Verrucous carcinoma: a possible viral pathogenesis

Carcinoma Cuniculatum of the Larynx

Carcinoma cuniculatum (CC) is a rare clinicopathologic variant of squamous cell carcinoma. Histologically, it is characterized by invasive growth of bland, acanthotic, and keratinizing squamous epithelium that forms multiple rabbit burrow-like, keratin-filled crypts and sinuses. We present a 51-year-old male smoker with CC of the left vocal cord. The tumor was staged T1a and the patient was disease-free 12 months after surgery. To our knowledge, this is the fourth case of CC of the larynx reported in the English literature and the first, due to its early diagnosis, where radical surgery was not performed. We highlight the necessity for awareness of this entity and coordination between otolaryngologists, radiologists, and pathologists for early diagnosis and organ-sparing surgical treatment.

Comprehensive analysis of human papillomavirus prevalence and the potential role of low-risk types in verrucous carcinoma

The role of human papillomavirus (HPV) infections in the development of verrucous carcinoma, a well-differentiated variant of squamous cell carcinoma with difficult differential diagnosis, is controversial in the literature. In this study, we analysed verrucous carcinoma from different origins for the presence and activity of a broad spectrum of HPV types, and carefully reviewed the histopathological features. A random series of 27 formalin-fixed, paraffin-embedded specimens of verrucous carcinoma was taken, representing the head and neck region (n=6), anogenital area (n=16) and extragenital skin region (n=5). After review of the histological slides, all samples were subjected to different polymerase chain reaction-based HPV detection techniques, together detecting a total of 83 HPV types, including both mucosal and cutaneous types. Histological revision was carefully performed. Lesions with keratinised papillae, blunt stromal invaginations and minimal cytological atypia were considered verrucous carcinoma. Condylomatous lesions with viral changes were defined as giant condyloma. Verrucous lesions that did not meet those criteria were classified as verrucous hyperplasia. Tumours with stromal infiltration were considered as invasive squamous cell carcinoma. Histological revision revealed that 13 out of 27 cases were verrucous carcinoma (one showing a double infection with HPV 35 and 45), 5 invasive squamous cell carcinomas, 5 verrucous hyperplasia (one with a double infection with HPV 4 and 8), 1 pseudoepitheliomatous hyperplasia and 3 giant condylomas. All three giant condylomas were low-risk HPV positive (HPV 6 and 11) and showed active mRNA transcription. None of the HPV-positive samples tested positive for diffuse p16(INK4A) staining. In conclusion, our results do not support a causal role of HPV in the development of verrucous carcinoma. Testing for LR-HPV, particularly HPV 6 and 11, may help in the differential diagnosis of lesions suspicious of verrucous carcinoma as those testing positive for LR-HPV most likely represent giant condylomas.

Oral verrucous carcinoma mimicking a chronic candidiasis: a case report

Verrucous carcinoma has a special propensity to mimic benign lesions of the oral cavity. A case of the oral verrucous carcinoma in maxillary alveolar ridge, extending to buccal vestibule, cheek, and labial mucosa, which was diagnosed and initially treated as chronic candidiasis, is presented. Clinical, histopathological, and therapeutic considerations related to diagnosis of the verrucous carcinoma in the oral cavity are discussed.

Oral squamous cell carcinoma versus oral verrucous carcinoma: an approach to cellular proliferation and negative relation to human papillomavirus (HPV)

Human papillomavirus (HPV) has been cited as a possible initiating agent in the pathogenesis of oral cancer. However, the literature tends to be both controversial and inconclusive about the prevalence of HPV and its potential for proliferation in oral squamous cell carcinoma (SCC). The aim of this study was to investigate the cellular proliferation and the presence of HPV in SCC and verrucous carcinoma (VC). Forty-seven samples of SCC were selected and divided into three groups: 39 SCC, 8 VC, and 9 of normal mucosa (control-CT). Quantitative analyses of all groups showed a greater expression of PCNA, followed by Ki-67 and cyclin B1. A significant difference was observed in cyclin B1 expression in the SCC group compared with VC. PCNA, Ki-67, and cyclin B1 were statistically significant when comparing the SCC and CT groups. However, when SCC and VC were compared, there was no difference in Ki-67 expression. Our results showed that only cyclin B1 had an association with histological grade, and that poorly differentiated tumors presented a higher expression of cyclin B1. Therefore, considerable differences in the cellular proliferation between SCC and VC were observed, and no correlation with HPV was established, since all samples were negative for HPV.

