- Email: [email protected]
Bilateral oral squamous papilloma in the soft palate – Report of case
polski przeglĄd otorynolaryngologiczny 3 (2014) 42–45
Available online at www.sciencedirect.com
ScienceDirect journal homepage: www.elsevier.com/locate/ppotor
Case Report/Kazuistyka
Bilateral oral squamous papilloma in the soft palate – Report of case Antonio Adilson Soares de Lima 1,*, Maria Helena Martins Tommasi 1, Jean Nunes dos Santos 2, Cassiano Lima Chaiben 1, Maria Ångela Naval Machado 1, Iran Vieira 1 1 2
Department of Stomatology, School of Dentistry, Universidade Federal do Paraná – UFPR, Curitiba/PR, Brazil Department of Stomatology, School of Dentistry, Universidade Federal da Bahia – UFBA, Salvador/BA, Brazil
article info
abstract
Article history:
Squamous papilloma is a generally benign lesion that arises from the stratified squa-
Recieved: 02.11.2013
mous epithelium of the skin, lips, oral cavity, tongue, pharynx, larynx, esophagus, cervix,
Accepted: 13.11.2013
vagina or anal canal. It is a result of infection with human papillomavirus. The lesions
Available online: 23.11.2013
are manifested in the form of whitish exophytic tissue growth that resembles a wart.
Keywords: Papilloma
they are suffering from secondary trauma. This article reports a case of oral squamous
The squamous papillomas that develop in the oral mucosa are usually painless, unless
Oral mucosa Tumor Virus Infections Human papillomavirus 16
papilloma in a female patient who presented two lesions located between the soft palate and oropharynx. Interestingly, the squamous papillomas had similar sizes and were bilateral. The lesions were totally removed by surgery and the diagnosis was confirmed by histopathological examination. The patient was followed clinically for one year and no recurrence was observed. © 2013 Polish Otorhinolaryngology - Head and Neck Surgery Society. Published by Elsevier Urban & Partner Sp. z o.o. All rights reserved.
Introduction The squamous papilloma is described as a benign proliferative lesion affecting the oral mucosa and originates from papillomavirus (PV) infection [1]. Until the present date, family Papillomaviridae contains 29 genera formed by 189 PV types isolated from humans (120 types), non-human mammals, birds and reptiles (64, 3 and 2 types, respectively) [2]. HPV types are often designated as high risk (oncogenic) or low risk (nononcogenic). The HPV low-risk types are
found in mucosal and cutaneous sites and can cause such benign lesions as verrucae vulgaris, papillomas and condylomata, and the lesions of focal epithelial hyperplasia [3]. Squamous papilloma presents clinically as an exophytic lesion, pedunculated, with fingerlike appearance and small size. The color of the lesion is usually whitish due to keratinization of the surface. Clinically, the lesion resembles a wart [1]. Oral squamous papilloma may manifest in the following regions: tongue, lips, tonsils, buccal mucosa, palate, gums, and the floor of mouth [4]. However, the anatomical regions most affected in the mouth are: tongue,
* Corresponding author at: Department of Stomatology, School of Dentistry, Universidade Federal do Paraná – UFPR, Rua Prefeito Lothário Meissner 632, Jardim Botånico, 80170-210 Curitiba/PR, Brazil. Tel.: +55 41 33604050. E-mail address: [email protected] (A.A.S. de Lima). 2084-5308/$ – see front matter © 2013 Polish Otorhinolaryngology - Head and Neck Surgery Society. Published by Elsevier Urban & Partner Sp. z o.o. All rights reserved.
http://dx.doi.org/10.1016/j.ppotor.2013.11.005
polski przeglĄd otorynolaryngologiczny 3 (2014) 42–45
lips, and soft palate. Among benign lesions affecting the oral mucosa, squamous papilloma is considered the most frequent with a prevalence of 7.5–17.8% [5, 6]. The mode of transmission of HPV is unclear. Oral lesions appear due to oral sex, by autoinoculation and the maternal–fetal. HPV is unable to penetrate the intact squamous epithelium, which requires the presence of microtraumas or damaged skin or mucous membranes [7]. Currently, the following methods are used for identification of PV in the infected tissues: ultramicroscopy, the PCR method and immunostaining [8]. In the histopathologic examination, some cellular changes can characterize their presence, such as acanthosis, hyperkeratosis of the epithelium, mild dysplasia, fingerlike shape of the epithelium and mild chronic inflammation in the connective tissue [1, 9]. The aim of this paper is to report a case of two squamous papillomas that appeared bilaterally in the region between the soft palate and oropharynx.
