Dermatology Online Journal

Cutaneous squamous cell carcinoma of the external auditory canal
Megan Nichole Bridges¹, Mariana Doval MD FCAP²
Dermatology Online Journal 15 (2): 13

1. Medical Student at Kansas City University of Medicine and Biosciences. mbridges@kcumb.edu
2. Pathologist, Columbia Hospital, West Palm Beach, Florida

---

Abstract

Cutaneous squamous cell carcinoma (SCC) along with basal cell carcinoma (BCC), collectively known as Nonmelanoma skin cancer (NMSC), are the most common cancers in the United States. Squamous cell carcinoma of the skin is less common than BCC, but is known to be more aggressive with a higher mortality rate. Squamous cell carcinoma of the external auditory canal (EAC) is rare when compared to SCC on other cutaneous sites. Due to the rarity of SCC originating in the EAC, there is currently no universal staging system, making it difficult to analyze data and form a treatment strategy. This is a case of a 76-year-old man who initially presented with actinic keratosis of the EAC that died in just over a year from metastatic cutaneous SCC.

---

Introduction

Nonmelanoma skin cancer (NMSC) is the most common cancer in the United States with an incidence 18-20 times greater than that of malignant melanoma [1]. The estimated annual incidence is greater than one million cases per year [2]. The lifetime risks of developing NMSC were estimated to be 29 percent to 55 percent for basal cell carcinoma (BCC) and 7-11 percent for squamous cell carcinoma (SCC) [3]. Eighty percent of NMSC are BCC and 20 percent are SCC [4]. Cutaneous SCC is known to metastasize and grow more rapidly than the more common BCC [5,6]. This is a report of an elderly man with an original biopsy of hypertrophic actinic keratosis in the external auditory canal (EAC) that quickly became invasive SCC and ultimately led to his demise. In the nine months prior to receiving treatment, the tumor had replaced his right auricle, extended to the tympanic membrane, middle ear, right parotid lymph node, and the right lateral pterygoid muscle.

Case

Figure 1A	Figure 1B
Figures 1A & 1B. Ulcerating and fungitating squamous cell carcinoma on presentation to the emergency department

A 76-year-old retired baker presented to a small community hospital's emergency department with a right ear malodorous mass that replaced his entire right auricle. The lesion appeared approximately nine months earlier in his external auditory canal and was initially 1.8 x 1.6 cm. The lesion was biopsied eight months prior to admission, which revealed changes compatible with the superficial portion of a hypertrophic actinic keratosis. He received Efudex (fluorouracil) on the lesion at the time of the original biopsy, but he never returned for his follow-up appointment scheduled one week later. The patient also had smaller lesions on his chin, nose, upper back, and right supra-clavicular region. The exudative right ear mass was bleeding at the time of presentation and was found to be superimposed with a Staphylococcus aureus infection (Figs. 1A & 1B). The tumor was evaluated to be T4, NX, MX, stage III, G2 and R2 [7]. Morphologically, the tumor showed dermal infiltration with irregular islands of well to moderately differentiated squamous cell carcinoma with focal prominent squamous pearl formation (Fig. 2A).

Figure 2A	Figure 2B
Figure 2A. Irregular islands of well- to moderately-differentiated squamous cell carcinoma with focal prominent squamous pearl formation (H&E, x10) Figure 2B. Focal mitotic activity with a desmoplastic response in the stroma (H&E, x40)

Focal mitotic activity was also noted and the stroma showed a desmoplastic response. Histologically, there was no evidence of angiolymphatic permeation (Fig. 2B). MRI and CT of the soft tissue of the head and neck as well as the brain with and without contrast revealed: a large right ear mass that extended along the tragus, antitragus, and had replaced the auricle and filled the external auditory canal. The mass extended to the tympanic membrane with thickening and probable atelectasis of the tympanic membrane as well as probable middle ear involvement. The ossicles were sclerotic on the right with generalized hyperostosis from this long-standing process. There was diffuse enhancement of this mass as well as ulceration and evidence of hemorrhage (Fig. 3).