Verrucous carcinoma of the oral cavity: a clinico-pathologic appraisal of 133 cases in Indians

INTRODUCTION

Verrucous carcinoma (VC), a rare variant of squamous cell carcinoma is an established entity with distinctive morphology and specific clinical behavior. To date, only a small series of head and neck verrucous carcinomas have been reported in the literature.

MATERIALS AND METHODS

The present study evaluated 133 cases of verrucous carcinoma for the age, sex, site of involvement, duration of disease at the time of diagnosis, associated habits and common presenting symptoms, presence of other mucosal lesions, recurrence, and the histopathology.

RESULTS AND DISCUSSION

Verrucous carcinoma accounted for 16.08% among oral squamous cell carcinoma compared to 2-12% reported in the literature. VC was more common in males with greater predilection to buccal mucosa due to widespread use of tobacco chewing in Indian scenario. Age distribution was lower as compared to other studies with prominence in the fifth decade. Mandibular involvement was more frequent as compared to those in literature.

CONCLUSION

Development of recurrence following radiotherapy in few cases supports anaplastic changes by radiotherapy.

Aggressive verrucous carcinoma of the paranasal sinuses invading the orbit: case report and literature review

INTRODUCTION

Verrucous carcinoma is a variant of well differentiated squamous cell carcinoma characterised by an exophytic, warty growth which is slowly but locally invasive and which can cause extensive local destruction if left untreated.

CASE REPORT

We report the first known case of veruccous carcinoma of the paranasal sinuses with rapid orbital invasion. A 58-year-old man presented with right-sided nasal obstruction, a huge right intranasal lesion, intractable dacryocystitis and cutaneous involvement of the nasolacrimal sac region. The tumour was partially removed using an endoscopic transnasal approach. Post-operatively, and while waiting for the histological result, the patient developed signs of rapid invasion of the orbit, with uniocular visual acuity deficit. He underwent combined radiochemotherapy, with a moderate response.

CONCLUSION

Knowledge of the potentially aggressive nature of verrucous carcinoma may be helpful in early management of intraorbital invasion and salvaging of the eye.

Carcinoma cuniculatum of the larynx: a rare clinicopathological entity

Objective:

Carcinoma cuniculatum is a rare variant of low-grade squamous cell carcinoma. We report the second case of carcinoma cuniculatum of the larynx in the literature.

Method:

Case report and review of the world literature concerning carcinoma cuniculatum of the larynx and upper aerodigestive tract.

Results:

A histologically proven carcinoma cuniculatum of the larynx is reported in a 72-year-old man. The patient underwent a supracricoid laryngectomy with crico-hyoidopexy, and was free of disease at 70 months after surgery. We emphasise the clinical presentation, histology and therapeutic approach of this rare tumour.

Conclusion:

To our knowledge this is the second report in the world literature of carcinoma cuniculatum of the larynx. Carcinoma cuniculatum of the larynx must be considered as a distinct ‘clinicopathological entity’ and close cooperation between the clinician and the pathologist is essential for the correct diagnosis of these tumour as regards to the correct classification and therapy.