43
Fig. 2 – Exophytic growth composed mostly of parakeratinized, stratified, squamous epithelium arranged in papillary projections (HE 200T)
Report of case A Caucasian 36-year-old female sought treatment at the School of Dentistry, Universidade Federal do Paraná – UFPR (Curitiba, Brazi) complaining of two plaques in the throat. In the anamnesis, the patient reported no major systemic disease and any kind of addiction, such as the use of tobacco or alcohol. The intraoral examination revealed the presence of two white lesions in the region bordering the soft palate and oropharynx (Fig. 1). The lesions had a pedunculated base of support and an irregular surface with numerous little finger-like projections. There was no complaint of pain or discomfort. However, occasionally, the patient reported that food debris was retained on the lesions. The lesions had an average of seven years of evolution and increased slowly. According to the patient, the first lesion appeared on the right side. Six months later, she perceived the appearance of the second lesion on the opposite side. The patient denied the practice of unprotected oral sex and also not has had other similar
injuries in other body parts. Considering these findings, the diagnosis of oral squamous papilloma was established. The lesions were easily removed by excisional oral biopsy using a scalpel. The bismuth subgallate was used to obtain hemostasis at the site due to the difficulty in suturing the operated area. Then, the lesions were sent for histopathological examination for analysis. The histological sections revealed numerous exophytic projections characterized by the proliferation of keratinized stratified squamous epithelium. A core of fibrovascular tissue was observed in the more central region of the lesion (Fig. 2). An immunohistochemistry was performed which used the following antibodies: anti-cytokeratins 7, 10, 14, 16 and 18. An intense staining was observed the cells of the basal and suprabasal layers of the epithelium to the anti-cytokeratin 14 (Fig. 3). The anti-cytokeratin 16 marked superficial epithelial cells (Fig. 4). No immunostaining for Cytokeratins 7, 10 and 18 was observed. The patient was reevaluated at six months and one year after removal of the lesions. No recurrence was observed.
Discussion
Fig. 1 – Bilateral papillomas in the soft palate
The prevalence of HPV infection varies substantially among countries and according to lifestyle and age. HPV is a common sexually transmitted infection among men and women with a 70% higher incidence in sexually active females. The majority of HPV infections are asymptomatic and transient, especially in the young population [10]. In this case report, a young female patient developed two oral squamous papillomas expressed simultaneously and bilaterally. Furthermore, the patient said that she was not practicing oral sex. Clinical and histologic evidence of HPV infection usually develops 1–8 months after initial exposure [11]. This fact may explain the inability of the patient with an oral papilloma to be unable to determine the source of HPV infection.