Figure 3
Figure 3. Parasagittal T1 post-contrast MRI image through the right ear demonstrating enhancement and heterogeneity as well as focal areas of necrosis

Right parotid lymph node enlargement was noted, measuring 11 mm in maximum diameter. There was diffuse and extensive right mastoiditis. The mass also invaded the right lateral pterygoid muscle group and the massetor space on the right, which appeared to be contiguous. There was extension into the calvarium without evidence of intracranial extension. There was no sign of mass effect, shift, or hemorrhage and the brain was unremarkable for patient's age group (Fig. 4A & 4B).

Figure 4A	Figure 4B
Figure 4A. Axial T2 MRI of the CP angle demonstrating a large helical and auricular fungitating cauliflower-like mass occupying the entire external auditory canal. There is no definitive diploic space involvement, but there is ispsilateral mastoiditis. Figure 4B. Coronal post-contrast MRI through the mass in the plane of the dens. Demonstration of a large heterogeneously enhancing mass without involvement of the right temporal bone. There is normal enhancement of the left ear.

Tumor embolization was performed to help control bleeding before the patient was transferred to a large university hospital. There, the patient received a total auriclectomy (the resected area measuring approximately 8 cm x 11 cm) and a superficial parotidectomy sparing the facial nerve and its branches. He then had a lateral temporal bone resection followed by a deep lobe parotidectomy with resection of the lateral infratemporal fossa and a modified neck dissection (Fig. 5A). While the above procedures were being performed, the right arm was prepped and draped for removal of the radial forearm free flap to reconstruct the aforementioned defect (Fig. 5B). Each procedure was completed with no intraoperative complications. Following surgery, the patient was scheduled to receive post-operative radiation therapy which, at that time, was believed to stand a reasonable chance of being curative. Unfortunately, this patient's cancer had already metastasized and all further treatment was stopped because the patient was declared terminal. He died one year, one month, and a week after his original diagnosis of hypertrophic actinic keratosis.

Figure 5A	Figure 5B
Figure 5A. Post resection of lesion Figure 5B. Fore-arm free flap used to cover the defect.

Discussion

Most cases of cutaneous squamous cell carcinomas are easily treatable with an overall 5-year cure rate of > 90 percent [8] and a case fatality rate of only 1 percent [6]. Squamous cell carcinoma is the second most common malignancy of the skin occurring on the head and neck and is associated with a higher rate of metastasis than BCC. Tavin et al. reported a metastatic rate of 9.9 percent in their series of 387 patients with cutaneous SCC [9]. There are several predisposing conditions for SCC (Table 1) as well as factors associated with a poor prognosis (Table 2). Fortunately, there are several surgical and non-surgical treatment options currently available to treat cutaneous SCC, with Mohs Micrographic Surgery (MMS) shown to be the most effective treatment [4, 8]. The main advantage of MMS is the ability to examine 100 percent of the surgical margins, making incomplete excision less likely [62]. The cure rates reported for primary tumors treated with MMS were 93.3 percent and 94.8 percent [63, 64].

Our patient presented with invasive SCC that first began in the EAC. Carcinomas of the EAC occur each year in 1 of 5,000 to 15,000 patients with otologic disease [65]. SCC of the EAC is rare, with a prevalence of approximately one per million persons. Due to the rarity of these tumors, there is a lack of a universally accepted staging system, thus making it difficult to analyze data, formulate and evaluate a treatment strategy [66]. Preoperative clinical staging is difficult in these tumors because large parts of the temporal bone are not amenable to clinical examination [67]. Arriaga et al. [68] at the University of Pittsburgh, proposed a TNM staging system based on pre-therapeutic radiologic findings in CT scans and clinical examination (Table 3) [66, 67]. This staging system correlates well to the histopathologic tumor extension. From a surgical point of view, this system provides reliable and reproducible criteria for separating patients into TNM stages [66]. Depending on the stage of disease and treatment protocols, 5-year survival rates range from 10 percent for advanced disease to 83 percent for early disease [67]. The preferred treatment for cancer of the EAC and middle ear is radical surgery with tumor-free surgical margins and risk adapted postoperative radiotherapy [66, 67, 69]. The suggested surgery for complete resection of tumor of the EAC, middle ear, and temporal bone is a lateral temporal bone resection (resection of the bony external auditory canal, the tympanic membrane, the malleus and the incus with the medial limit of the incudostapedial joint), stage dependant, combined with a parotidectomy as well as a neck dissection [70, 71]. The most important survival factor is removal of the primary tumor with histologically clear margins [66, 67]. Pfreunder et al. found that the survival rate of patients with completely resected tumor was 100 percent, and of patients with tumor beyond surgical margins 66 percent at 5 years [67]. Moody et al. suggest that aggressive surgery for advanced tumors, especially those involving the dura, may not be in the patients' best interest, because prognosis remains poor with a 2-year survival of only 7 percent [72].