Oral verrucous carcinoma: a retrospective study in São Paulo Region, Brazil

Oral verrucous carcinoma (OVC) is a rare variant of squamous cell carcinoma with a characteristic morphology and specific behavior. To date, few studies are available focusing the prevalence and clinicopathologic features of the oral verrucous carcinoma in Brazilian population. A total of 3,500 primary oral well-differentiated squamous cell carcinoma surgically excised in the A.C. Camargo Cancer Hospital and Amaral Carvalho Cancer Hospital, Brazil, from 1980 to 2000 were retrospectively reviewed. Twenty cases of verrucous carcinomas were identified, most of them occurring in older male with age above the sixth decade, the sites frequently affected being the lower lip and the hard palate. Microscopically, the tumor showed a heavily keratinized lesion with compressive invasion pattern, little atypia, and free surgical margins. The local recurrence was verified in 38.5% of the patients with oral verrucous carcinoma; however, regional recurrence and distant metastasis were not verified. The results suggest that, although it is less frequent and with excellent prognosis, the verrucous carcinoma presents a potential for local recurrence that should be considered during the surgical planning of this neoplasm in the oral cavity.

Oral proliferative verrucous leukoplakia (PVL); open trial of surgery compared with combined therapy using surgery and methisoprinol in papillomavirus-related PVL

Proliferative verrucous leukoplakia (PVL) is a unique oral white lesion in which human papillomavirus (HPV) may play a role. PVL behaves far more aggressively than other forms of leukoplakia with a high rate of recurrence after surgical excision, and relentless progression to verrucous hyperplasia and to verrucous or squamous cell carcinomas. The treatment of PVL is usually by surgery, but there is often early recurrence. This study was an open trial of surgery in 25 patients with oral HPV-positive PVL, compared with combined therapy using surgery and methisoprinol in another group of 25 patients with oral PVL. Six months postoperatively there was a significant difference, with 18 recurrences in the patients treated by surgery alone compared to only two recurrences in the patients treated also with methisoprinol (isoprinosine or inosine pranobex), a synthetic agent with immunomodulatory properties and some antiviral activity against HPV. Eighteen months postoperatively there were no further recurrences in the patients treated by surgery alone but another two recurrences in the patients treated with methisoprinol. Overall, by 18 months follow-up, there were 18 recurrences in the group treated by surgery alone, compared with four in those also receiving methisoprinol. The use of this antiviral agent appeared to offer a significant enhancement to the surgical management of PVL.

A high frequency of allelic loss in oral verrucous lesions may explain malignant risk

Verrucous carcinoma (VC), a variant of squamous cell carcinoma (SCC), is distinct from SCC in morphology and behavior. The underlying genetic changes involved in the development of VC and its precursor verrucous hyperplasia (VH) are unknown. This study determined whether chromosomal regions frequently lost during the development of SCC are also lost in the VH/VC variant. Twenty-five VH and 17 VC were analyzed for loss of heterozygosity (LOH) at 19 loci on 7 chromosome arms using microsatellite analysis. These data were compared with those from 47 reactive hyperplasias, 92 dysplasias (54 low- and 38 high-grade), and 41 SCCS: The results showed that VC/VH shared many of the losses present in dysplasia/SCC but differed in two aspects. First, VC/VH showed early acquisition of loss, compared with a gradual accumulation of losses from dysplasias to SCC. The LOH pattern of VH was similar to that of high-grade dysplasia and sharply different from reactive hyperplasia. The loss in VH often involved multiple arms (in 60% of VH vs 0% of reactive lesions). Only a marginal elevation of loss was observed at 9p (p = 0.06) and 4q (p = 0.05) from VH to VC because of the high degree of loss already present in VH. Second, a strikingly lower frequency of loss at 17p was noted in VH/VC compared with dysplasia/SCC and may indicate human papillomavirus (HPV) involvement. The finding of high-risk LOH profiles in VH may partly account for the high-progression risk seen for VH and also has potentially important clinical implications. The difficult pathological diagnosis of VH/VC from reactive hyperplasia frequently requires repeated biopsies and results in delay in diagnosis and significantly increased mortality/morbidity. Microsatellite analysis might facilitate this differential diagnosis.