44
polski przeglĄd otorynolaryngologiczny 3 (2014) 42–45
Fig. 3 – Basal and parabasal epithelial cells exhibited immunopositivity for cytokeratin 14 (CK14 200T)
The tongue and palate are considered the anatomical regions where the oral squamous papilloma occurs most often. The occurrence of multiple oral squamous papillomas and symmetrical location in the same patient is an unusual situation. Jenson et al. [12] observed five patients (4 male, 1 female) with multiple papillomas in their study. These lesions had the following distribution: (1) maxillary gingivae; (2) right and left commissures; (3) floor of mouth and tongue; (4) frenulum and mandibular gingivae; and (5) soft palate and left lateral tongue. The 4 males were 18, 24, 25, and 28 years of age; the female was 15. The patient in this case report presented two cauliflower shape lesions in the limit of the soft palate with the oropharynx. The differential diagnosis of an oral solitary squamous papilloma includes: verruciform xanthoma, and papillary hyperplasia [13]. Moreover, multiple lesions in the form of white cauliflower can be confused with condyloma acuminatum. Although the clinical features of the lesion were strongly suggestive of a case of squamous papilloma,
histopathological examination was essential to determine the definitive diagnosis of the lesions. According to Oliveira et al. [9], the following criteria can be used to establish the histopathological diagnosis of squamous papillomas: squamous epithelium arrayed in finger-like projections, normal maturation pattern and presence of hyperparakeratosis in the epithelium, koilocytosis as a result of perinuclear cytoplasmic vacuolization of cells of the spinous layer, producing of perinuclear pale/clear halos, and pyknosis and the occasional presence of basilar hyperplasia. Practically, almost all of these features described above were observed on histopathology. The immunohistochemical staining of epithelial cells has marked suprabasal and basal layers for anti-cytokeratin 14. Moreover, the anti-keratin 16 has marked cells of the superficial layer. These findings are in agreement with the results of Oliveira et al. [9]. It has been postulated that cytokeratin 14 is normally present in basal cells of keratinized and nonkeratinized epithelia [14, 15]. The expression of cytokeratin 14 is similar between normal epithelium and squamous papilloma. This indicates that changes in the cytoskeleton induced by HPV infection are unable to modify the expression of this protein [9]. When untreated, some HPV-induced lesions may regress spontaneously, persist as benign lesions, or progress to precancerous lesions and eventually, cancer [11]. If an oral squamous papilloma is not removed, it does not undergo involution and remains as a benign lesion. The patient in this case had two oral squamous papillomas that have grown for a few months and then stabilized. Surgical removal is the treatment of choice and can be performed with electrocautery, scapel, laser ablation, cryosurgery, or intralesional injections of interferon [13]. Due to the anatomical location and pedunculated attachment of the lesions, surgical removal by scalpel was decided. The bismuth subgallate was used to facilitate hemostasis after surgical removal. No recurrence was observed. However, recurrences may occur in immunocompromised patients associated with HIV/AIDS [16].
Authors' contributions/Wkład autorów According to order.
Conflict of interest/Konflikt interesu None declared.
Financial support/Finansowanie None declared.
Ethics/Etyka Fig. 4 – The superficial epithelial cells showed a positive staining for cytokeratin 15 (CK15 200T)
The work described in this article has been carried out in accordance with The Code of Ethics of the World Medical
polski przeglĄd otorynolaryngologiczny 3 (2014) 42–45
Association (Declaration of Helsinki) for experiments involving humans; EU Directive 2010/63/EU for animal experiments; Uniform Requirements for manuscripts submitted to Biomedical journals.
r e f e r e n c e s / p i s m i e n n i c t w o
[1] Neville BW, Damm DD, Allen CM, Bouquot JE. Patologia Oral e Maxilofacial, 3a. ed., Rio de Janeiro: Elsevier; 2009. [2] Bernard HU, Burk RD, Chen Z, van Doorslaer K, zur Hausen H, de Villiers EM. Classification of papillomaviruses (PVs) based on 189 PV types and proposal of taxonomic amendments. Virology 2010;401(1):70–79. [3] Abbey LM, Page DG, Sawyer DR. The clinical and histopathologic features of a series of 464 oral squamous cell papillomas. Oral Surg Oral Med Oral Pathol 1980;49 (5):419–428. [4] Al-Khateeb HT. Benign oral masses in a northern Jordanian population – a retrospective study. Open Dent J 2009;3:147– 153. [5] Bouquot JE, Gundlach KK. Oral exophytic lesions in 23,616 white Americans over 35 years of age. Oral Surg Oral Med Oral Pathol 1986;62(3):284–291. [6] Abdulai AE, Nuamah IK, Gyasi R. Head and neck tumours in Ghanaian children. A 20 year review. Int J Oral Maxillofac Surg 2012;41(11):1378–1382. [7] Pinheiro RS, de França TR, Rocha B, Ferreira DC, Ribeiro CM, Cavalcanti SM, et al. Human papillomavirus coinfection in the oral cavity of HIV-infected children. J Clin Pathol 2011; 64(12):1083–1087.
