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Salivary gland choristoma of the middle ear: A case report
Salivary Gland Choristoma of the Middle Ear: A Case Report Seung Lyong Ha, MD, Jung-Eun Shin, MD, and Tae Hyun Yoon, MD, PhD A choristoma is a nonneoplastic proliferation of histologically normal tissue that forms at an abnormal site. It is extremely uncommon in the middle ear space. It appears to be a developmental abnormality and may be associated with abnormalities of adjacent structures. It usually occurs with unilateral conductive hearing loss and requires a differential diagnosis from other mass lesions in the middle ear cavity. This article discusses a case of salivary gland choristoma of the middle ear that we believe to be the 24th case reported on this subject. (Am J Otolaryngo12000;21:127-130. Copyright © 2000 by W.B. Saunders Company)
(Editorial Comment: This rare disease should be considered in the differential diagnosis of a middle ear mass. Surgical therapy may be curative.)
Choristoma is a case in which the histologically normal tissue is located in unusual locations other than its original site. 1 Salivary gland choristoma is a normal salivary gland tissue that appears in locations other than the salivary glands. It is known to possibly arise in the middle ear cavity. Because most of the salivary gland choristomas in the middle ear cavity occur unilaterally without tympanic membrane (TM) perforation and cause conductive hearing loss, it becomes necessary to make a differential diagnosis from other mass lesions in the middle ear cavity. In 1961, Taylor and Martin 2 reported a case of salivary gland choristoma in the middle ear cavity in a patient with unilateral conductive hearing loss. Since that occurrence, a total of 22 cases have been reported in literature. 1-21 We report a case of unique salivary gland choristoma in which the patient was a 3-yearold girl, the youngest patient among the cases reported to date. CASE REPORT
A 3-year-old girl suffered from right-sided otalgia that occurred at a frequency of once From the Department of Otolaryngology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea. Address reprint requests to Tae Hyun Yoon, MD, PhD, Asan Medical Center, Songpa-ku Poongnap-dong 388-1, Seoul, Korea, 138-736. Copyright © 2000 by W.B. Saunders Company 0196-0709/00/2102-0011 $10.0(3/0
every month since she was 2 months old. She also had suppurative otorrhea in the right ear. Right-sided hearing loss and delayed language development were suspected; however, the patient had no other symptoms. She was born through normal vaginal delivery and received all vaccinations as scheduled. The patient also had a history of failed insertion of a ventilation tube in a local ear, nose, and throat clinic i year ago. The patient's general condition was fair, and both earlobes and external auditory meatus were found to be normal. A whitish mass that seemed to be protruding at the center of the right TM without any perforation was observed. There were no additional specific findings noticed in further head and neck examination. Tympanogram showed flat type B in the right ear and normal type A in the left ear. Stapedial reflex was absent in the right ear, and results of other routine laboratory examinations such as complete blood count, urine analysis, liver function test, electrocardiogram, and chest radiograph were within normal limits. In the temporal bone computed tomography scan, soft tissue density that filled the right middle ear cavity and pushed the TM to the lateral side was identified (Fig 1). Additional soft tissue densities were observed in the tympanic isthmus and mastoid cavity. However, there was no evidence of ossicular destruction. With a presumed diagnosis of congenital cholesteatoma, a right tympanotomy was performed on May 6th, 1996. The mass within the
American Journal of Otolaryngology,Vo121, No 2 (March-April),2000: pp 127-130
127
128
HA, SHIN, AND YOON
Fig 1. Coronal view of a temporal bone CT. The middle ear cavity was filled with soft tissue density. The handle of malleus (arrow) was encircled by soft tissue mass, but no definite malleus destruction was observed.