This patient's tumor initially presented as a small lesion of hypertrophic actinic keratosis in the external auditory canal. Within nine months, the lesion had completely replaced the right auricle, with extension to the tympanic membrane and the middle ear, as well as invasion into the right parotid lymph node and right lateral pterygoid muscle. Nine months after is original diagnosis, the patient underwent a right total auriclectomy, right parotidectomy, lateral temporal bone resection and a modified neck dissection followed by post-operative radiation. His treatment is consistent with several aforementioned studies which suggest that carcinoma of the external auditory canal and the middle ear should be treated by radical surgical excision and postoperative radiotherapy. For patients with advanced SCC (stages III and IV), such as this patient, incomplete resection can lead to recurrence despite post-operative radiation [73]. However, if our patient had returned to his follow-up appointment nine months prior, such drastic surgical measurements would not have been necessary and removal of the precursor lesion may have prevented his untimely death. In conclusion, a superficial biopsy read as actinic keratosis should not be disregarded, especially when found on high-risk areas such as the ear. Due to the possibility of malignant transformation of actinic keratosis to squamous cell carcinoma, these lesions should be treated appropriately and followed up with a repeat (deeper) biopsy if necessary in order to halt progression to a potentially lethal lesion.

References

1. Diepgen TL, Mahler VM. The epidemiology of skin cancer. Br J Dermatol. 2002 Apr;146(1):1-6. [PubMed]

2. American Cancer Society. Cancer Facts and Figures 2007.

3. Miller DL, Weinstock MA. Nonmelanoma skin cancer in the United States: Incidence. J Am Acad Dermatol. 1994 May;30(5 Pt 1):774-8. [PubMed]

4. Kwa RE, Campana K, Moy RL. Biology of cutaneous squamous cell carcinoma. J Am Acad Dermatol. 1992 Jan;26(1):1-26. [PubMed]

5. Epstein E, Epstein NN, Bragg K, Linden G. Metastases from squamous cell carcinoma of the skin. Arch Dermatol. 1968 Mar;97(3):245-51. [PubMed]

6. Clayman G, Lee J, Holsinger C, Zhou X, Duvic M, El-Naggar AK, et al. Mortality risk from squamous cell skin cancer. J Clin Oncol. 2005 Feb;23(4):759-65. [PubMed]

7. Greene FL. Carcinoma of the skin (excluding eyelid, vulva, and penis). In: American Joint Committee on Cancer: Cancer Staging Manuel (6th ed). New York (NY): Springer; 2002. p 205-08.

8. Rowe DE, Carroll RJ, Day CL Jr. Prognostic factors for local recurrence, metastasis, and survival rates in squamous cell carcinoma of the skin, ear and lip: implications for treatment modality selection. J Am Acad Dermatol. 1992 Jun;26(6):976-90. [PubMed]

9. Tavin E, Persky M. Metastatic cutaneous sqaumous cell carcinoma of the head and neck region. Laryngoscope. 1996 Feb(2 Pt 1);106:156-8. [PubMed]

10. Gallagher RP, Hill GB, Bajdik CD, Coldman AJ, Fincham S, McLean DI, Threlfall WJ. Sunlight exposure, pigmentation factors, and risk of nonmelanocytic skin cancer. II. Squamous cell carcinoma. Arch Dermatol. 1995 Feb;131(2):164-9. [PubMed]