45
[8] Miller CS, White DK. Human papillomavirus expression in oral mucosa, premalignant conditions, and squamous cell carcinoma: a retrospective review of the literature. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 1996;82: 57–68. [9] Oliveira MC, Silveira EJ, Godoy GP, Amorim RF, Costa AL, Queiroz LM. Immunohistochemical evaluation of intermediate filament proteins in squamous papilloma and oral verrucous carcinoma. Oral Dis 2005;11(5):288–292. [10] Trottier H, Burchell AN. Epidemiology of mucosal human papillomavirus infection and associated diseases. Public Health Genomics 2009;12:291–307. [11] Brentjens MH, Yeung-Yue KA, Lee PC, Tyring SK. Human papillomavirus: a review. Dermatol Clin 2002;20(2): 315–331. [12] Jenson AB, Lancaster WD, Hartmann DP, Shaffer Jr EL. Frequency and distribution of papillomavirus structural antigens in verrucae, multiple papillomas, and condylomata of the oral cavity. Am J Pathol 1982;107(2):212–218. [13] Jaju PP, Suvarna PV, Desai RS. Squamous papilloma: case report and literature review. Int J Oral Sci 2010;2(4):222–225. [14] Heyden A, Huitfeldt HS, Koppang HS, Thrane PS, Bryne M, Brandtzaeg P. Cytokeratins as epithelial differentiation markers in premalignant and malignant oral lesions. J Oral Pathol Med 1992;21(1):7–11. [15] Depondt J, Shabana AH, Sawaf H, Gehanno P, Forest N. Cytokeratin alterations as diagnostic and prognostic markers of oral and pharyngeal carcinomas. A prospective study. Eur J Oral Sci 1999;107(6):442–454. [16] Carneiro TE, Marinho SA, Verli FD, Mesquita AT, Lima NL, Miranda JL. Oral squamous papilloma: clinical, histologic and immunohistochemical analyses. J Oral Sci 2009; 51(3):367–372.
Available online at www.sciencedirect.com
ScienceDirect journal homepage: www.elsevier.com/locate/ppotor
Case Report/Kazuistyka
Bilateral oral squamous papilloma in the soft palate – Report of case Antonio Adilson Soares de Lima 1,*, Maria Helena Martins Tommasi 1, Jean Nunes dos Santos 2, Cassiano Lima Chaiben 1, Maria Ångela Naval Machado 1, Iran Vieira 1 1 2
Department of Stomatology, School of Dentistry, Universidade Federal do Paraná – UFPR, Curitiba/PR, Brazil Department of Stomatology, School of Dentistry, Universidade Federal da Bahia – UFBA, Salvador/BA, Brazil
article info
abstract
Article history:
Squamous papilloma is a generally benign lesion that arises from the stratified squa-
Recieved: 02.11.2013
mous epithelium of the skin, lips, oral cavity, tongue, pharynx, larynx, esophagus, cervix,
Accepted: 13.11.2013
vagina or anal canal. It is a result of infection with human papillomavirus. The lesions
Available online: 23.11.2013
are manifested in the form of whitish exophytic tissue growth that resembles a wart.
Keywords: Papilloma
they are suffering from secondary trauma. This article reports a case of oral squamous
The squamous papillomas that develop in the oral mucosa are usually painless, unless
Oral mucosa Tumor Virus Infections Human papillomavirus 16
papilloma in a female patient who presented two lesions located between the soft palate and oropharynx. Interestingly, the squamous papillomas had similar sizes and were bilateral. The lesions were totally removed by surgery and the diagnosis was confirmed by histopathological examination. The patient was followed clinically for one year and no recurrence was observed. © 2013 Polish Otorhinolaryngology - Head and Neck Surgery Society. Published by Elsevier Urban & Partner Sp. z o.o. All rights reserved.
