CC
A 53-year-old male is referred to your office by his general dentist for evaluation of an intraoral lesion that was found during a routine dental examination.
HPI
The patient presents with an asymptomatic, corrugated white patch of the left buccal mucosa; he was not aware of the lesion until his general dentist detected it during a routine oral examination. The lesion has been present for an unknown duration. He denies any history of trauma, cheek biting (morsicatio buccarum), or chewing tobacco use. He denies any history of weight loss, fatigue, neck masses, or other constitutional symptoms.
PMHX/PSHX/medications/allergies/SH/FH
The patient’s history is significant for a 44 pack year history of smoking. He drinks three or four beers per week.
Examination
General. The patient is an male who appears his stated age. He is well nourished with no signs of cachexia.
HEENT. There is a 2.3-cm × 2.8-cm irregular, multifocal, superficial, soft, slightly elevated, heterogenous white plaque of the left buccal mucosa. The lesion is nonindurated, nonulcerated, and nonadherent to the underlying tissues. The lesion does not rub off with gauze and does not form bullae with firm pressure (negative Nikolsky sign). No Wickham striae (seen in lichen planus) are present, and the lesion does not diminish or disappear when stretched (seen in leukoedema). No other lesions or masses are noted in the oral cavity. He is partially edentulous with poor oral hygiene but no grossly carious teeth.
Neck. No submandibular or cervical lymphadenopathy is noted.
Imaging
Imaging for soft tissue lesions is based on the clinical presentation and differential diagnosis. This lesion is a superficial mucosal lesion that does not appear to invade underlying structures; therefore, no imaging studies are required.
Labs
No routine laboratory studies are necessary for workup of or before biopsy of a white lesion in an otherwise healthy patient.
Differential diagnosis
The differential diagnosis of a white lesion of the buccal mucosa that cannot be scraped off should include hyperkeratosis, frictional keratosis, morsicatio buccarum (chronic cheek biting), lichen planus, nicotine stomatitis, leukoedema, white sponge nevus, oral epithelial dysplasia, and squamous cell carcinoma (SCC).
Leukoplakia is a clinical term that simply describes a lesion as a white plaque; it is not a histologic diagnosis, and like various grades of mucosal dysplasia, is not predictive of malignant transformation to invasive carcinoma. Leukoplakia, applied as a provisional diagnosis at initial detection, is appropriate if no other differential diagnoses emerge as likely candidates. An incisional or excisional biopsy can rule out the many other well-established diagnoses that present as white plaques of the oral cavity. If histopathologic examination does not establish any of the other diagnoses listed, then leukoplakia transitions from being the clinical description to the diagnosis of exclusion. It is important to understand that leukoplakia cannot be considered the diagnosis of exclusion without a biopsy.
Biopsy
To rule out traumatic causes, it is reasonable to begin by identifying and eliminating possible etiologic factors and then waiting 2 to 3 weeks to reassess for resolution. Biopsy of a persistent white patch or plaque in the oral cavity is recommended to establish a formal diagnosis. Whether the biopsy is incisional or excisional depends on the size and character of the lesion. Typically, lesions smaller than 1 cm in size can be easily excised with primary closure of the surrounding mucosa. To avoid confounding future attempts at excision, an incisional biopsy, without violating the margin, is indicated for larger lesions or when malignancy is suspected.
In this patient, an incisional biopsy demonstrated moderate dysplasia, which has a 3% to 36% rate of malignant transformation. Definitive treatment included wide local excision with 5-mm margins followed by CO 2 laser ablation of the surrounding at-risk mucosa, and cadaveric dermal allograft of the defect followed by aggressive physiotherapy to preserve mandibular range of motion. Final histology revealed architectural and cytologic changes involving the full thickness of squamous epithelium, including the basal layer. Some of these include cellular polymorphism, enlarged nucleoli, nuclear hyperchromatism, increased nuclear-to-cytoplasmic ratio, mitotic figures, loss of polarity of basal cells, basaloid appearance of several cell layers, and irregular epithelial stratification. Despite full-thickness epithelial involvement, the integrity of the basement membrane was maintained in this specimen, and there was no evidence of epithelial invasion into the underlying submucosal connective tissue. Thus, a final diagnosis of severe dysplasia was made.
Assessment
The provisional clinical diagnosis was oral leukoplakia. The final histopathologic diagnosis was biopsy-proven severe dysplasia of the left buccal mucosa.
Treatment
The patient’s leukoplakia was amenable to excision ( Fig. 46.1 ) with CO 2 laser ablation of the surrounding at-risk buccal mucosa. The benefit of cold knife excision is that it is both diagnostic and therapeutic. (If carcinoma would have been detected in the specimen, the patient would have undergone a complete oral SCC workup.) Thermodestructive modalities such as laser treatment do not allow for histologic assessment, which may lead to missing a carcinoma within a leukoplakic lesion. In our case, an elliptical incision was made around the entire lesion, and the depth was taken down to the submucosa. Microscopic examination of the junction between the basement membrane and submucosa is necessary to rule out invasive carcinoma. Five millimeters of normal-appearing tissue surrounding the area was also included in the specimen. Histopathologic assessment of the leukoplakia revealed severe dysplasia, not extending to the specimen margins; this is a departure from the initial biopsy grade of “moderate.” The defect was covered with thin cadaveric dermal allograft, and jaw stretching physiotherapy was initiated on postoperative day 21. The patient demonstrated complete healing after surgery and was followed for surveillance with his surgeon and local dentist ( Fig. 46.1C ).