Fig 3. Seromucinous glands (arrows) were admixed with mature adipose (A) and fibrous (F) tissues. All tissues could be observed in normal salivary glands. (Hematoxylin and eosin, original magnification × 100.)
middle ear cavity was exposed and was whitish and elastic in appearance (Fig 2). The mass appeared to be attached to the lateral portion of the middle ear, which resulted in the bulging appearance of the TM. It also seemed to extend anteriorly to the eustachian tube orifice and encircle the medial and lateral side of the malleus handle. The entire mass, including the part of the mass that was adhesive to the TM, was easily removed from the malleus handle without causing any injury to the ossicles and the chorda tympani nerve. The mass was found to be 10 × 5 × 3 m m in size, and the portion that extended to the eustachian tube orifice was elastic and yellowish. Canal-up mastoidectomy was performed, and good pneumatization of the air cells was observed. There were no other specific findings
noted with the exception of some mucosal swelling within the mastoid cavity. Good aeration between the middle ear and the mastoid was maintained. Histopathologic study revealed seromucinous glands, identified as histopathologically normal salivary gland tissue (Fig 3), mingled with some fat tissue and fibrous tissue. The patient was discharged without any complications on the 7th day after the operation. Postoperative impedance audiogram, pure-tone audiometry, and stapedial reflex test showed no change compared with preoperative data. At the patient's last visit, she was free of any symptoms. Physical examination showed no evidence of recurrence during a 36-month followup period. The patient is scheduled for another follow-up visit in 6 months.
Fig 2. Operative findings. After elevation of tympanomeatal flap, a mass (M) was found in the middle ear cavity. It was attached to the tympanic membrane and encircled the handle of the malleus (arrows), The mass was of a Iobulated nature and extended to the eustachian tube orifice. (A) Before removal of the mass (M). (B) After removal of the mass.
CHORISTOMA
DISCUSSION In the review of literature, 23 cases of middle ear cavity salivary choristoma have been reported. The distribution of patients was between the ages of 3 to 52, with a mean age of 17.5 and an approximate 1:2 male to female ratio. In 1961, Taylor and Martin 2 reported a case of a 31-year-old woman with unilateral conductive hearing loss. In this case, a mass within the middle ear cavity was observed during the physical examination, and although the mass was removed, temporary facial palsy was present as a complication of surgery. Operative findings showed that the mass was adjacent to the facial nerve, and an abnormality of the incus was also being observed. In 1962, Steffen and House 3 reported a case of a 51-year-old woman with similar s y m p t o m s and no definite abnormalities within the middle ear cavity. In 1984, Kartush and Graham 4 summarized 12 cases that had been reported up to that date. Based on intraoperative findings, they reported a high incidence of ossicle deformity associated with salivary gland choristoma of the middle ear. The incus was absent in 4 cases, and deformed incus was observed in 7 cases. In 5 other cases, there were no stapes, and deformed stapes were found in 6 other cases. In 1995, Namdar et al I summarized 20 cases with emphasis on the facial nerve abnormality and reported a total of 9 cases of exposed facial canal, 3 cases that showed abnormal course of the facial nerve, and 4 cases of postoperative facial palsy. Even though 3 patients experienced facial palsy only temporarily, in 1 case the patient became permanently paralyzed; thus, Namdar insisted on intraoperative monitoring of facial nerve in their practice. Although salivary gland choristoma usually seems to cause unilateral conductive hearing loss as its most common symptom, there have also been cases of bilateral hearing loss, 5,6 associated otorrhea and tinnitus, 2,7,8 and other cases with deformed external ear. 5,9 In the operative findings to date, there have been many cases of deformity found in the ossicles and/or facial nerve. Excluding those, there were also other cases associated with round w i n d o w obstruction, inner ear deformity, and mass lesions that had developed within the mastoid cavity. 5,6,9
129