Introduction The squamous papilloma is described as a benign proliferative lesion affecting the oral mucosa and originates from papillomavirus (PV) infection [1]. Until the present date, family Papillomaviridae contains 29 genera formed by 189 PV types isolated from humans (120 types), non-human mammals, birds and reptiles (64, 3 and 2 types, respectively) [2]. HPV types are often designated as high risk (oncogenic) or low risk (nononcogenic). The HPV low-risk types are
found in mucosal and cutaneous sites and can cause such benign lesions as verrucae vulgaris, papillomas and condylomata, and the lesions of focal epithelial hyperplasia [3]. Squamous papilloma presents clinically as an exophytic lesion, pedunculated, with fingerlike appearance and small size. The color of the lesion is usually whitish due to keratinization of the surface. Clinically, the lesion resembles a wart [1]. Oral squamous papilloma may manifest in the following regions: tongue, lips, tonsils, buccal mucosa, palate, gums, and the floor of mouth [4]. However, the anatomical regions most affected in the mouth are: tongue,
* Corresponding author at: Department of Stomatology, School of Dentistry, Universidade Federal do Paraná – UFPR, Rua Prefeito Lothário Meissner 632, Jardim Botånico, 80170-210 Curitiba/PR, Brazil. Tel.: +55 41 33604050. E-mail address: [email protected] (A.A.S. de Lima). 2084-5308/$ – see front matter © 2013 Polish Otorhinolaryngology - Head and Neck Surgery Society. Published by Elsevier Urban & Partner Sp. z o.o. All rights reserved.
http://dx.doi.org/10.1016/j.ppotor.2013.11.005
polski przeglĄd otorynolaryngologiczny 3 (2014) 42–45
lips, and soft palate. Among benign lesions affecting the oral mucosa, squamous papilloma is considered the most frequent with a prevalence of 7.5–17.8% [5, 6]. The mode of transmission of HPV is unclear. Oral lesions appear due to oral sex, by autoinoculation and the maternal–fetal. HPV is unable to penetrate the intact squamous epithelium, which requires the presence of microtraumas or damaged skin or mucous membranes [7]. Currently, the following methods are used for identification of PV in the infected tissues: ultramicroscopy, the PCR method and immunostaining [8]. In the histopathologic examination, some cellular changes can characterize their presence, such as acanthosis, hyperkeratosis of the epithelium, mild dysplasia, fingerlike shape of the epithelium and mild chronic inflammation in the connective tissue [1, 9]. The aim of this paper is to report a case of two squamous papillomas that appeared bilaterally in the region between the soft palate and oropharynx.
43
Fig. 2 – Exophytic growth composed mostly of parakeratinized, stratified, squamous epithelium arranged in papillary projections (HE 200T)
Report of case A Caucasian 36-year-old female sought treatment at the School of Dentistry, Universidade Federal do Paraná – UFPR (Curitiba, Brazi) complaining of two plaques in the throat. In the anamnesis, the patient reported no major systemic disease and any kind of addiction, such as the use of tobacco or alcohol. The intraoral examination revealed the presence of two white lesions in the region bordering the soft palate and oropharynx (Fig. 1). The lesions had a pedunculated base of support and an irregular surface with numerous little finger-like projections. There was no complaint of pain or discomfort. However, occasionally, the patient reported that food debris was retained on the lesions. The lesions had an average of seven years of evolution and increased slowly. According to the patient, the first lesion appeared on the right side. Six months later, she perceived the appearance of the second lesion on the opposite side. The patient denied the practice of unprotected oral sex and also not has had other similar
injuries in other body parts. Considering these findings, the diagnosis of oral squamous papilloma was established. The lesions were easily removed by excisional oral biopsy using a scalpel. The bismuth subgallate was used to obtain hemostasis at the site due to the difficulty in suturing the operated area. Then, the lesions were sent for histopathological examination for analysis. The histological sections revealed numerous exophytic projections characterized by the proliferation of keratinized stratified squamous epithelium. A core of fibrovascular tissue was observed in the more central region of the lesion (Fig. 2). An immunohistochemistry was performed which used the following antibodies: anti-cytokeratins 7, 10, 14, 16 and 18. An intense staining was observed the cells of the basal and suprabasal layers of the epithelium to the anti-cytokeratin 14 (Fig. 3). The anti-cytokeratin 16 marked superficial epithelial cells (Fig. 4). No immunostaining for Cytokeratins 7, 10 and 18 was observed. The patient was reevaluated at six months and one year after removal of the lesions. No recurrence was observed.
