Eur Arch Otorhinolaryngol DOI 10.1007/s00405-014-2921-x
Otology
Clinical analysis of seborrheic keratoses in the ear: a retrospective study and literature review Kang Woo Kim · Jiwon Chang · Sunkyu Lee · Gi Jung Im · Sung Won Chae · Hak Hyun Jung · June Choi
Received: 17 December 2013 / Accepted: 28 January 2014 © Springer-Verlag Berlin Heidelberg 2014
Abstract The pathogenesis of a seborrheic keratosis has not been fully elucidated. In the present study, we reviewed the literature to increase the awareness of this disease among otolaryngologists and to stress the need for prompt diagnosis and treatment. This was a retrospective study in seven patients presenting with seborrheic keratoses in the ear. We included only those patients in whom keratoses were confirmed by pathology after a complete excision. In six patients, seborrheic keratoses were observed in the external auditory canal, and in one patient, they were observed in the auricle. The subtype of keratoses was classified as acanthotic in six patients; one patient had an unclassified type associated with basal cell carcinoma. Seborrheic keratoses are benign skin tumors; however, the lesions can recur after removal. Moreover, an association between seborrheic keratoses and malignant skin tumors has been reported. Therefore, otolaryngologists should consider a complete removal and histological examination of seborrheic keratoses.
SKs are often an incidental finding and they are generally benign, they should be distinguished clinically and histologically from other benign or malignant skin tumors [2, 3]. The pathogenesis of SKs is not well understood [1, 2, 4]. There is a number of established risk factors including older age, ultraviolet light exposure, human papillomavirus infection, fibroblast growth factor receptor 3 (FGFR3) gene and p110 α subunit of phosphoinositide 3-kinase (PIK3CA) oncogene mutations, hormonal factors, internal malignancy, and chronic skin infection [1, 4, 5]. To date, a limited number of reports on SKs in the ear have been published. In the current study, we described seven cases of SKs in the ear and reviewed the literature to increase the awareness of this disease among otolaryngologists and to stress the need for prompt diagnosis and treatment. The aim of the present study was to evaluate clinical appearance of SKs in the ear.
Keywords Seborrheic keratoses · Classification · Ear
Materials and methods
Introduction Seborrheic keratoses (SKs) are one of the most common skin tumors. They are frequently observed in adults on the trunk, extremities except palms and soles, head, and neck [1]. However, they rarely occur in the ear [1, 2]. Although K. W. Kim · J. Chang · S. Lee · G. J. Im · S. W. Chae · H. H. Jung · J. Choi (*) Department of Otorhinolaryngology, Head and Neck Surgery, Korea University College of Medicine, 123 Jeokgeum‑ro (Gojan‑Dong), Dawon‑gu, Ansan, Gyeonggi‑Do 425‑707, South Korea e-mail: [email protected]
A retrospective case review was performed using the charts of seven patients diagnosed with SKs in the ear at our institution between January 1992 and January 2012. We only included patients in whom SK had been confirmed by pathology after a complete excision. There were two women and five men; their mean age was 65 years, ranging from 47 to 82 years. The operated side was the right ear in five patients and the left in two. The surgery was carried out under local anesthesia. The lesions within the external auditory canal (EAC) were removed en bloc via a transcanal approach. The lesion of the auricle was removed under direct vision. In two patients, the lesions healed spontaneously and in three patients, they were primarily closed. However, in two patients, they could not be primarily
13
Eur Arch Otorhinolaryngol
Fig. 1 Basal cell carcinoma with SKs in the EAC is characterized by solid and nodular aggregations of neoplastic cells involving the dermis, with peripheral palisading of basaloid cells (a H&E, ×40, b H&E, ×200)
closed, and they were reconstructed with split-thickness skin grafts taken from the retroauricular skin. Prognosis as well as the association between SK subtype and malignancy and recurrence was analyzed 1 year after surgery.