11. Marks R, Rennie G, Selwood T. Malignant transformation of solar keratoses to squamous cell carcinoma. Lancet. 1988 Apr;1(9):795-7. [PubMed]

12. Lebwohl M. Actinic Keratosis: Epidemiology and progression to squamous cell carcinoma. Br J Dermatol. 2003 Nov;149 Suppl 66:31-3. [PubMed]

13. Salasche SJ. Epidemiology of actinic keratoses and squamous cell carcinoma. J Am Acad Dermatol. 2000 Jan;42(1 Pt 2):4-7. [PubMed]

14. Glogau RG. The risk of progression to invasive disease. J Am Acad Dermatol. 2000 Jan;42(1 Pt 2):23-4. [PubMed]

15. Marks R. Rennie G, Selweed TS. The relationship of basal cell carcinoma and squamous cell carcinoma to solar keratoses. Arch Dermatol. 1988 Jul;124(7):1039-42. [PubMed]

16. Dinehart SM, Nelson-Adesokan P, Cockerell C, Russell S, Brown R. Metastatic cutaneous squamous cell carcinoma derived from actinic keratosis. Cancer. 1997 Mar 1;79(5):920-3. [PubMed]

17. Guidelines of care for cutaneous squamous cell carcinoma: Committee of guidelines of care, task force on cutaneous squamous cell carcinoma. J Am Acad Dermatol. 1993 Apr;28(4):628-31. [PubMed]

18. Guenthner ST, Hurwitz RM, Buckel LJ, Gray HR. Cutaneous squamous cell carcinomas consistently show histologic evidence of in situ changes: A clinicopathologic correlation. J Am Acad Dermatol 1999 Sep;41(3 Pt 1):443-8. [PubMed]

19. Moon TE, Levine N, Cartmel B, Bangert JL, Rodney S, Dong Q, Peng YM, Alberts DS. Effect of retinol in preventing squamous cell skin cancer in moderate-risk subjects: a randomized, double-blind, controlled trial. Southwest skin cancer prevention study group. Cancer Epidemiol Biomarkers Prev. 1997 Nov;6(11):949-56. [PubMed]

20. Fitzpatrick TB, Johnson RA, Wolff K, Suurmond D. Albinism. In: Color Atlas and Synopsis of Clinical Dermatology. Common and Serious Diseases (5th Ed). New York (NY): McGraw-Hill; 2001. pgs 322-6.

21. Guo HR, Yu HS, Hu H, Monson RR. Arsenic in drinking water and skin cancers: cell-type specificity (Taiwan, R.O.C.). Cancer Causes and Control. 2001 Dec;12(10):909-16. [PubMed]

22. Cleaver JE, Crowley E. UV damage, DNA repair and skin carcinogenesis. Front Biosci. 2002 Apr 1;7:d1024-1043. [PubMed]

23. Jellouli-Elloumi A, Kochbati L, Dharaief S, Romdhane K, Maalej M. [Cancers arising from burn scars: 62 cases]. Ann Dermatol Venereol. 2003Apr;130(4):413-6. [PubMed]

24. Akguner M, Barutcu A, Yilmaz M, Karatas O, Vayvada H. Marjolin's ulcer and chronic burn scarring. J Wound Care. 1998 Mar;7(3):121-2. [PubMed]

25. Gallagher RP, Bajdik C, Fincham S, Hill GB, Keefe AR, Coldman A, McLean DI. Chemical exposures, medical history, and risk of squamous and basal cell carcinoma of the skin. Cancer Epidemiology, Biomarkers and Prevention. Jun 1996;5(6):419-24. [PubMed]

26. Suarez B, Lopez-Abente G, Martinez C, Navarro C, Tormo MJ, Rosso S. Occupation and skin cancer: The results of the HELIOS-I multicenter case-control study. BMC Public Health. 2007 Jul 26;7(147):180. [PubMed]

27. De Hertog SA , Wensveen CA, Bastiaens MT, Kielich CJ, Berkhout MJ, Westendorp RG, Vermeer BJ, Bouwes Bavinck JN; Leiden Skin Cancer Study. Relation between smoking and skin cancer. J Clin Oncol. 2001 Jan 1;19(1):231-8. [PubMed]

