emitted by healthy oral tissues. This enables biopsy sampling from a significant portion of the lesion.

Oral Tissue Biopsy

Biopsy is defined as the removal of living tissue for diagnostic purposes. In the oral cavity, the biopsy is performed on an outpatient basis in a relatively simple manner using: local anesthetic and corresponding syringes with fine needles, a scalpel with a BP15 blade, anatomical tissue forceps, surgical forceps, scissors, a needle holder (typically microsurgical, e.g., Castroviejo), and 4-0 or 5-0 suture thread.

Analgesia is achieved through loco-regional anesthesia or, more commonly, by infiltrating small amounts of anesthetic at several points around and beneath the lesion, taking care not to pass the needle through the lesion itself to avoid potential deep transport of neoplastic cells and not to inject directly into diseased tissue to prevent artifacts. The tissue to be removed can be held with atraumatic forceps or lifted using suture thread.

The biopsy should include a portion of healthy tissue surrounding the lesion; the incision, usually diamond-shaped, must reach sufficient depth into the connective tissue to allow study of the lamina propria, since diagnostic changes may develop within it. In cases of suspected malignant lesions, suturing is generally avoided, except to ensure adequate hemostasis.

After the procedure, the surgical wound typically heals within about a week, generally without painful or infectious local complications.

Performing the surgical procedure for biopsy examination of the oral mucosa correctly — with proper indications, techniques, and outcomes — may, however, require clinical expertise and experience not always available in a general dental practice. Therefore, referral to a specialist may be necessary.