Results SKs were located in the EAC in six patients and in the auricle in one patient. Patients complained of itching in the EAC (2 cases), otalgia (1 case), and otorrhea (1 case); in one case, it was an incidental finding and, in three cases, a growing mass was observed. Otorrhea was bloody. In the EAC, the size of the mass was 1 × 1 cm in four patients, 2 × 2 cm in one patient, and 3 × 2 cm in one patient; in the auricle, it was 2.5 × 2.5 cm in one patient. Large-sized SKs in the EAC were associated with basal cell carcinoma (Fig. 1). The common site of the SK was the posterior wall of the EAC (4 patients), inferior wall of the EAC (2 patients), and posterior surface of the auricle (1 patient). The shape was usually irregular (Table 1). The subtype of SKs was classified as acanthotic in six patients (Figs. 2, 3); one patient had an unclassified type associated with basal cell carcinoma. Recurrence was not observed in any of the patients at 1 year. The patient with an unclassified type was lost to follow-up at 1 year.
Discussion SKs are also known as verruca senilis, senile wart, seborrheic verruca, basal cell acanthoma, and basal cell papilloma [2]. They appear as solitary or multiple, roundto-oval, coin-like plaques of a variable size in various locations [6]. Lesions have a uniform light brown to black color and usually have a smooth or granular surface and
13
sharply delineated margins [2, 6]. They can appear anywhere on the body except the palms or soles [1, 2]. However, the most commonly affected sites are the chest, back, head, and neck [2]. Involvement of the ear is rare. SKs are usually asymptomatic, but sometimes they are associated with irritation, itching, pain, or bleeding and redness. In rare cases, tumors located around the eyelids or in the EAC can cause vision loss and conductive hearing loss [2, 6, 7]. In our study, patients complained of symptoms such as itching, otorrhea, otalgia, and growing mass. The exact epidemiology of SKs is unknown. However, it is known to be more prevalent among Caucasians and to equally affect men and women [2]. Usually, it is believed to increase with advancing age [2, 8]. In our study, the mean age of the patients was 65 years. Although the pathogenesis of SKs has not been fully elucidated, it is generally agreed that an older age significantly increases the risk of SKs. Exposure to ultraviolet light may also be involved in the pathogenesis of SKs [2, 8, 9]. Kwon et al. [8]. reported that patients with cumulative sunlight exposure of more than 6 h a day had a 2.28 times higher risk of SKs than those with less than 3 h of sunlight exposure per day. Recently, the involvement of a genetic predisposition and infection with human papillomavirus in the pathogenesis of SKs have also been suggested. However, detailed studies are needed to determine their role as etiological factors in developing SKs [2]. Molecular pathogenesis studies reported that SKs are monoclonal tumors and autonomous neoplasms rather than simple epidermal hyperplasia [2, 4, 5]. It is known that FGFR3 gene and PIK3CA oncogene mutations are involved in the molecular pathogenesis of SKs [2, 4, 5]. Hafner et al. [4] reported that FGFR3 mutations were present in three of five SKs, and one patient with the FGFR3 mutation additionally showed a hotspot PIK3CA mutation. Other studies have reported that the frequency of those mutations in SKs
×
×
Acanthotic M male, F female, Post posterior, Inf inferior, EAC external auditory canal
Acanthotic Irregular warty black
Irregular warty black Post. surface of the auricle of the right ear 2.5 × 2.5 Growing mass
Post. wall in the EAC of the left ear 1 × 1 Itching
F/79
F/57
2 × 2 1 × 1 1 × 1 3 × 2 M/60 M/63 M/66 M/82
Growing mass Otalgia Itching Growing mass
Inf. wall in the EAC of the left ear Inf. wall in the EAC of the right ear Post. wall in the EAC of the right ear Post. wall in the EAC of the right ear
Irregular warty pink Round warty pink Irregular warty black Irregular warty black
Acanthotic Acanthotic Acanthotic Unclassified
×
× × × O (basal cell carcinoma) ×
Complete excision with skin graft
× × × ×
×