Oral verrucous carcinoma. Incidence in two US populations

Much is known about the clinical appearance, biological behavior, and treatment of verrucous carcinoma of the oral cavity. However, the epidemiologic characteristics are completely unknown. This cancer is considered to be rare in Western cultures because it is not common in oral pathology biopsy services, but there is no epidemiologic evidence for this belief. To provide this evidence, 2 population-based incidence investigations were carried out, one in Rochester, Minn., and the other in the state of West Virginia. The results were as follows: the age-adjusted average annual incidence rate for oral verrucous carcinoma among Rochester residents was 0.1/100,000 person-years (0.2 for males, 0.0 for females), whereas the incidence rate for all intraoral carcinomas was 3.6/100,000 person-years (5.4 for males, 2.1 for females). Among men over 64 years of age, the incidence rate for verrucous carcinoma was increased to 3.2/100,000 person-years. Verrucous carcinoma was among the least common of the oral carcinomas in this population, representing only 3% of the total. The age-adjusted incidence rate for oral and pharyngeal verrucous carcinoma among West Virginia residents was somewhat greater, 0.3/100,000 person-years, and showed an even gender predilection (0.28 for males, 0.29 for females). The incidence rate for all oral/pharyngeal cancers in West Virginia was 8.8/100,000 person-years (13.4 for males, 5.7 for females), which was below the US average. The conclusion is that oral verrucous carcinoma is a rare tumor of older people, diagnosed in only 1 to 3 of every 1,000,000 persons each year.

Dental factors in the genesis of squamous cell carcinoma of the oral cavity

This study investigated the role of dental factors in the genesis of squamous cell carcinomas of the oral cavity. 99 newly diagnosed patients with advanced head and neck cancer were evaluated for potential demographic, dental and prosthetic risk factors. Patients with extra-oral malignancies were used as controls in the analysis of dental factors in patients with intra-oral cancers. We performed multiple comparisons of these factors against the primary tumour sites. An analysis of dental and prosthetic factors and patients with intra-oral versus extra-oral tumours revealed no significant differences. However, all 28 intra-oral malignancies arose in areas in contact with teeth and/or appliances. For example, all 10 oral tongue lesions arose on the lateral borders and all six floor of (drop) mouth primary tumours developed at the flange extension of a lower denture. Patients with partial or full dentures had significantly lower node (N) scores than patients without a prosthesis. Although this paper suggests a relationship between dental factors and the genesis of oral squamous cell malignancies, a larger prospective study would be required to achieve definitive data. Patients at risk should be followed carefully for the development of chronic irritation from teeth and appliances.

Human papillomavirus in oral premalignant lesions

The aetiology of oral premalignant lesions is generally accepted to be multifactorial. Tobacco and alcohol are established as important cofactors in malignant development in the oral cavity, but in addition microorganisms, such as human papillomavirus (HPV), have gained much interest over the past decade. For many years, HPV has been accepted as an important cofactor in the development of cervical cancer, originating from a mucous membrane with similarities to the oral mucosa. 49 patients with oral premalignant lesions and 20 control patients with normal oral mucosa and no history of HPV infection were examined for the presence of HPV by immune histochemical staining using the peroxidase anti-peroxidase technique (PAP), DNA-DNA in situ hybridisation (ISH), and polymerase chain reaction (PCR) analysed by Southern blot hybridisation with an HPV 16 specific probe. The investigations revealed that HPV was found in 62.5% of the verrucous leucoplakias, 50.0% of the erythroplakias, 45.5% of the homogeneous leucoplakias, 33.3% of erythroleucoplakias and in 12.5% of the nodular leucoplakias. An overall HPV detection rate in the examined premalignant lesions was 40.8% and no patients in the control sample were positive. Concerning oral cancer development, it seems likely that HPV may be a cofactor, as 100% of patients who developed oral cancers within 4-12 years were all positive for HPV, one being positive for HPV 16.