In 1992, Gejas Mendez ~° reported on the youngest patient to date--is a 3-year-old girl with salivary gland choristoma and a dermoid cyst. The patient in our case was also a 3-yearold girl, who was the same age of the youngest patient among the cases reported to date. The patient was admitted with otalgia and otorrhea as the chief complaint and, although hearing disturbance was highly suspected, no evidence of malformation was found. Operative findings also showed no ossicle destruction and no other specific malformations except for the mass that encircled the handle of the malleus. Facial nerve was also observed in its normal route. Postoperatively, there was no complication, and outpatient-based followups have shown no evidence of recurrence of the disease thus far. Although the exact mechanism of the development of heterophic salivary gland in the middle ear has not yet been determined, according to the theory inspired by Patten, 22 the malformed expansion of the remnant parotid epithelium or pharyngeal endoderm appears to correspond with the salivary gland of the middle ear cavity. On the 4th month of the embryological period, malformations of the incus, stapes, and facial nerve may be accompanied by the embryological failure of the 2nd aortic arch. Usually, the disease develops at various ages in patients who show unilateral conductive hearing loss without TM perforation and whose middle ear cavity, under radiographic examination shows mass-like lesions that can be differentiated from glomus tumors, schwannomas, rhabdomyosarcomas, dermoid cysts, or other teratomas and lymphomas. Treatment principles consider conservative surgical removal of the mass before everything else because complete radical excision of the mass might cause facial palsy and, even if the mass is incompletely removed, no cases have been reported on recurrence or continuous growth of the mass to date. CONCLUSION Salivary gland choristoma is a rare disease that requires a differential diagnosis from other middle ear mass lesions that can cause unilateral conductive hearing loss. Choristoma is often associated with various other malforma-
130
tions. Malformation of the facial nerve occurs frequently enough to increase the possibility of facial nerve injury during surgery. To avoid this condition, caution is required. REFERENCE 1. Namdar I, Smouha EE, Kane P: Salivary gland choristoma of the middle ear: Role of intraoperative facial nerve monitoring. Otolaryngol Head Neck Surg 112:616-620, 1995 2. Taylor G, Martin H: Salivary gland tissue of the middle ear. Arch Otolaryngol 73:49-51, 1961 3. Steffen T, House W: Salivary gland choristoma of the middle ear. Arch Otolaryngol 76:74-75, 1962 4. Kartush JM, Graham MD: Salivary gland choristoma of the middle ear: A case report and review of the literature. Laryngoscope 94:228-230, 1984 5. Peron DL, Schuknecht HF: Congenital cholesteatoma with other anomalies. Arch Otolaryngol 101:498505, 1975 6. Wine CJ, Metcalf JE: Salivary gland choristoma of the middle ear and mastoid. Arch Otolaryngol 103:485-436, 1977 7. Hociota D, Ataman T: A case of salivary gland choristoma of the middle ear. J Laryngol Otol 89:10651068, 1975 8. Saeger KL, Gruskin P, Carberry JN: Salivary gland choristoma of the middle ear. Arch Pathol Lab Med 106:39-40, 1982 9. Caplingar CB, Hera JF: Middle ear choristoma with absent window: A report of one case. Arch Otolaryngol 85:39-40, 1967 10. Cejas Mendez DL: Choristoma of the salivary gland
HA, SHIN, AND YOON
and darmoid cyst of the middle ear in a 3-year-old girl. Apropos of a case. A n Otorrhinolaiyngol Ibero Am 19:275282, 1992 11. Noguara JT, Hasse RF: Congenital ossicular defects with a normal auditory canal: Its surgical treatment. Eye, Ear, Nose, Throat Monthly 43:37-39, 1964 12. Brunar RC: Salivary gland choristoma o f t h e m i d d l e ear: A case report. Arch Otolaryngol 91:303, 1970 13. Mischke RE, Brackmann DE, Gruskin P: Salivary gland choristoma of the middle ear. Arch Otolaryngol 103:432-434, 1977 14. Abadir WF, Pease WS: Salivary gland choristoma of the middle ear. l Laryngol Oto192:247-252, 1978 15. Kley HA: Monomorphous tubular salivary gland adenoma of the middle ear. Laryngol Rhinol 58:65-67, 1979 16. Cannon CR: Salivary gland choristoma of the middle ear. Am J Otol 1:250-251, 1980 17. Quaranta A, Mininni F, Resta L: Salivary gland choristoma of the middle ear: A case report. J Laryngol Oto195:953-956, 1981 18. Moore PJ, Benjamin BNP, Kan AE: Salivary gland choristoma of the middle ear. Int J Ped Otorhinolaryngol 8:91-95, 1984 19. Bottrill ID, Chawla OP, Ramsay AD: Salivary gland choristoma of the middle ear. J Laryngol Oto1106:630-632, 1992 20. Hinni ML, Beatty CW: Salivary gland choristoma of the middle ear: Report of a case and review of the literature. Ear Nose Throat J 75(7):422-424, 1996 21. A n d e r h u b e r W, Beham A, Walch C, et ah Choristoma of the middle ear. Eur Arch Otorhinolaryngol 253: 182-184, 1996 22. Patten BM: H u m a n embryology (ed 3). New York, NY: McGraw-Hill, 1968
(Editorial Comment: This rare disease should be considered in the differential diagnosis of a middle ear mass. Surgical therapy may be curative.)
