VERRUCOUS CARCINOMA: CLINICAL FEATURES, HISTOPATHOLOGY AND TREATMENT
Author: Sanketh DS, MDS
INTRODUCTION & ETIOLOGY
Verrucous carcinoma is a low grade variant of oral squamous cell carcinoma, that is exophytic and warty. This lesion was first described by Ackerman in 1948, and is also called Ackerman’s tumor.
Unlike its cousin squamous cell carcinoma, verrucous carcinoma locally invades adjacent tissues, infrequently shows dysplasia and does not metastasize.
Verrucous carcinoma may comprise approximately 1% – 16% of oral squamous cell carcinomas. Smokeless tobacco, both chewing and snuff form have been significantly implicated in causing verrucous carcinoma. However, cases have also been reported in people with habits like smoking and alcohol and no identifiable risk factors. Human papilloma virus, types 6,11,16 and 18 have been isolated in sporadic cases, though its role in causing the lesion is debatable.
Verrucous carcinoma is commonly seen in elderly patients within the 60-70 age range predominantly in males. Most common oral sites are the buccal mucosa, mandibular vestibule, alveolar ridge and tongue, especially lateral borders. Other sites may include gingiva, palate and the floor of the mouth. It clinically appears as a thick white plaque that is exophytic, diffuse and papillary/warty. Though predominantly white, it may also manifest as a red or pink lesion or a mixed red-white lesion at times. When manifesting on the alveolar ridge or the mandible, verrucous carcinoma may get fixed to the underlying periosteum, subsequently invading the mandible. Verrucous carcinoma, if unattended to, may invade adjacent tissues like the muscle, bone and salivary glands. Patients may have enlarged cervical lymph nodes that are inflammatory in nature and do not represent nodal metastases.
Microscopic features of verrucous carcinoma may appear deceptively benign and may require careful screening. The epithelium is hyperplastic, and hyperkeratotic (usually parakeratosis), with the surface of the lesion having exophytic, verruciform projections that may be sharp or blunt. There may be depressions or clefts in the epithelium between surface projections, that are filled by parakeratin. This is referred to as parakeratin plugging. Epithelium shows no dysplasia and is well differentiated, though it may show dysplasia rarely.
A characteristic feature is the broad and bulbous rete ridges, that “push” into the underlying connective tissue.
An accurate diagnosis of verrucous carcinoma requires an adequate incisional biopsy which must include a part of the normal epithelium along with the lesional tissue.
Diagnosis of verrucous carcinoma is confirmed, when the broad rete ridges show an endophytic growth, i.e, the lesional rete ridges “push” into the connective tissue with an intact basement membrane, beyond the adjacent basement membrane of the normal epithelium. Care must be taken to screen for this feature, as another lesion called verrucous hyperplasia has similar features of verrucous carcinoma minus the endophytic growth pattern.
Verrucous carcinoma has to be surgically excised and excision need not be as extensive as a conventional squamous cell carcinoma.
Also,it is important for pathologists to screen the lesion thoroughly, to check for foci of conventional squamous cell carcinomas within a verrucous carcinoma. Not diagnosing foci of squamous cell carcinomas in a verrucous carcinoma may lead to a treatment failure and recurrence of squamous cell carcinoma. Hence, such lesions should be diagnosed and treated as conventional squamous cell carcinomas.
Radiotherapy is a strict no, as there have been reports of anaplastic, poorly differentiated carcinomas developing within lesions treated with the same. The overall prognosis is good and much better than conventional oral squamous cell carcinoma.
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OTHER (HACKDENTISTRY) PRACTICE/STUDY RESOURCES