Verrucous squamous cell carcinoma of the larynx: diagnostic and therapeutic considerations

The clinical findings, histopathology, management and outcome of 31 patients with verrucous squamous cell carcinoma of the larynx (VSCC) are discussed. Laryngeal VSCC is a rare, highly differentiated variant of SCC and has specific morphological features and clinical behavior. A close liaison between the laryngologist and pathologist is needed to formulate a correct diagnosis, because this tumor appears to be malignant clinically and histologically benign. A low-power magnification of multiple large specimens, including the deep margins of the lesion, is required in order to differentiate VSCC from keratosis, verruca vulgaris or SCC with verrucous appearance, and to detect underlying microscopic foci of invasive SCC within or adjacent to a verrucous carcinoma. Long-lasting hoarseness was the most common symptom as the glottic region was the most common site of VSCC. Presumed clinically positive N1 lymph nodes were observed in the necks of 7 patients, but none had metastatic disease on histopathological study. Surgery alone was the most effective form of treatment, as it allowed a good outcome of all treated patients. Surgery plus radiotherapy was associated with an early recurrence and a poor outcome in 2 of 7 patients treated. The generally "benign" behavior of VSCC allows for conservative surgery, with complete endoscopic resection using the carbon dioxide laser representing a more conservative surgical approach. Neck dissection is not indicated due to the non-metastatic behavior of this tumor.

Verrucous carcinoma (epithelioma cuniculatum) plantare

A case of plantar verrucous carcinoma is described. The lesion was treated as an ischaemic ulcer before the true nature was recognised. Prior to the diagnosis the patient had a femoro-popliteal arterial bypass graft performed. An amputation was undertaken once the diagnosis was established.

Comparison of oral carcinomas in smokeless tobacco users and nonusers

Biopsy reports of squamous cell carcinoma (SCC) and verrucous carcinoma (VC) were retrospectively evaluated to determine the prevalence of smokeless tobacco (ST) use and to ascertain if any clinical or histologic differences existed when comparing ST users with nonusers. Of the 874 SCC cases, 12 patients (1.4%) were ST users as compared with 7.7% (10 of 129) of the VC patients. The carcinomas in ST users, either SCC or VC, were diagnosed at a later age and were more likely to occur in the buccal mucosa/vestibule area. The SCCs in ST users were more often histologically well differentiated. Because of the anatomic site predilection, it appears probable that ST use is a causative factor in the development of some cases of oral carcinoma.

Pathogenesis of oral submucous fibrosis. Relationship to risk factors associated with oral cancer

Oral submucous fibrosis (OSF) is a chronic disease of the oral mucosa characterized by inflammation and a progressive fibrosis of the lamina propria and deeper connective tissues. It is a condition predominantly seen among people of Indian origin, and an epidemiologic survey done a decade ago showed no less than 250,000 cases in India, a figure that must have increased sharply. OSF is a condition with a high risk of malignant transformation; to date, no conclusive etiologic agent has been identified, although plenty of data have been generated on various aspects of the disease. These include genetic, carcinogenic, immunologic, viral, nutritional, and autoimmune possibilities, all of which also have been implicated in the development of oral cancer. This article reviews existing evidence on the pathogenesis of OSF and its relation to oral cancer and suggests a possible multifactorial model to explain the disease process.

Viruses and chronic disorders involving the human oral mucosa

Viruses have been implicated in the etiology of several chronic disorders of the oral mucosa. Most of these associations have been with DNA viruses, particularly certain herpesviruses, which are associated, for example, with some cases of erythema multiforme and with hairy leukoplakia. Papillomaviruses are associated with various papillomatous lesions, focal epithelial hyperplasia, and possibly with some carcinomas. Viruses may possibly be associated with recurrent aphthae, Behçet's syndrome, and some dermatoses. The literature concerning these possible associations is reviewed. However, much more research needs to be done before the full story of viral associations with oral mucosal disorders can be written.

