Type: Response Essays
Sample donated: Natasha Burke
Last updated: September 19, 2019
Adenoid cystic carcinomaof the external auditory- A Case Report Abstract: Background: Primary external auditorycanal (EAC) malignancies are very rare with adenoid cystic carcinoma (ACC)representing approximately 5% of these tumors. There is insufficient knowledge of thenatural behavior of ACC in EAC. Thedisease needs early detection and complete treatment because of its tendency torecur, vicinity to sensitive organs and lower response to radiation.
Case presentation: In this case study, we presented a case of youngfemale (37 years old) with right external auditory canal (EAC) mass which wasdiagnosed as a benigntumor, a postoperative biopsy confirmed it as ACC of theEAC which is a rare case in the literature. Conclusion: Here, we report a rare case of Adenoid Cystic Carcinoma (ACC)of External Auditory Canal (EAC) in a 37 years old Saudi female. Initial, Clinicaland CT findings were suggestive of a benign cystic mass but histopathologyexamination confirmed that tumor was ACCof EAC. The patient underwent to radical excision of the tumor along the complete excision ofsuperficial and deep part of carotid gland followed by adjuvant radiotherapy. Postsurgicalrecovery was uneventful with no sign of recurrence until one year of follow up. Keywords: Adenoid Cystic Carcinoma,External Auditory Canal, Computed tomography (CT), Adjuvant Radiotherapy. Background: Cancers of the external auditory canal (EAC)are extremely rare tumor with more than 80% being squamous cellcarcinomas and adenoid cystic carcinoma (ACC) accounting for approximately 5% ofall EAC Faisal D 2016, Safinaz Zainor2013.
Since 1894, only 106 cases of(ACC) involving the (EAC) havebeen reported in English literature Shao-Cheng Liua, 2012. Although itpresents a widespreadage distribution, peak incidence predominantly occurs among women, between the 5th and 6th decades of life Waldron CA2009. It is a slow growing but highly invasive cancer with a high recurrencerate. Lymphatic spread to the local lymph nodes is rare; however, It is notuncommon for distant metastasis, mainly to the lungs, that may occur over thecourse of many years Dong F 2008. Earlier diagnosis of these tumorsis of utmost importance, in view of the fact that delays in diagnosis may increases the risk of distant metastasis DongF 2008.
The propensity for perineural invasion and tendency for localrecurrence are well known in ACC patients Spiro RH 1986. The signs andsymptoms of this tumor do not alwayscorrelate with the histopathological diagnosis and subsequent clinical behavior of these tumors. Deep incisional biopsies need to be taken becausesuperficial biopsies may frequently miss such alesion Mohammad Hussham Arshad 2009 Aggressive surgical resection with adjuvant radiotherapy is the standardtreatment for local disease control Spiro RH 1986, Bhagat S 2012. However,there is a high risk of repeat local recurrence, because of the rarity of (ACC)of the (EAC), most of the observations drawn from various reports lack detailedcomparisons of pathological findings and long-term outcome follow-upShao-Cheng Liua , 2012. In this case study, we presented a case of young female with rightexternal auditory canal (EAC) mass which was diagnosed as benign tumor but postoperative biopsy confirmed it asACC of the EAC which is a rare case in the literature. Case Presentation: A 37-year-old female patient presented to our clinic with right externalauditory canal swelling associated with on and off earache with no ear dischargesfor a duration of 10 years, it had earlier been excised three times at privateclinics and histopathology reported as syringoma that was confirmed by ourpathologist after reviewing the outside slides. Clinical examination revealedthat the mass was occupying the concha and extended to the outer one third ofthe external auditory canal and causing partial obstruction of the canal (Figure1). Pure tone audiogram showed a mild conductive hearing loss at highfrequency.
The CT scan of temporal bone showed a well-defined faintly enhancingmass lesion measuring 8 x 10 x 13 mm which was pedunculated from the posteriorwall of the right external auditory canal, with no erosion of bone and noinvolvement of regional lymph node enlargement (Figure 2 A & B). Our findingswere suggestive of a benign etiology suchas papilloma or adenoma. Because the patient had been followed up by hematology for low platelet and hepato-splenomegaly she had chance to do Pet scanas part of her investigations that showed right external auditory canal nodule with mild metabolic activity, likely benign. Hepatosplenomegaly had no evidence of focal or hypermetaboliclesions. Only a single small hypermetabolic left external iliac lymph node withpossible reactive or inflammatory changes was observed.