Complete excision with skin graft Complete excision Complete excision Complete excision Complete excision with skin graft Complete excision × Acanthotic Irregular warty black Post. wall in the EAC of the right ear 1 × 1 M/47
Otorrhea
Site Size (cm) Chief complaint Sex/age
Table 1 Clinical characteristics of the patients diagnosed with SKs in the ear
Shape
Pathological type
Association with malignancy
Treatment
Recurrence after 1 year
Eur Arch Otorhinolaryngol
is from 25 to 90 % for FGFR3 and 16 % for PIK3CA [4]. FGFR3 mutations may already be present in initial lesions [2, 10], while it is still unknown which functional changes are caused by PIK3CA mutations in SKs. SKs may be classified into several microscopic variants: acanthotic, hyperkeratotic, adenoid, clonal, bowenoid, irritated, and melanoacanthoma [1, 2, 6, 11]. These subtypes can often overlap in SKs [2]. Hyperkeratosis and hyperpigmentation may be present to varying degrees. Hyperpigmentation has been estimated to be present in one-third of SKs [2]. The major subtypes are acanthotic, hyperkeratotic, and adenoid subtypes, of which the acanthotic subtype is the most common [1, 2, 7]. The acanthotic subtype involves pronounced acanthosis with marked basaloid cells. Horn cysts or pseudocysts are a characteristic microscopic finding. Papillomatosis and hyperkeratosis in the acanthotic subtype have been shown to be moderate. Moreover, proliferation of melanocytes and hyperpigmentation have been demonstrated in 30 % of the cases [2]. In our study, six cases had the acanthotic subtype of SKs with multiple horn cysts or pseudocysts. In the hyperkeratotic subtype, marked papillomatosis, hyperkeratosis, and a “church-spire” appearance (exophytic saw-tooth appearance with elongated projections) are observed. Horn cysts and pseudocysts might be present but are less common than in the acanthotic subtype. Hyperpigmentation is rather unusual [2]. The adenoid subtype is distinguished by reticular proliferation of double rows of basaloid epidermal cell tracts in the dermis. Horn cysts and pseudocysts are rare and hyperpigmentation is relatively common. It has been assumed that this subtype can develop from solar lentigo and ultimately reticulated fusion of the individual bands [2]. The diagnosis of SKs can usually be made based on clinical findings such as horn pseudocysts and pseudofollicular openings. However, the differential diagnosis should include several benign lesions such as actinic keratosis, fibroma, and verruca vulgaris and malignant skin tumors including basal cell carcinoma, squamous cell carcinoma, melanoma, and others [2, 3, 12–15]. The treatment of choice in SKs is removal of the lesion using one of the available methods including curettage, cryotherapy, ablative laser, use of topical vitamin D, and complete excision [2, 16]. SKs are benign skin tumors but they can locally recur after removal. They should be removed to prevent malignancy if a clinical finding is suspicious.
Conclusion Although SKs are known to be benign and rarely occur in the ear, an association between SKs and malignant skin tumors (e.g., basal cell carcinoma, squamous cell
13
Eur Arch Otorhinolaryngol
Fig. 2 SKs of auricle. a SKs of right auricle are presented with irregular and black appearance. b The lesion is radially symmetrical with keratin on its surface and several horn cyst. Keratin-filled horn cysts are surrounded by basaloid cells (H&E, ×100)
Fig. 3 SKs of EAC. a Multi-lobulated irregular shaped pink mass fills entrance of left EAC via endoscopic view. b Nest of squamous cells arranged in a sheet-like distribution enclose a small horn cyst.
13
(H&E, ×400) c Multi-lobulated irregular shaped black mass fills entrance of left EAC via endoscopic view. d Keratin-filled horn cysts are surrounded by basaloid cells (H&E, ×200)
Eur Arch Otorhinolaryngol
carcinoma, and malignant melanoma) has been reported. Therefore, otolaryngologists should consider the complete removal and histological examination of SKs. Acknowledgments This research was supported by the Communication Disorders Center, Korea University, Korea. Conflict of interest None of the authors have financial and personal relationships with other people or organizations that could inappropriately influence or bias their work to disclose.