28. American Cancer Society. Cancer Prevention and Early Detection Facts and Figures 2007.

29. Armstrong BK, Kricker A. The epidemiology of UV induced skin cancer. J Photochem Photobiol B. 2001 Oct;63(1-3):8-18. Review. [PubMed]

30. Zanetti R, Rosso S, Martinez C, Nieto A, Miranda A, Mercier M, Loria DI, Østerlind A, Greinert R, Navarro C, Fabbrocini G, Barbera C, Sancho-Garnier H, Gafà L, Chiarugi A, Mossotti R. Comparison of risk patterns in carcinoma and melanoma of the skin in men: A multi-centre case-case-control study. Br J Cancer. 2006 Mar;94(5):743. [PubMed]

31. Koh D, Wang H, Lee J, Chia KS, Lee HP, Goh CL. Basal cell carcinoma, squamous cell carcinoma and melanoma of the skin: analysis of the Singapore cancer Registry Data 1969-97. Br J Dermatol. 2003 Jun;148(6):1161-6. [PubMed]

32. Halder RM, Bang KM. Skin cancer in blacks in the United States. Dermatol Clin. 1988 Jul;6(3):397-405. [PubMed]

33. Box NF, Duffy DL, Irving RE, Russell A, Chen W, Griffyths LR, Parsons PG, Green AC, Sturm RA. Melanocortin-1 receptor genotype is a risk factor for basal and squamous cell carcinoma. J Invest Dermatol. 2001 Feb;116(2):224-9. [PubMed]

34. Hemminki K, Zhang H, Czene K. Familial invasive and in situ squamous cell carcinoma of the skin. Br J Cancer. 2003 May 6;88(9):1375-80. [PubMed]

35. Nguyen P, Vin-Christian K, Ming M, Berger T. Aggressive squamous cell carcinomas in persons infected with the human immunodeficiency virus. Arch Dermatol. 2002 Jun;138(6):758-63. [PubMed]

36. Mork J, Lie AK, Glattre E, Hallmans G, Jellum E, Koskela P, Møller B, Pukkala E, Schiller JT, Youngman L, Lehtinen M, Dillner J. Human Papillomavirus Infection as a Risk Factor for Squamous Cell Carcinoma of the Head and Neck. N Engl J Med. 2001 Apr 12;344(15):1125-31. [PubMed]

37. Karagas MR, Nelson HH, Sehr P, Waterboer T, Stukel TA, Andrew A, Green AC, Bavinck JN, Perry A, Spencer S, Rees JR, Mott LA, Pawlita M. Human papillomavirus infection and incidence of squamous cell and basal cell carcinomas of the skin. J Nat Cancer Inst. 2006 Mar 15;98(6):389-95. [PubMed]

38. Perez-Reyes N, Farhi DC. Squamous cell carcinoma of head and neck in patients with well-differentiated lymphocytic lymphoma. Cancer. 1987 Feb 1;59(3):540-4. [PubMed]

39. Mehrany K, Weenig RH, Lee KK, Pittelkow MR, Otley CC. Increased metastasis and mortality from cutaneous squamous cell carcinoma in patients with chronic lymphocytic leukemia. J Am Acad Dermatol. 2005 Dec;53(6):1067-71. [PubMed]

40. Johnson TM, Rowe DE, Nelson BR, Swanson NA. Squamous cell carcinoma of the skin (excluding lip and oral mucosa). J Am Acad Dermatol. 1992 Mar;26(3 Pt 2):467-84. [PubMed]

41. Jensen P, Hansen S, Møller B, Leivestad T, Pfeffer P, Geiran O, Fauchald P, Simonsen S. Skin cancer in kidney and heart transplant recipients and different long-term immunosuppressive therapy regiments. J Am Acad Dermatol. 1999 Feb;40(2 Pt 2):177-86. [PubMed]

42. Berg D, Otley, CC. Skin cancer in organ transplant recipients: Epidemiology, pathogenesis, and management. J Am Acad Dermatol. 2002 Jul;47(1):1-17. quiz 18-20. [PubMed]