Her bone marrow study confirmsthe diagnosis of Gaucher’s disease. Based on given information the swelling(likely benign), the patient underwent simple surgery for excision of the mass,later histopathological examination revealed adenoid cystic carcinoma. Microscopically, the tumor wascomposed of baseloid cells arranged in acribriform architecture (Figure 3). The tumorinfiltrated adjacent adipose tissue, skeletal muscles and very close to theelastic cartilage of the external auditory canal (Figure 4). Frequent perineural invasion was identified inthis patient (Figure 5).Immunohistochemistry confirmed the diagnosis thatshowed strong nuclear staining in the outer baseloidcells (P63 immunohistochemistry) and membranous positivity in the inner ductal cells(CK7 immunohistochemistry) as shown infigure 6 and 7 respectively.
After a thorough review of histopathological and immunochemical findings patientwas taken again to the operating room where moreradical surgery was done to excise the tumor along with the deep andsuperficial part of parotid gland to clear margins and the parotid glandis negative for malignancy (Figure8 & 9), keeping radiotherapy as adjuvanttool. The postoperative course wasuneventful and the excision site was well healed with no evidence of recurrenceuntil the last follow up (Figure 10).Prescription of the dose and technqiuesused for the RT administration Discussion: Adenoid Cystic Carcinomas (ACC) earlier known as cylindroma seldom arisein EAC, however,ACC is the most common lesion of glandular origin Dong Fet al 2008. This case of ACC involving a 37year old female is apparently the first case of Saudi Arabia. Earlierreports clearly show that female in their forties and fifties are more prone tothe AC Waldron CA1988, Dong F 2008, Choi JY 2003, our case being on the lower side of median age. The symptoms of our case include swelling of the the right external auditorycanal and partial hearing loss. Generally, the common clinical manifestations includeOtto rhea, regular pain, hearing loss and bleeding Arshad et al 2009. Therewas no discharge or bleeding in our case.
The etiology of ACC is not fullyunderstood. ACC appears to arise from the ceremonious glands, sweat glands orectopic salivary gland tissue Fliss DM 1990. In some cases, the tumor may have arisen in the adjacent parotidsalivary gland and secondarily may have extended into the ear canal Szanto PA 1984.In our case that mass was occupying theconcha and extended to the outer one-third of the external auditory canal and causing partialobstruction of the canal. Metastasis to regionallymph nodes and distant sites are well-documented so lungs and regional lymphnodes must also be evaluated with CT for metastasis.
MitulChaitan Bhatt 2016, SridharPS 2006, Degirmeni B 2004, Dong F 2008. Evidence of irregular bone erosion or destruction of the canal wall isindicative of malignancy Mitul ChaitanBhatt 2016. However, in our study PET scan of patient showedthat a faintly enhancing mass lesion was pedunculated from the posterior wallof the right external auditory canal, there was no erosion of bone and noinvolvement of regional lymph node enlargement.
Only a single small hypermetabolic left external iliac lymph node with possiblereactive or inflammatory changes was observed. Therefore,our findings were suggestive of a benign etiologysuch as papilloma or adenoma. Histologically, our findings showed that tumor cells were composed of baseloid cells arranged in cribriform architectureand were infiltrated to adipose tissues, skeletal muscles and towards elasticcartilage of the external auditory canal and presence of strong nuclearstaining in the outer baseloid cells (P63immunohistochemistry) andmembranous positivity in the inner ductal cells (CK7 immunohistochemistry). Ourfindings were in favor of Fliss DM 1990 and Shao-Cheng Liua 2012.
In addition to that, in our patient we observed the frequent perineuralinvasion which is a classical characteristic and diagnostically helpful featureof adenoid cystic carcinoma Hicks GW 1983, Shao-Cheng Liua 2012. Moreover,according to Nemzek WR 1998, ACC is the second most common tumor associated to perineural invasion after squamous cells carcinoma. Thesefindings confirmed the diagnosis of ACC of the EAC with perineural invasion andinvolvement of the tympanic portion of the temporal bone Shao-Cheng Liua 2012. After ACC of EACconfirmation, a radical surgery was done and postoperative radiotherapy wasgiven to our patient in order to reduce localrelapses Faisal D 2016. Although data from randomized trials is lacking, mostpractitioners consider such treatment to be beneficial. Garden AS 1995, BalamuckiCJ 2012, Simpson JR 1984, Al though,postoperative radiation seems to improve local control rates, the impact onACC-specific survival is not clear Oplatek A 2010. Conclusion: ACC of the EAC is a rare malignant tumor.
This tumor has an aggressive behavior characterized by local invasivenessand a metastatic risk of approximately 30%. There is insufficient knowledge ofthe natural behavior of ACC in EAC. Wewould like to emphasize the need for early detection of adenoid cysticcarcinoma of the external auditory canal and its differentiation from otherbenign conditions and therefore we encourage other authors to report casesconcerning diagnostic and treatment difficulties of this malignancy. Abbreviations: ACC: Adenoid Cystic Carcinoma;EAC: External Auditory Canal; RT: Radiotherapy.