References 1. Izquierdo Velasquez JC, Campos Mahecha AM, Duarte Silva JP (2012) Seborrheic keratosis of the external auditory canal. Otol Neurotol 33(7):e61–e62 2. Hafner C, Vogt T (2008) Seborrheic keratosis. J Dtsch Dermatol Ges 6(8):664–677 3. Ishida M, Ohsato N, Okabe H (2011) Basal cell carcinoma arising within a seborrheic keratosis with respect to immunohistochemical characteristics. Oncology lett 2(4):625–627 4. Hafner C, Vogt T, Landthaler M, Musebeck J (2008) Somatic FGFR3 and PIK3CA mutations are present in familial seborrhoeic keratoses. Br J Dermatol 159(1):214–217 5. Hafner C, Lopez-Knowles E, Luis NM, Toll A, Baselga E, Fernandez-Casado A, Hernandez S, Ribe A, Mentzel T, Stoehr R, Hofstaedter F, Landthaler M, Vogt T, Pujol RM, Hartmann A, Real FX (2007) Oncogenic PIK3CA mutations occur in epidermal nevi and seborrheic keratoses with a characteristic mutation pattern. Proc Natl Acad Sci U S A 104(33):13450–13454
6. Magliulo G, Appiani MC (2011) Seborrheic keratosis, keratotic type, of the external auditory canal. Otolaryngol Head Neck Surg 145(4):697–698 7. Kyrmizakis DE, Vrentzos EE, Papadakis CE, Chroniaris NE, Bizakis JG, Amanakis ZE (2002) Seborrheic keratosis of the auricle: report of an unusual case. Ear Nose Throat J 81(2):107–109 8. Kwon OS, Hwang EJ, Bae JH, Park HE, Lee JC, Youn JI, Chung JH (2003) Seborrheic keratosis in the Korean males: causative role of sunlight. Photodermatol Photoimmunol Photomed 19(2):73–80 9. Yeatman JM, Kilkenny M, Marks R (1997) The prevalence of seborrhoeic keratoses in an Australian population: does exposure to sunlight play a part in their frequency? Br J Dermatol 137(3):411–414 10. Logie A, Dunois-Larde C, Rosty C, Levrel O, Blanche M, Ribeiro A, Gasc JM, Jorcano J, Werner S, Sastre-Garau X, Thiery JP, Radvanyi F (2005) Activating mutations of the tyrosine kinase receptor FGFR3 are associated with benign skin tumors in mice and humans. Hum Mol Genet 14(9):1153–1160 11. Kim MP, Kim GI, Jung HH, Im GJ (2008) A case of hyperkeratotic seborrheic keratosis of the external auditory canal. Korean J Otorhinolaryngol Head Neck Surg 51:405–407 12. Jee H, Lee NR, Ahn SK (2013) Case of seborrheic keratosis with underlying basal cell carcinoma suggesting a collision tumor. J Dermatol 40(10):837–839 13. Repertinger S, Wang J, Adickes E, Sarma DP (2008) Melanoma in situ arising in seborrheic keratosis: a case report. Cases J 1(1):263 14. Terada T, Kamo M, Baba Y, Sugiura M (2012) Microinvasive squamous cell carcinoma arising within seborrheic keratosis. Cutis 90(4):176–178 15. Choi JH (2012) Seborrheic keratosis of the external auditory canal. Otol Neurotol 33(4):e27–e28 16. Asagami C, Muto M, Hirota T, Shimizu T, Hamamoto Y (1996) Anti-tumor effects of 1,25-dihydroxyvitamin D3 (1,25(OH)2D3) in seborrheic keratosis. J Investig Dermatol Symp Proc 1(1):94–96
13
Otology
Clinical analysis of seborrheic keratoses in the ear: a retrospective study and literature review Kang Woo Kim · Jiwon Chang · Sunkyu Lee · Gi Jung Im · Sung Won Chae · Hak Hyun Jung · June Choi
Received: 17 December 2013 / Accepted: 28 January 2014 © Springer-Verlag Berlin Heidelberg 2014
