MALIGNANT NEOPLASMS

Squamous cell carcinoma

Squamous cell carcinoma (SCC) is a malignant neoplasm of epithelium and is the most frequent malignant tumor encountered intraorally. The lips are also considered as intraoral sites. The etiology of malignancies in general is considered multifactorial and based in the so-called co-carcinogenic theory, where intrinsic and extrinsic factors acting simultaneously or in succession are considered responsible for the development of malignant neoplasms. Among the intrinsic factors often mentioned are immunity, nutrition, age, heredity and DNA composition (proto-oncogenes and oncogenes). Contributing extrinsic factors associated to oral SCC include: tobacco use, either smoked or chewed in its various forms, actinic radiation, viral infections, especially with human papilloma viruses (HPV), Epstein-Barr virus and HIV, lichen planus, chronic infections such as syphilis and candidiasis, chronic irritation and finally alcohol intake. Of all those factors, the use of tobacco and oral cancer has been firmly demonstrated by a barrage of statistical studies. Actinic radiation has been shown to be associated as a causative agent for cancer of the lips especially in individuals of very light complexion. The participation of viruses (especially HPV), in at least oral cancers, has not been definitely ascertained, but there is no doubt of their participation as co-factors in the production of uterine cervical cancer and also in anal cancer in HIV patients. The Epstein-Barr virus is considered responsible for the production of the Burkitt's lymphoma of the jaws in children and recently, the herpes simplex 8 virus has been considered the cause of Kaposi's sarcoma. Several reports have documented the pre-cancerous potential of lichen planus. A recent follow-up study on 665 patients with lichen planus by Silverman and co-workers report a rate of malignant transformation of 3.2%. Another study from the United Kingdom by Barnard et al reports a 3.7% malignant transformation rate on 241 patients with lichen planus. Thirty percent of patients who develop syphilitic glossitis have been reported in the past as developing SCC of the tongue. Candidal infection, chronic irritation and alcohol abuse are still mentioned, but their role as co-carcinogenic agents is still to be proven.

SCC comprises 90% of all intraoral malignancies. Oral SCC is found with greater frequency after the age of 50 years and its sex predilection varies according to its location. According to a study by the National Cancer Institute for the period from 1983 to 1993, the most frequently affected intraoral site is the tongue followed by the lips, floor of the mouth and gingiva, in that order. Gingival SCC is found with equal frequency in both sexes. The mandibular gingiva is affected in 60% of cases (maxillary gingiva 40%). At time of diagnosis 34% of cases are localized but in the remaining 66% metastatic lesions are already present. Fifty percent of the gingival SCC are classified histologically as corresponding to Broders'index Grade 2 or higher, which means moderately to poorly differentiated. The less differentiation, the more aggressive and invasive the SCC. The five years survival rate for gingival SCC is 26%.

Clinically, gingival SCC tends to develop with greater frequency in the molar premolar area and its appearance can range from an area of leukoplakia to a frankly exophitic mass. Other clinical presentations include mixed erythematous and leukoplakic areas, superficial ulcer or deep ulcer with elevated borders, pyogenic granuloma-like growth and poorly defined fungoid mass. Those gingival SCC which are associated with tobacco chewing, snuff or quid use tend to be very superficially extended and have a verrucoid appearance. These latter SCC tend to be superficially invasive and their prognosis is better than for the other clinical varieties. Teeth mobility will be present in those teeth adjacent to the tumor when the gingival SCC invades bone and periodontal ligament.

The proper evaluation of a suspected gingival SCC, in addition to clinical inspection, includes a radiographic studies and a biopsy. The treatment is in the hands of the oncology team. Surgery, radiation, chemotherapy or a combination of either are used and the choice depends on location, size of the tumor, bone involvement, presence or absence of metastasis (either distant or to regional lymph nodes), histologic degree of differentiation, age and nutritional state of the patient.

Figure 20. This a gingival squamous cell carcinoma. Note the fungoid, white and red surface. Also note the marked gingival retraction at the level of both molars. This patient had a bad brushing habit but the tooth brush trauma can not be held responsible for the development of this malignant neoplasm.	Figure 21. This 34 year-old woman had what clinically resembles a pyogenic granuloma. The interdental papilla is markedly enlarged and it has a granular. erythematous surface. The lesion was excised in toto and the biopsy showed it to be an early squamous cell carcinoma (Courtesy of Dr. Sol Silverman Jr. UCSF)
Figure 22. This 64 year-old man was a heavy smoker. The red and white lesion on the gingiva of tooth #8 is a squamous cell carcinoma. The patient had a extremely poor oral hygiene and relates that this lesion has been growing steadily for the last 2 months.	Figure 23. This an example of verrucous squamous cell carcinoma in a 50 year-old woman who was a tobacco chewer and held the snuff in the anterior vestibular area. Note the extent of the lesion involving gingiva and vestibular and lip mucosas. This is an exophitic white and red lesion.
Figure 24. This 73 year-old woman had the habit of reverse smoking. Note the gigantic squamous cell carcinoma involving the anterior vestibule, alveolar ridge and extending into the floor of the mouth. There was marked teeth mobility and diffuse pain.	Figure 25. This 71 year-old woman had a long history of intraoral erosive lichen planus. The lesion observed at the level of the posterior lingual gingiva and the retromolar pad was diagnosed histologically as a grade I squamous cell carcinoma. According to her dermatologist she had had recurrences of her lichen planus in that area.