Oral cancer

In the U.S. oral cancer accounts for 2.1% of all cancers and 1% of cancer deaths. Two to three times as many males as females are affected. Blacks have more intra-oral cancer than whites, and their incidence and mortality rates have increased in recent years. The etiologic process very likely involves several factors. The major etiologic agents are tobacco (all types) and alcoholic beverages. Herpes simplex virus, human papilloma virus, and Candida have been implicated. Host factors include poor state of dentition, nutritional aberrations, cirrhosis of liver, lichen planus, and immunologic impairmant. Cellular changes include amplification of some oncogenes, alterations in antigen expression, production of gamma-glutamyl transpeptidase, and disturbance of keratin and involucrin production. Experimentally, cancer is readily produced on the hamster cheek pouch and rat oral mucosa. Unlike oral cancer in humans, most experimental lesions are exophytic, and they rarely metastasize.

Human papilloma virus in erosive oral lichen planus

Several types of human papilloma viruses (HPV) have been associated with benign and malignant squamous cell tumours of mucosal epithelium. To identify HPV in erosive oral lichen planus (OLPe), considered as a premalignant lesion, tissues from 20 patients were examined by Southern blot hybridization with 32P-labeled HPV DNA probes. Type 11 was found in 6 of the lesions while HPV types 6, 16 and 18 were not detected in any of the tissues examined. Using a type-specific polymerase chain reaction (PCR) assay for HPV-6, 11, 16 and 18, HPV-11 was detected in 8 of the samples (all of those positive by Southern blot), and, in addition, HPV-6 was found in 5 samples and HPV-16 in 3 samples. Overall, by the more sensitive PCR assay, 65% of samples were positive for HPV DNA. The finding of HPV DNA in many of the samples using two different techniques indicates a high prevalence of HPV in the OLPe afflicted oral mucosa. However, the role of HPV in the pathogenesis of OLPe has yet to be determined.

Morphologic and immunohistochemical evidence of human papillomavirus capsid antigen in smokeless tobacco keratoses from juveniles and adults

Seventy-seven tissue samples from patients with either degree I, II, or III smokeless tobacco keratoses were examined. The tissues were evaluated for the presence of human papillomavirus (HPV) antigen by immunocytochemical staining. Capsid antigen could be identified in sixteen cases (20.78%). This investigation further supports the concept that smokeless tobacco-associated leukoplakias can be correlated with HPV infection.

Colposcopic evaluation of men with genital warts

Colposcopy, which is the examination of the female genital tract that generally is performed after the application of acetic acid, has been an effective tool in the diagnosis of genital warts (condyloma acuminatum) in women for years. With the help of colposcopy, both microscopic and flat warts that cannot be visualized with traditional, noncolposcopic methods can be seen and, hence, treated. Recently, studies reported in the gynecologic and urologic literature have evaluated the usefulness of colposcopy in male patients. We present a patient whose genital warts were recalcitrant to treatment. When examined with colposcopy he was noted to have multiple additional areas of involvement. In view of the neoplastic potential of the human papillomavirus, the ease with which it is transmitted sexually, and the difficulty in discerning certain kinds of warts without colposcopy, we believe colposcopic examination should be routine in all men with genital warts and in those whose sexual partners have tested positive for human papillomavirus.

Papillomaviruses: the current status in relation to oral disease

Human papillomaviruses of different types are associated with a variety of benign oral lesions and may be associated with some premalignant and malignant oral lesions. However, since it is now clear that a variant of human papillomavirus 16 is harbored by normal oral mucosa, as well as by premalignant and malignant lesions, such associations may not necessarily always be causal. The rapid progress of recent research in this field is reviewed, with particular reference to oral disease, and the current status is discussed.

A papillary-verrucous lesion in the gingiva, developing into squamous cell carcinoma

This report will focus attention on the diagnostic and therapeutic difficulties involved in a patient who presented with a gingival papillary-verrucous lesion, which subsequently developed into a squamous cell carcinoma.