Abstract The pathogenesis of a seborrheic keratosis has not been fully elucidated. In the present study, we reviewed the literature to increase the awareness of this disease among otolaryngologists and to stress the need for prompt diagnosis and treatment. This was a retrospective study in seven patients presenting with seborrheic keratoses in the ear. We included only those patients in whom keratoses were confirmed by pathology after a complete excision. In six patients, seborrheic keratoses were observed in the external auditory canal, and in one patient, they were observed in the auricle. The subtype of keratoses was classified as acanthotic in six patients; one patient had an unclassified type associated with basal cell carcinoma. Seborrheic keratoses are benign skin tumors; however, the lesions can recur after removal. Moreover, an association between seborrheic keratoses and malignant skin tumors has been reported. Therefore, otolaryngologists should consider a complete removal and histological examination of seborrheic keratoses.
SKs are often an incidental finding and they are generally benign, they should be distinguished clinically and histologically from other benign or malignant skin tumors [2, 3]. The pathogenesis of SKs is not well understood [1, 2, 4]. There is a number of established risk factors including older age, ultraviolet light exposure, human papillomavirus infection, fibroblast growth factor receptor 3 (FGFR3) gene and p110 α subunit of phosphoinositide 3-kinase (PIK3CA) oncogene mutations, hormonal factors, internal malignancy, and chronic skin infection [1, 4, 5]. To date, a limited number of reports on SKs in the ear have been published. In the current study, we described seven cases of SKs in the ear and reviewed the literature to increase the awareness of this disease among otolaryngologists and to stress the need for prompt diagnosis and treatment. The aim of the present study was to evaluate clinical appearance of SKs in the ear.
Keywords Seborrheic keratoses · Classification · Ear
Materials and methods
Introduction Seborrheic keratoses (SKs) are one of the most common skin tumors. They are frequently observed in adults on the trunk, extremities except palms and soles, head, and neck [1]. However, they rarely occur in the ear [1, 2]. Although K. W. Kim · J. Chang · S. Lee · G. J. Im · S. W. Chae · H. H. Jung · J. Choi (*) Department of Otorhinolaryngology, Head and Neck Surgery, Korea University College of Medicine, 123 Jeokgeum‑ro (Gojan‑Dong), Dawon‑gu, Ansan, Gyeonggi‑Do 425‑707, South Korea e-mail: [email protected]
A retrospective case review was performed using the charts of seven patients diagnosed with SKs in the ear at our institution between January 1992 and January 2012. We only included patients in whom SK had been confirmed by pathology after a complete excision. There were two women and five men; their mean age was 65 years, ranging from 47 to 82 years. The operated side was the right ear in five patients and the left in two. The surgery was carried out under local anesthesia. The lesions within the external auditory canal (EAC) were removed en bloc via a transcanal approach. The lesion of the auricle was removed under direct vision. In two patients, the lesions healed spontaneously and in three patients, they were primarily closed. However, in two patients, they could not be primarily
13
Eur Arch Otorhinolaryngol
Fig. 1 Basal cell carcinoma with SKs in the EAC is characterized by solid and nodular aggregations of neoplastic cells involving the dermis, with peripheral palisading of basaloid cells (a H&E, ×40, b H&E, ×200)
closed, and they were reconstructed with split-thickness skin grafts taken from the retroauricular skin. Prognosis as well as the association between SK subtype and malignancy and recurrence was analyzed 1 year after surgery.