Choristoma is a case in which the histologically normal tissue is located in unusual locations other than its original site. 1 Salivary gland choristoma is a normal salivary gland tissue that appears in locations other than the salivary glands. It is known to possibly arise in the middle ear cavity. Because most of the salivary gland choristomas in the middle ear cavity occur unilaterally without tympanic membrane (TM) perforation and cause conductive hearing loss, it becomes necessary to make a differential diagnosis from other mass lesions in the middle ear cavity. In 1961, Taylor and Martin 2 reported a case of salivary gland choristoma in the middle ear cavity in a patient with unilateral conductive hearing loss. Since that occurrence, a total of 22 cases have been reported in literature. 1-21 We report a case of unique salivary gland choristoma in which the patient was a 3-yearold girl, the youngest patient among the cases reported to date. CASE REPORT
A 3-year-old girl suffered from right-sided otalgia that occurred at a frequency of once From the Department of Otolaryngology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea. Address reprint requests to Tae Hyun Yoon, MD, PhD, Asan Medical Center, Songpa-ku Poongnap-dong 388-1, Seoul, Korea, 138-736. Copyright © 2000 by W.B. Saunders Company 0196-0709/00/2102-0011 $10.0(3/0
every month since she was 2 months old. She also had suppurative otorrhea in the right ear. Right-sided hearing loss and delayed language development were suspected; however, the patient had no other symptoms. She was born through normal vaginal delivery and received all vaccinations as scheduled. The patient also had a history of failed insertion of a ventilation tube in a local ear, nose, and throat clinic i year ago. The patient's general condition was fair, and both earlobes and external auditory meatus were found to be normal. A whitish mass that seemed to be protruding at the center of the right TM without any perforation was observed. There were no additional specific findings noticed in further head and neck examination. Tympanogram showed flat type B in the right ear and normal type A in the left ear. Stapedial reflex was absent in the right ear, and results of other routine laboratory examinations such as complete blood count, urine analysis, liver function test, electrocardiogram, and chest radiograph were within normal limits. In the temporal bone computed tomography scan, soft tissue density that filled the right middle ear cavity and pushed the TM to the lateral side was identified (Fig 1). Additional soft tissue densities were observed in the tympanic isthmus and mastoid cavity. However, there was no evidence of ossicular destruction. With a presumed diagnosis of congenital cholesteatoma, a right tympanotomy was performed on May 6th, 1996. The mass within the
American Journal of Otolaryngology,Vo121, No 2 (March-April),2000: pp 127-130
127
128
HA, SHIN, AND YOON
Fig 1. Coronal view of a temporal bone CT. The middle ear cavity was filled with soft tissue density. The handle of malleus (arrow) was encircled by soft tissue mass, but no definite malleus destruction was observed.
Fig 3. Seromucinous glands (arrows) were admixed with mature adipose (A) and fibrous (F) tissues. All tissues could be observed in normal salivary glands. (Hematoxylin and eosin, original magnification × 100.)