43. Martinez JC, Otley CC, Stasko T, Euvrard S, Brown C, Schanbacher CF, Weaver AL; Transplant-skin cancer collaborative. Defining the clinical course of metastatic skin cancer in organ transplant recipients. Arch Dermatol. 2003 Mar;139(3):301-6. [PubMed]

44. Euvrard S, Kanitakis J, Pouteil-Noble C, Disant F, Dureau G, Finaz de Villaine J, Claudy A, Thivolet J. Aggressive squamous cell carcinomas in organ transplant recipients. Transplant Proceedings. 1995 Apr;27(2):1767-8. [PubMed]

45. Cherpelis BS, Marcusen C, Lang PG. Prognostic factors for metastasis in squamous cell carcinoma of the skin. Dermatol Surg. 2002 Mar;28(3):268-73. [PubMed]

46. Karagas MR, Stukel TA, Greenberg ER, Baron JA, Mott LA, Stern RS. Risk of subsequent basal cell carcinoma and squamous cell carcinoma of the skin among patients with prior skin cancer. Skin cancer prevention study group. JAMA. 1992 Jun 24;267(24):3305-10. [PubMed]

47. Yoshinaga S, Hauptmann M, Sigurdson AJ, Doody MM, Freedman DM, Alexander BH, Linet MS, Ron E, Mabuchi K. Nonmelanoma skin cancer in relation to ionizing radiation exposure among U.S. radiologic technologists. Int J Cancer. 2005 Jul 10;115(5):828-34. [PubMed]

48. Lichter MD, Karagas MR, Mott LA, Spencer SK, Stukel TA, Greenberg ER. Therapeutic ionizing radiation and the incidence of basal cell carcinoma and squamous cell carcinoma. The New Hampshire Skin Cancer Study Group. Arch Dermatol. 2000 Aug;136(8):1007-11. [PubMed]

49. Duffield-Lillico AJ, Slate EH, Reid ME, Turnbull BW, Wilkins PA, Combs GF Jr, Park HK, Gross EG, Graham GF, Stratton MS, Marshall JR, Clark LC; Nutritional Prevention of Cancer Study Group. Selenium supplementation and secondary prevention of nonmelanoma skin cancer in a randomized trial. J Natl Cancer Inst. 2003 Oct 1;95(19):1477-81. [PubMed]

50. International Agency for Research on Cancer. The Evaluation of carcinogenic risk to humans. Solar and ultraviolet radiation. Lyon, France: International Agency for Research on Cancer; 1992; 55. IARC Monograhs.

51. Grossman D, Leffell DJ. The molecular basis of nonmelanoma skin cancer: New understanding. Arch Dermatol. 1997 Oct;133(10):1263-70. [PubMed]

52. de Gruiji FR, van Kranen HJ, Mulldenders LHF. UV-induced DNA damage, repair, mutations, and oncogenic pathways in skin cancer. J Photochem Photobiol B. 2001 Oct;63(1-3):19-27. [PubMed]

53. Kraemer KH, Lee MM, Andrews AD, Lambert WC. The role of sunlight and DNA repair in melanoma and nonmelanoma skin cancer. The Xeroderma Pigmentosum paradigm. Arch Dermatol. 1994 Aug;130(8):1018-21. [PubMed]

54. Broadland DG, Zitelli JA. Surgical margins for excision of primary cutaneous squamous cell carcinoma. J Am Acad Dermatol. 1992 Aug;27(2 Pt1):241-8. [PubMed]

55. Huang CC, Boyce SM. Surgical margins of excision for basal cell carcinoma and squamous cell carcinoma. Semin Cutan Med Surg. 2004 Sep;23(3):167-73. [PubMed]

56. Moore BA, Weber RS, Prieto V, El-Naggar A, Holsinger FC, Zhou X, Lee JJ, Lippman S, Clayman GL. Lymph node metastases from cutaneous squamous cell carcinoma of the head and neck. Laryngoscope. 2005 Sep;115(9):1561-7. [PubMed]

57. Griffiths RW, Feeley K, Suvarna SK. Audit of clinical and histological prognostic factors in primary invasive squamous cell carcinoma of the skin: Assessment in a minimum 5 year follow-up study after conventional excisional surgery. Br J Plastic Surg. 2002 Jun;55(4):287-92. [PubMed]

58. Lang PG Jr, Braun MA, Kwatra R. Aggressive squamous carcinomas of the scalp. Dermatol Surg. 2006 Sep;32(9):1163-70. [PubMed]

59. Grekin RC, Salmon PJM. Surgical management of local disease. In: Miller SJ, Maloney ME, eds. Cutaneous oncology: pathophysiology, diagnosis, and management. Malden, Mass.: Blackwell Science, 1998:506-517.