Results SKs were located in the EAC in six patients and in the auricle in one patient. Patients complained of itching in the EAC (2 cases), otalgia (1 case), and otorrhea (1 case); in one case, it was an incidental finding and, in three cases, a growing mass was observed. Otorrhea was bloody. In the EAC, the size of the mass was 1 × 1 cm in four patients, 2 × 2 cm in one patient, and 3 × 2 cm in one patient; in the auricle, it was 2.5 × 2.5 cm in one patient. Large-sized SKs in the EAC were associated with basal cell carcinoma (Fig. 1). The common site of the SK was the posterior wall of the EAC (4 patients), inferior wall of the EAC (2 patients), and posterior surface of the auricle (1 patient). The shape was usually irregular (Table 1). The subtype of SKs was classified as acanthotic in six patients (Figs. 2, 3); one patient had an unclassified type associated with basal cell carcinoma. Recurrence was not observed in any of the patients at 1 year. The patient with an unclassified type was lost to follow-up at 1 year.
Discussion SKs are also known as verruca senilis, senile wart, seborrheic verruca, basal cell acanthoma, and basal cell papilloma [2]. They appear as solitary or multiple, roundto-oval, coin-like plaques of a variable size in various locations [6]. Lesions have a uniform light brown to black color and usually have a smooth or granular surface and
13
sharply delineated margins [2, 6]. They can appear anywhere on the body except the palms or soles [1, 2]. However, the most commonly affected sites are the chest, back, head, and neck [2]. Involvement of the ear is rare. SKs are usually asymptomatic, but sometimes they are associated with irritation, itching, pain, or bleeding and redness. In rare cases, tumors located around the eyelids or in the EAC can cause vision loss and conductive hearing loss [2, 6, 7]. In our study, patients complained of symptoms such as itching, otorrhea, otalgia, and growing mass. The exact epidemiology of SKs is unknown. However, it is known to be more prevalent among Caucasians and to equally affect men and women [2]. Usually, it is believed to increase with advancing age [2, 8]. In our study, the mean age of the patients was 65 years. Although the pathogenesis of SKs has not been fully elucidated, it is generally agreed that an older age significantly increases the risk of SKs. Exposure to ultraviolet light may also be involved in the pathogenesis of SKs [2, 8, 9]. Kwon et al. [8]. reported that patients with cumulative sunlight exposure of more than 6 h a day had a 2.28 times higher risk of SKs than those with less than 3 h of sunlight exposure per day. Recently, the involvement of a genetic predisposition and infection with human papillomavirus in the pathogenesis of SKs have also been suggested. However, detailed studies are needed to determine their role as etiological factors in developing SKs [2]. Molecular pathogenesis studies reported that SKs are monoclonal tumors and autonomous neoplasms rather than simple epidermal hyperplasia [2, 4, 5]. It is known that FGFR3 gene and PIK3CA oncogene mutations are involved in the molecular pathogenesis of SKs [2, 4, 5]. Hafner et al. [4] reported that FGFR3 mutations were present in three of five SKs, and one patient with the FGFR3 mutation additionally showed a hotspot PIK3CA mutation. Other studies have reported that the frequency of those mutations in SKs
×
×
Acanthotic M male, F female, Post posterior, Inf inferior, EAC external auditory canal
Acanthotic Irregular warty black
Irregular warty black Post. surface of the auricle of the right ear 2.5 × 2.5 Growing mass
Post. wall in the EAC of the left ear 1 × 1 Itching
F/79
F/57
2 × 2 1 × 1 1 × 1 3 × 2 M/60 M/63 M/66 M/82
Growing mass Otalgia Itching Growing mass
Inf. wall in the EAC of the left ear Inf. wall in the EAC of the right ear Post. wall in the EAC of the right ear Post. wall in the EAC of the right ear
Irregular warty pink Round warty pink Irregular warty black Irregular warty black
Acanthotic Acanthotic Acanthotic Unclassified
×
× × × O (basal cell carcinoma) ×
Complete excision with skin graft
× × × ×
×