middle ear cavity was exposed and was whitish and elastic in appearance (Fig 2). The mass appeared to be attached to the lateral portion of the middle ear, which resulted in the bulging appearance of the TM. It also seemed to extend anteriorly to the eustachian tube orifice and encircle the medial and lateral side of the malleus handle. The entire mass, including the part of the mass that was adhesive to the TM, was easily removed from the malleus handle without causing any injury to the ossicles and the chorda tympani nerve. The mass was found to be 10 × 5 × 3 m m in size, and the portion that extended to the eustachian tube orifice was elastic and yellowish. Canal-up mastoidectomy was performed, and good pneumatization of the air cells was observed. There were no other specific findings
noted with the exception of some mucosal swelling within the mastoid cavity. Good aeration between the middle ear and the mastoid was maintained. Histopathologic study revealed seromucinous glands, identified as histopathologically normal salivary gland tissue (Fig 3), mingled with some fat tissue and fibrous tissue. The patient was discharged without any complications on the 7th day after the operation. Postoperative impedance audiogram, pure-tone audiometry, and stapedial reflex test showed no change compared with preoperative data. At the patient's last visit, she was free of any symptoms. Physical examination showed no evidence of recurrence during a 36-month followup period. The patient is scheduled for another follow-up visit in 6 months.
Fig 2. Operative findings. After elevation of tympanomeatal flap, a mass (M) was found in the middle ear cavity. It was attached to the tympanic membrane and encircled the handle of the malleus (arrows), The mass was of a Iobulated nature and extended to the eustachian tube orifice. (A) Before removal of the mass (M). (B) After removal of the mass.
CHORISTOMA
DISCUSSION In the review of literature, 23 cases of middle ear cavity salivary choristoma have been reported. The distribution of patients was between the ages of 3 to 52, with a mean age of 17.5 and an approximate 1:2 male to female ratio. In 1961, Taylor and Martin 2 reported a case of a 31-year-old woman with unilateral conductive hearing loss. In this case, a mass within the middle ear cavity was observed during the physical examination, and although the mass was removed, temporary facial palsy was present as a complication of surgery. Operative findings showed that the mass was adjacent to the facial nerve, and an abnormality of the incus was also being observed. In 1962, Steffen and House 3 reported a case of a 51-year-old woman with similar s y m p t o m s and no definite abnormalities within the middle ear cavity. In 1984, Kartush and Graham 4 summarized 12 cases that had been reported up to that date. Based on intraoperative findings, they reported a high incidence of ossicle deformity associated with salivary gland choristoma of the middle ear. The incus was absent in 4 cases, and deformed incus was observed in 7 cases. In 5 other cases, there were no stapes, and deformed stapes were found in 6 other cases. In 1995, Namdar et al I summarized 20 cases with emphasis on the facial nerve abnormality and reported a total of 9 cases of exposed facial canal, 3 cases that showed abnormal course of the facial nerve, and 4 cases of postoperative facial palsy. Even though 3 patients experienced facial palsy only temporarily, in 1 case the patient became permanently paralyzed; thus, Namdar insisted on intraoperative monitoring of facial nerve in their practice. Although salivary gland choristoma usually seems to cause unilateral conductive hearing loss as its most common symptom, there have also been cases of bilateral hearing loss, 5,6 associated otorrhea and tinnitus, 2,7,8 and other cases with deformed external ear. 5,9 In the operative findings to date, there have been many cases of deformity found in the ossicles and/or facial nerve. Excluding those, there were also other cases associated with round w i n d o w obstruction, inner ear deformity, and mass lesions that had developed within the mastoid cavity. 5,6,9
129