60. Dinehart SM, Pollack SV. Metastases from squamous cell skin cancer of the extremities. J Am Acad Dermatol. 1989 Aug;21(2 Pt 1):241-8. [PubMed]

61. Veness MJ. High-risk cutaneous squamous cell carcinoma of the head and neck. J Biomed Biotechnol 2007;2007(3):80572. Epub 2007 Apr 3. [PubMed]

62. Mohs FE, Snow SN. Microscopically controlled surgical treatment for squamous cell carcinoma of the lower lip. Surg Gynecol Obstet. 1985 Jan;160(1):37-41. [PubMed]

63. O'Brien CJ. The parotid gland as a metastatic basin for cutaneous cancer. Arch Otolaryngol Head Neck Surg. 2005 Jul;131(7):551-5. [PubMed]

64. delCharco J, Mendenhall WM, Parsons JT, Stringer SP, Cassisi NJ, Mendenhall NP. Carcinoma of the skin metastatic to the parotid area lymph nodes. Head Neck. 1998 Aug;20(5):369-73. [PubMed]

65. Crabtree JA, Britton BH, Pierce MK. Carcinoma of the external auditory canal. Laryngoscope. 1976 Mar;86(3):405-15. [PubMed]

66. Ogawa K, Nakamura K, Hatano K, Uno T, Fuwa N, Itami J, Kojya S, Nakashima T, Shinhama A, Nakagawa T, Toita T, Sakai M, Kodaira T, Suzuki M, Ito H, Murayama S. Treatment and prognosis of squamous cell carcinoma of the external auditory canal and middle ear: a multi-institutional retrospective review of 87 patients. Int J Radiation Oncology Biol Phys. 2007 Aug 1;68(5):1326-34. Epub 2007 Apr 18. [PubMed]

67. Pfreundner L, Schwager K, Willner J, Baier K, Bratengeier K, Brunner FX, Flentje M. Carcinoma of the external auditory canal and middle ear. Int J Radiat Oncol Biol Phys. 1999 Jul 1;44(4):777-88. [PubMed]

68. Arriaga M, Curtin H, Takahashi H, Hirsch BE, Kamerer DB. Staging proposal for external auditory meatus carcinoma based on preoperative clinical examination and computed tomography findings. Ann Otol Rhinol Larygnol. 1990 Sep;99(9 Pt 1):714-21. [PubMed]

69. Yeung P, Bridger A, Smee R, Baldwin M, Bridger GP. Malignancies of the external auditory canal and temporal bone: A review. ANZ J Surg. 2002 Feb;72(12):114-20. [PubMed]

70. Moore M, Deschler D, McKenna M, Varvares M, Lin D. Management outcomes following lateral temporal bone resection for ear and temporal bone malignancies. Otol-Head and Neck Surgery. 2007 Dec;137(6):893-8. [PubMed]

71. Kollert M, Draf W, Minovi A, Hofmann E, Bockmuhl U. [Carcinoma of the external auditory canal and middle ear: therapeutic strategy and follow up]. Laryngorhinootologie 2004 Dec;83(12):818-23. [PubMed]

72. Moody SA, Hirsch BE, Myers EN. Squamous cell carcinoma of the external auditory canal: An evaluation of a staging system. Am J Otol. 2000 Jul;21(4):582-8. [PubMed]

73. Nyrop M, Grontved A. Cancer of the External Auditory Canal. Arch Otolaryngol Head Neck Surg. 2002 Jul;128(7):834-7. [PubMed]

© 2009 Dermatology Online Journal