Discussion
Fig. 1 – Bilateral papillomas in the soft palate
The prevalence of HPV infection varies substantially among countries and according to lifestyle and age. HPV is a common sexually transmitted infection among men and women with a 70% higher incidence in sexually active females. The majority of HPV infections are asymptomatic and transient, especially in the young population [10]. In this case report, a young female patient developed two oral squamous papillomas expressed simultaneously and bilaterally. Furthermore, the patient said that she was not practicing oral sex. Clinical and histologic evidence of HPV infection usually develops 1–8 months after initial exposure [11]. This fact may explain the inability of the patient with an oral papilloma to be unable to determine the source of HPV infection.
44
polski przeglĄd otorynolaryngologiczny 3 (2014) 42–45
Fig. 3 – Basal and parabasal epithelial cells exhibited immunopositivity for cytokeratin 14 (CK14 200T)
The tongue and palate are considered the anatomical regions where the oral squamous papilloma occurs most often. The occurrence of multiple oral squamous papillomas and symmetrical location in the same patient is an unusual situation. Jenson et al. [12] observed five patients (4 male, 1 female) with multiple papillomas in their study. These lesions had the following distribution: (1) maxillary gingivae; (2) right and left commissures; (3) floor of mouth and tongue; (4) frenulum and mandibular gingivae; and (5) soft palate and left lateral tongue. The 4 males were 18, 24, 25, and 28 years of age; the female was 15. The patient in this case report presented two cauliflower shape lesions in the limit of the soft palate with the oropharynx. The differential diagnosis of an oral solitary squamous papilloma includes: verruciform xanthoma, and papillary hyperplasia [13]. Moreover, multiple lesions in the form of white cauliflower can be confused with condyloma acuminatum. Although the clinical features of the lesion were strongly suggestive of a case of squamous papilloma,
histopathological examination was essential to determine the definitive diagnosis of the lesions. According to Oliveira et al. [9], the following criteria can be used to establish the histopathological diagnosis of squamous papillomas: squamous epithelium arrayed in finger-like projections, normal maturation pattern and presence of hyperparakeratosis in the epithelium, koilocytosis as a result of perinuclear cytoplasmic vacuolization of cells of the spinous layer, producing of perinuclear pale/clear halos, and pyknosis and the occasional presence of basilar hyperplasia. Practically, almost all of these features described above were observed on histopathology. The immunohistochemical staining of epithelial cells has marked suprabasal and basal layers for anti-cytokeratin 14. Moreover, the anti-keratin 16 has marked cells of the superficial layer. These findings are in agreement with the results of Oliveira et al. [9]. It has been postulated that cytokeratin 14 is normally present in basal cells of keratinized and nonkeratinized epithelia [14, 15]. The expression of cytokeratin 14 is similar between normal epithelium and squamous papilloma. This indicates that changes in the cytoskeleton induced by HPV infection are unable to modify the expression of this protein [9]. When untreated, some HPV-induced lesions may regress spontaneously, persist as benign lesions, or progress to precancerous lesions and eventually, cancer [11]. If an oral squamous papilloma is not removed, it does not undergo involution and remains as a benign lesion. The patient in this case had two oral squamous papillomas that have grown for a few months and then stabilized. Surgical removal is the treatment of choice and can be performed with electrocautery, scapel, laser ablation, cryosurgery, or intralesional injections of interferon [13]. Due to the anatomical location and pedunculated attachment of the lesions, surgical removal by scalpel was decided. The bismuth subgallate was used to facilitate hemostasis after surgical removal. No recurrence was observed. However, recurrences may occur in immunocompromised patients associated with HIV/AIDS [16].
Authors' contributions/Wkład autorów According to order.
