What is the significance of indentations at the lateral border of the tongue?

Indentations at the Lateral Border of Tongue

Indentations at the lateral border of the tongue (also called scalloped tongue or crenated tongue) are typically benign impressions caused by chronic pressure from adjacent teeth, but require urgent evaluation to exclude underlying pathology, particularly when associated with white lesions or other concerning features.

Clinical Significance and Differential Diagnosis

Benign Causes (Most Common)

• Tooth impressions represent the most common etiology, resulting from chronic tongue pressure against the dentition, often associated with macroglossia, tongue thrust habits, or parafunctional activities 1
• These indentations are frequently observed in patients with mouth breathing or tongue-thrust habits, which create sustained pressure patterns against the lateral dental surfaces 2
• The presence of tooth impressions alongside other findings (such as geographic tongue or fissured tongue) suggests a benign anatomical variant rather than pathological process 2

Critical Red Flags Requiring Urgent Evaluation

• White borders or patches at the lateral tongue border with indentations mandate immediate biopsy within 2 weeks, as the lateral tongue is a high-risk site for oral squamous cell carcinoma 3
• The American Academy of Oral Medicine defines oral leukoplakia as a predominantly white patch that cannot be wiped away and is not characterized as any other definable disorder - this requires tissue diagnosis 3
• Non-homogeneous white lesions on the lateral tongue carry significantly higher malignant transformation risk than homogeneous types and require urgent biopsy 3

Mandatory Diagnostic Algorithm

Immediate Assessment

• Attempt to scrape any white areas - if the lesion cannot be removed, consider biopsy for leukoplakia, melanoma, or carcinoma 4
• Document lesion characteristics: size, exact location, homogeneous vs. non-homogeneous appearance, and obtain photographic evidence if possible 3
• Assess for high-risk features: age >40 years, tobacco use, alcohol abuse, ulceration, induration, firmness on palpation, or cervical lymphadenopathy 3, 4

Biopsy Indications (Within 2 Weeks)

• Any persistent white lesion on the lateral tongue, particularly if non-homogeneous or present >2-3 weeks 3
• The British Journal of Dermatology recommends performing incisional biopsy of any persistent lateral tongue white lesion given the malignant potential 3
• Do not observe without tissue diagnosis given the lateral tongue location - this is a high-risk site for oral squamous cell carcinoma 3

Pre-Biopsy Laboratory Evaluation

• Obtain full blood count to rule out hematologic disorders such as leukemia or anemia 3
• Check coagulation studies to ensure no surgical contraindications 3
• Measure fasting blood glucose to assess risk of invasive fungal infections that can mimic malignancy 3

Management Based on Clinical Presentation

Benign Indentations Without White Lesions

• Reassurance is appropriate when indentations are isolated findings without associated white patches, ulceration, or other concerning features 1, 2
• Address contributing factors: counsel on cessation of tongue-thrust habits, evaluate for sleep-disordered breathing if mouth breathing is present 2
• No treatment or biopsy required for simple tooth impressions in the absence of other pathological features 2

Indentations WITH White Borders or Lesions

• Refer to oral medicine specialist or oral surgeon for biopsy within 2 weeks if unable to perform 3, 4
• Do not delay biopsy for empiric antifungal treatment - if candidiasis is suspected, attempt to scrape the lesion first; persistent lesions after 2 weeks of antifungal therapy require biopsy 3
• Counsel on tobacco and alcohol cessation if applicable, as these are synergistic risk factors for squamous cell carcinoma 4

Common Pitfalls to Avoid

• Never assume a white lateral tongue lesion is benign without histologic confirmation - the lateral tongue is a high-risk site for oral squamous cell carcinoma 3
• Do not rely on clinical appearance alone to distinguish between oral leukoplakia, lichen planus, and early malignancy - histopathology is essential 3
• Avoid observing non-homogeneous lesions or delaying referral beyond 2 weeks for any persistent white lesion on the lateral tongue 3, 4
• Do not confuse benign tooth impressions with pathological conditions - the key distinguishing feature is the presence or absence of mucosal changes (white patches, ulceration, induration) beyond simple indentations 1, 2