Carcinoma of the lips is the most common malignant tumour of the oral cavity.1 In a large review of 1,252 patients, 96.7 percent were found in males and 95.6 percent of cases involved the lower lip.2 Prolonged exposure to sunlight and outdoor occupations are known major etiological factors for squamous cell carcinoma of the lips.3,4
CASE REPORT
A 42-year-old Hispanic male was referred by their general dentist to an oral and maxillofacial surgery office for evaluation of a left lower lip lesion that had been present for many months and had been gradually increasing in size. The lesion was painless but did bleed on occasion. The patient reported that he worked outdoors for over a decade without the use of any sunscreen. Patient denied any smoking or history of trauma to the area. The patient did drink on average three beers per week and was otherwise healthy. A clinical examination revealed a raised crusted oval shaped lesion of the lower left lip around 15x10mm (Figs. 1 & 2) and no palpable lymph nodes. A resection of the lesion and primary closure of the defect was performed under general anaesthesia (Fig. 3). The lateral border of the specimen (Fig. 4.) was tagged with a long nylon suture and was submitted in formalin for evaluation by an oral and maxillofacial pathologist. The pathology report came back with a diagnosis of well-differentiated squamous cell carcinoma with a positive medial resection margin, while the lateral and deep margins were negative. A photomicrograph of the lesion at low power (Fig. 5) exhibited a violation of the basement membrane and a down growth of broad rete pegs and islands of squamous epithelium.
A high power photomicrograph (Fig. 6) exhibited well-differentiated squamous epithelium, keratin pearl formation and an intense chronic inflammatory infiltrate. An additional resection was performed and completely clear margins were obtained. A head and neck MRI was taken post-operatively and came back negative for any lymph node involvement or tumour extension. The patient’s recovery and healing was uneventful (Fig. 7) and the patient follows up regularly with the office.
DISCUSSION
In addition to squamous cell carcinoma, the differential diagnosis of a lesion on the lower lip should also include keratoacanthoma, which is another similar lesion associated with sun exposure. Definitive diagnosis requires a surgical biopsy and histological examination. Squamous cell carcinomas of the lower lip that involve less than 40 percent of the total lower lip area may be treated with a full thickness V-shaped or shield excision with 5mm margins.5 Potential risks and complications of the procedure include post operative pain, haemorrhage, edema, ecchymosis, infection, nerve injury, scarring, recurrence and need for additional procedures. After the full thickness excision, the through and through defect is closed in layers beginning with the reapproximation of the muscular layer, dermis and subcutaneous layers, skin closure with careful attention to the vermillion border and the mucosal layer.6
Defects that are greater than 40 percent of the lower lip can be reconstructed using lip rotational flaps such as the Karapandzic or Abbe-Estlander flaps.7 Supra-omohyoid neck dissection is recommended for patients with palpable lymph nodes.8 Radiation therapy is another treatment modality to be considered.9 Prognosis for lower lip carcinomas is excellent with an only eight percent recurrence rate and a five-year survival rates of 95-100 percent.10
SUMMARY
Dentists are in a unique position to be one of the first health care professionals to diagnose squamous cell carcinoma of the lower lip, which is readily curable when diagnosed early. Due to its association with ultraviolet radiation, patients should be reminded to limit their direct sun exposure and regular sunscreen use is recommended.
Dr. Lin is an oral and maxillofacial surgeon with a private practice in Markham, Ontario. He also is a clinical instructor and Associate in Dentistry at the Division of Oral and Maxillofacial Surgery, Faculty of Dentistry, University of Toronto. Oral Health welcomes this original article.
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