Conflict of interest/Konflikt interesu None declared.
Financial support/Finansowanie None declared.
Ethics/Etyka Fig. 4 – The superficial epithelial cells showed a positive staining for cytokeratin 15 (CK15 200T)
The work described in this article has been carried out in accordance with The Code of Ethics of the World Medical
polski przeglĄd otorynolaryngologiczny 3 (2014) 42–45
Association (Declaration of Helsinki) for experiments involving humans; EU Directive 2010/63/EU for animal experiments; Uniform Requirements for manuscripts submitted to Biomedical journals.
r e f e r e n c e s / p i s m i e n n i c t w o
[1] Neville BW, Damm DD, Allen CM, Bouquot JE. Patologia Oral e Maxilofacial, 3a. ed., Rio de Janeiro: Elsevier; 2009. [2] Bernard HU, Burk RD, Chen Z, van Doorslaer K, zur Hausen H, de Villiers EM. Classification of papillomaviruses (PVs) based on 189 PV types and proposal of taxonomic amendments. Virology 2010;401(1):70–79. [3] Abbey LM, Page DG, Sawyer DR. The clinical and histopathologic features of a series of 464 oral squamous cell papillomas. Oral Surg Oral Med Oral Pathol 1980;49 (5):419–428. [4] Al-Khateeb HT. Benign oral masses in a northern Jordanian population – a retrospective study. Open Dent J 2009;3:147– 153. [5] Bouquot JE, Gundlach KK. Oral exophytic lesions in 23,616 white Americans over 35 years of age. Oral Surg Oral Med Oral Pathol 1986;62(3):284–291. [6] Abdulai AE, Nuamah IK, Gyasi R. Head and neck tumours in Ghanaian children. A 20 year review. Int J Oral Maxillofac Surg 2012;41(11):1378–1382. [7] Pinheiro RS, de França TR, Rocha B, Ferreira DC, Ribeiro CM, Cavalcanti SM, et al. Human papillomavirus coinfection in the oral cavity of HIV-infected children. J Clin Pathol 2011; 64(12):1083–1087.
45
[8] Miller CS, White DK. Human papillomavirus expression in oral mucosa, premalignant conditions, and squamous cell carcinoma: a retrospective review of the literature. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 1996;82: 57–68. [9] Oliveira MC, Silveira EJ, Godoy GP, Amorim RF, Costa AL, Queiroz LM. Immunohistochemical evaluation of intermediate filament proteins in squamous papilloma and oral verrucous carcinoma. Oral Dis 2005;11(5):288–292. [10] Trottier H, Burchell AN. Epidemiology of mucosal human papillomavirus infection and associated diseases. Public Health Genomics 2009;12:291–307. [11] Brentjens MH, Yeung-Yue KA, Lee PC, Tyring SK. Human papillomavirus: a review. Dermatol Clin 2002;20(2): 315–331. [12] Jenson AB, Lancaster WD, Hartmann DP, Shaffer Jr EL. Frequency and distribution of papillomavirus structural antigens in verrucae, multiple papillomas, and condylomata of the oral cavity. Am J Pathol 1982;107(2):212–218. [13] Jaju PP, Suvarna PV, Desai RS. Squamous papilloma: case report and literature review. Int J Oral Sci 2010;2(4):222–225. [14] Heyden A, Huitfeldt HS, Koppang HS, Thrane PS, Bryne M, Brandtzaeg P. Cytokeratins as epithelial differentiation markers in premalignant and malignant oral lesions. J Oral Pathol Med 1992;21(1):7–11. [15] Depondt J, Shabana AH, Sawaf H, Gehanno P, Forest N. Cytokeratin alterations as diagnostic and prognostic markers of oral and pharyngeal carcinomas. A prospective study. Eur J Oral Sci 1999;107(6):442–454. [16] Carneiro TE, Marinho SA, Verli FD, Mesquita AT, Lima NL, Miranda JL. Oral squamous papilloma: clinical, histologic and immunohistochemical analyses. J Oral Sci 2009; 51(3):367–372.