Complete excision with skin graft Complete excision Complete excision Complete excision Complete excision with skin graft Complete excision × Acanthotic Irregular warty black Post. wall in the EAC of the right ear 1 × 1 M/47
Otorrhea
Site Size (cm) Chief complaint Sex/age
Table 1 Clinical characteristics of the patients diagnosed with SKs in the ear
Shape
Pathological type
Association with malignancy
Treatment
Recurrence after 1 year
Eur Arch Otorhinolaryngol
is from 25 to 90 % for FGFR3 and 16 % for PIK3CA [4]. FGFR3 mutations may already be present in initial lesions [2, 10], while it is still unknown which functional changes are caused by PIK3CA mutations in SKs. SKs may be classified into several microscopic variants: acanthotic, hyperkeratotic, adenoid, clonal, bowenoid, irritated, and melanoacanthoma [1, 2, 6, 11]. These subtypes can often overlap in SKs [2]. Hyperkeratosis and hyperpigmentation may be present to varying degrees. Hyperpigmentation has been estimated to be present in one-third of SKs [2]. The major subtypes are acanthotic, hyperkeratotic, and adenoid subtypes, of which the acanthotic subtype is the most common [1, 2, 7]. The acanthotic subtype involves pronounced acanthosis with marked basaloid cells. Horn cysts or pseudocysts are a characteristic microscopic finding. Papillomatosis and hyperkeratosis in the acanthotic subtype have been shown to be moderate. Moreover, proliferation of melanocytes and hyperpigmentation have been demonstrated in 30 % of the cases [2]. In our study, six cases had the acanthotic subtype of SKs with multiple horn cysts or pseudocysts. In the hyperkeratotic subtype, marked papillomatosis, hyperkeratosis, and a “church-spire” appearance (exophytic saw-tooth appearance with elongated projections) are observed. Horn cysts and pseudocysts might be present but are less common than in the acanthotic subtype. Hyperpigmentation is rather unusual [2]. The adenoid subtype is distinguished by reticular proliferation of double rows of basaloid epidermal cell tracts in the dermis. Horn cysts and pseudocysts are rare and hyperpigmentation is relatively common. It has been assumed that this subtype can develop from solar lentigo and ultimately reticulated fusion of the individual bands [2]. The diagnosis of SKs can usually be made based on clinical findings such as horn pseudocysts and pseudofollicular openings. However, the differential diagnosis should include several benign lesions such as actinic keratosis, fibroma, and verruca vulgaris and malignant skin tumors including basal cell carcinoma, squamous cell carcinoma, melanoma, and others [2, 3, 12–15]. The treatment of choice in SKs is removal of the lesion using one of the available methods including curettage, cryotherapy, ablative laser, use of topical vitamin D, and complete excision [2, 16]. SKs are benign skin tumors but they can locally recur after removal. They should be removed to prevent malignancy if a clinical finding is suspicious.
Conclusion Although SKs are known to be benign and rarely occur in the ear, an association between SKs and malignant skin tumors (e.g., basal cell carcinoma, squamous cell
13
Eur Arch Otorhinolaryngol
Fig. 2 SKs of auricle. a SKs of right auricle are presented with irregular and black appearance. b The lesion is radially symmetrical with keratin on its surface and several horn cyst. Keratin-filled horn cysts are surrounded by basaloid cells (H&E, ×100)
Fig. 3 SKs of EAC. a Multi-lobulated irregular shaped pink mass fills entrance of left EAC via endoscopic view. b Nest of squamous cells arranged in a sheet-like distribution enclose a small horn cyst.
13
(H&E, ×400) c Multi-lobulated irregular shaped black mass fills entrance of left EAC via endoscopic view. d Keratin-filled horn cysts are surrounded by basaloid cells (H&E, ×200)
Eur Arch Otorhinolaryngol
carcinoma, and malignant melanoma) has been reported. Therefore, otolaryngologists should consider the complete removal and histological examination of SKs. Acknowledgments This research was supported by the Communication Disorders Center, Korea University, Korea. Conflict of interest None of the authors have financial and personal relationships with other people or organizations that could inappropriately influence or bias their work to disclose.