Human papillomavirus type 2 DNA in oral verrucous carcinoma

Tissues from patients with oral verrucous carcinoma were examined for the presence of human papillomavirus (HPV). The tissues were stained for the presence of the type common papillomavirus antigen by immunohistochemical staining and the presence of HPV DNA was determined by in situ hybridization with biotin-labelled HPV DNA probes. Seventeen tissue specimens were obtained from 9 patients, and included pre-malignant lesions and primary and recurrent tumors. One pre-malignant lesion was positive for papillomavirus structural antigen. This lesion and lesions from 2 other patients hybridized at low stringency (Tm-35 degrees) to 3 different HPV probes. By hybridization under high stringency conditions (Tm-20 degrees), the virus in each case was identified as being HPV2.

Identification of genital tract papillomaviruses HPV-6 and HPV-16 in warts of the oral cavity

Warty lesions of the oral cavity were examined for etiologic association with genital tract papillomaviruses HPV-6, HPV-11, and HPV-16. DNAs extracted from ten oral biopsies were screened for HPV genomic sequences by Southern transfer hybridization with 32P-labeled viral DNA probes. Nonstringent hybridization with an HPV-6 probe revealed papillomavirus DNA sequences in four of seven tissues with histologic evidence of papillomatosis, in none of two tissues without histologic evidence of papillomatosis, and in one tissue that was not examined by histology. Stringent hybridization tests with HPV-6 and HPV-16 probes identified the genome in one tissue as being HPV-16, in a second tissue as being HPV-6 subtype a, and in a third tissue as HPV-6 (subtype unidentified); papillomavirus DNA sequences in two tissues are as yet not identified. An additional case of HPV-6 or HPV-11 related oral cavity lesion was diagnosed by in situ hybridization of paraffin sections with a 35S-labeled, mixed HPV-6 + HPV-11 probe. The hybridization in the positive section was extensive and confined to epithelial nuclei. The oral lesions associated with genital tract papillomaviruses were asymptomatic, multiple or single, and were located in different parts of the oral cavity, for example, on the gingivae, on the tongue, on the lip, on the tonsillar pillar, and on the floor of the mouth.

Proliferative verrucous leukoplakia. A long-term study of thirty patients

Up to 6% of oral leukoplakia, a relatively common mucosal disease, can be expected to become malignant. This report describes a long-term study of 30 patients in whom a particular form of leukoplakia was identified and labeled proliferative verrucous leukoplakia (PVL), a disease of unknown origin, which exhibits a strong tendency to develop areas of carcinoma. PVL begins as a simple hyperkeratosis but tends to spread and become multifocal. PVL is slow-growing, persistent, and irreversible, and in time areas become exophytic, wartlike, and apparently resistant to all forms of therapy as recurrence is the rule. The disease was most commonly seen in elderly women and had been present for many years. Patients were followed for 1 to 20 years. Thirteen died of or with their disease, 14 were alive with PVL, and 3 were alive without PVL at last contact. PVL rarely regressed despite therapy. All patients who died had persistent or recurrent disease. PVL appears to constitute a continuum of hyperkeratotic disease, ranging from a simple hyperkeratosis at one end to invasive squamous cell carcinoma at the other. Microscopic findings are dependent upon the stage of the disease's development and the location and adequacy of the biopsy.

White, exophytic lesion of the left lateral surface of the tongue

Verrucous carcinoma is an unusual variant of squamous cell carcinoma; it comprises approximately 5% of all oral malignancies. The buccal mucosa, gingiva, and tongue are the most commonly involved areas within the oral cavity. Histologically, verrucous carcinoma can present a diagnostic dilemma. The basement membrane is often intact, which may cause the pathologist to misinterpret these carcinomas as hyperkeratosis and severe dysplasia. The preferred treatment for this lesion is wide local excision. Regional lymph node dissection is usually not necessary and radiation therapy appears to be contraindicated. Close follow-up is recommended.