In 1992, Gejas Mendez ~° reported on the youngest patient to date--is a 3-year-old girl with salivary gland choristoma and a dermoid cyst. The patient in our case was also a 3-yearold girl, who was the same age of the youngest patient among the cases reported to date. The patient was admitted with otalgia and otorrhea as the chief complaint and, although hearing disturbance was highly suspected, no evidence of malformation was found. Operative findings also showed no ossicle destruction and no other specific malformations except for the mass that encircled the handle of the malleus. Facial nerve was also observed in its normal route. Postoperatively, there was no complication, and outpatient-based followups have shown no evidence of recurrence of the disease thus far. Although the exact mechanism of the development of heterophic salivary gland in the middle ear has not yet been determined, according to the theory inspired by Patten, 22 the malformed expansion of the remnant parotid epithelium or pharyngeal endoderm appears to correspond with the salivary gland of the middle ear cavity. On the 4th month of the embryological period, malformations of the incus, stapes, and facial nerve may be accompanied by the embryological failure of the 2nd aortic arch. Usually, the disease develops at various ages in patients who show unilateral conductive hearing loss without TM perforation and whose middle ear cavity, under radiographic examination shows mass-like lesions that can be differentiated from glomus tumors, schwannomas, rhabdomyosarcomas, dermoid cysts, or other teratomas and lymphomas. Treatment principles consider conservative surgical removal of the mass before everything else because complete radical excision of the mass might cause facial palsy and, even if the mass is incompletely removed, no cases have been reported on recurrence or continuous growth of the mass to date. CONCLUSION Salivary gland choristoma is a rare disease that requires a differential diagnosis from other middle ear mass lesions that can cause unilateral conductive hearing loss. Choristoma is often associated with various other malforma-
130
tions. Malformation of the facial nerve occurs frequently enough to increase the possibility of facial nerve injury during surgery. To avoid this condition, caution is required. REFERENCE 1. Namdar I, Smouha EE, Kane P: Salivary gland choristoma of the middle ear: Role of intraoperative facial nerve monitoring. Otolaryngol Head Neck Surg 112:616-620, 1995 2. Taylor G, Martin H: Salivary gland tissue of the middle ear. Arch Otolaryngol 73:49-51, 1961 3. Steffen T, House W: Salivary gland choristoma of the middle ear. Arch Otolaryngol 76:74-75, 1962 4. Kartush JM, Graham MD: Salivary gland choristoma of the middle ear: A case report and review of the literature. Laryngoscope 94:228-230, 1984 5. Peron DL, Schuknecht HF: Congenital cholesteatoma with other anomalies. Arch Otolaryngol 101:498505, 1975 6. Wine CJ, Metcalf JE: Salivary gland choristoma of the middle ear and mastoid. Arch Otolaryngol 103:485-436, 1977 7. Hociota D, Ataman T: A case of salivary gland choristoma of the middle ear. J Laryngol Otol 89:10651068, 1975 8. Saeger KL, Gruskin P, Carberry JN: Salivary gland choristoma of the middle ear. Arch Pathol Lab Med 106:39-40, 1982 9. Caplingar CB, Hera JF: Middle ear choristoma with absent window: A report of one case. Arch Otolaryngol 85:39-40, 1967 10. Cejas Mendez DL: Choristoma of the salivary gland
HA, SHIN, AND YOON
and darmoid cyst of the middle ear in a 3-year-old girl. Apropos of a case. A n Otorrhinolaiyngol Ibero Am 19:275282, 1992 11. Noguara JT, Hasse RF: Congenital ossicular defects with a normal auditory canal: Its surgical treatment. Eye, Ear, Nose, Throat Monthly 43:37-39, 1964 12. Brunar RC: Salivary gland choristoma o f t h e m i d d l e ear: A case report. Arch Otolaryngol 91:303, 1970 13. Mischke RE, Brackmann DE, Gruskin P: Salivary gland choristoma of the middle ear. Arch Otolaryngol 103:432-434, 1977 14. Abadir WF, Pease WS: Salivary gland choristoma of the middle ear. l Laryngol Oto192:247-252, 1978 15. Kley HA: Monomorphous tubular salivary gland adenoma of the middle ear. Laryngol Rhinol 58:65-67, 1979 16. Cannon CR: Salivary gland choristoma of the middle ear. Am J Otol 1:250-251, 1980 17. Quaranta A, Mininni F, Resta L: Salivary gland choristoma of the middle ear: A case report. J Laryngol Oto195:953-956, 1981 18. Moore PJ, Benjamin BNP, Kan AE: Salivary gland choristoma of the middle ear. Int J Ped Otorhinolaryngol 8:91-95, 1984 19. Bottrill ID, Chawla OP, Ramsay AD: Salivary gland choristoma of the middle ear. J Laryngol Oto1106:630-632, 1992 20. Hinni ML, Beatty CW: Salivary gland choristoma of the middle ear: Report of a case and review of the literature. Ear Nose Throat J 75(7):422-424, 1996 21. A n d e r h u b e r W, Beham A, Walch C, et ah Choristoma of the middle ear. Eur Arch Otorhinolaryngol 253: 182-184, 1996 22. Patten BM: H u m a n embryology (ed 3). New York, NY: McGraw-Hill, 1968