References 1. Izquierdo Velasquez JC, Campos Mahecha AM, Duarte Silva JP (2012) Seborrheic keratosis of the external auditory canal. Otol Neurotol 33(7):e61–e62 2. Hafner C, Vogt T (2008) Seborrheic keratosis. J Dtsch Dermatol Ges 6(8):664–677 3. Ishida M, Ohsato N, Okabe H (2011) Basal cell carcinoma arising within a seborrheic keratosis with respect to immunohistochemical characteristics. Oncology lett 2(4):625–627 4. Hafner C, Vogt T, Landthaler M, Musebeck J (2008) Somatic FGFR3 and PIK3CA mutations are present in familial seborrhoeic keratoses. Br J Dermatol 159(1):214–217 5. Hafner C, Lopez-Knowles E, Luis NM, Toll A, Baselga E, Fernandez-Casado A, Hernandez S, Ribe A, Mentzel T, Stoehr R, Hofstaedter F, Landthaler M, Vogt T, Pujol RM, Hartmann A, Real FX (2007) Oncogenic PIK3CA mutations occur in epidermal nevi and seborrheic keratoses with a characteristic mutation pattern. Proc Natl Acad Sci U S A 104(33):13450–13454
6. Magliulo G, Appiani MC (2011) Seborrheic keratosis, keratotic type, of the external auditory canal. Otolaryngol Head Neck Surg 145(4):697–698 7. Kyrmizakis DE, Vrentzos EE, Papadakis CE, Chroniaris NE, Bizakis JG, Amanakis ZE (2002) Seborrheic keratosis of the auricle: report of an unusual case. Ear Nose Throat J 81(2):107–109 8. Kwon OS, Hwang EJ, Bae JH, Park HE, Lee JC, Youn JI, Chung JH (2003) Seborrheic keratosis in the Korean males: causative role of sunlight. Photodermatol Photoimmunol Photomed 19(2):73–80 9. Yeatman JM, Kilkenny M, Marks R (1997) The prevalence of seborrhoeic keratoses in an Australian population: does exposure to sunlight play a part in their frequency? Br J Dermatol 137(3):411–414 10. Logie A, Dunois-Larde C, Rosty C, Levrel O, Blanche M, Ribeiro A, Gasc JM, Jorcano J, Werner S, Sastre-Garau X, Thiery JP, Radvanyi F (2005) Activating mutations of the tyrosine kinase receptor FGFR3 are associated with benign skin tumors in mice and humans. Hum Mol Genet 14(9):1153–1160 11. Kim MP, Kim GI, Jung HH, Im GJ (2008) A case of hyperkeratotic seborrheic keratosis of the external auditory canal. Korean J Otorhinolaryngol Head Neck Surg 51:405–407 12. Jee H, Lee NR, Ahn SK (2013) Case of seborrheic keratosis with underlying basal cell carcinoma suggesting a collision tumor. J Dermatol 40(10):837–839 13. Repertinger S, Wang J, Adickes E, Sarma DP (2008) Melanoma in situ arising in seborrheic keratosis: a case report. Cases J 1(1):263 14. Terada T, Kamo M, Baba Y, Sugiura M (2012) Microinvasive squamous cell carcinoma arising within seborrheic keratosis. Cutis 90(4):176–178 15. Choi JH (2012) Seborrheic keratosis of the external auditory canal. Otol Neurotol 33(4):e27–e28 16. Asagami C, Muto M, Hirota T, Shimizu T, Hamamoto Y (1996) Anti-tumor effects of 1,25-dihydroxyvitamin D3 (1,25(OH)2D3) in seborrheic keratosis. J Investig Dermatol Symp Proc 1(1):94–96
13
