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Epithelial migration in keratosis obturans
Epithelial
Migration
in Keratosis Obturans
Rogan John Corbridge, FRCS, Leslie Michaels, and Tony Wright, LLM, DM, FRCS
(Editorial Comment: The authors argue that keratosis obturans is a sequela of abnormal epithelial migration across the tympanic membrane and out the ear canal.)
Keratosis obturans is a rare condition in which a cholesteoma-like mass is found filling the deep external auditory meatus. It has been suggested that a fault in auditory epithelium migration is responsible for the accumulation of squamous debris, but no studies have been carried out to confirm this. We present two cases of keratosis obturans in which delayed and abnormal pathways of migration of epithelium of the tympanic membrane were discovered, indicating that a fault in auditory epithelium may indeed be the basis of this condition. CASE REPORTS Case 1 A ST-year-old woman presented as an emergency, complaining of acute severe left otalgia and hearing loss. She denied any previous ear problems other than one episode of wax impaction some years previously, which was treated by her general practitioner with aural syringing. On examination, the ear canal was found to be completely occluded with debris, Pure tone audiometry confirmed a conductive hearing loss, but the other ear was normal. She was treated over the next week with repeated aural toilet using the operating microscope and suction. It soon became evident that there was considerable erosion of the deep meatus. Computed tomography (CT) scan showed the left middle ear cavity to be entirely normal and air containing. However, there was bony expansion of the deep external ear canal with erosion of its superior walls (Fig 1). After complete removal of the debris, the ear canal was From The Professional Unit, The Royal National Throat, Nose, and Ear Hospital; the Department of Histopathology, and the Department of Otolaryngology, Institute of Laryngology and Otology, University College London, London, United Kingdom. Address reprint requests to Professor A. Wright, Institute of Laryngology and Otology, 330, Grays’ Inn Road, London WClX 8EE United Kingdom. Copyright 0 1996 by W.B. Saunders Company 0196-0709/96/l 706-0011$5.00/O American Journal of Otolatyngology,
Voll7,
MD, FRCPath,
found to be intact despite the marked bony expansion of the deep external auditory meatus. Both ear drums were then marked anterior and posterior to the malleus handle with a small drop of Bonney’s blue, a mixture of 1% crystal violet and 1% brilliant green solutions in 90% alcohol. This mixture is regularly used in dermatologic practice in the United Kingdom. Over the following 3 months, sequential photographs were taken of both ears at two weekly intervals using an otologic Hopkins red lens system (Karl Storz, Tuttlingen, Germany). Examination of the photographic records allowed us to compare the pathways and speed of migration of the dye markings on the two tympanic membranes. The migration in the unaffected ear showed the same normal pattern and speed as described by other investigators,’ moving radially outwards across the drum and then to the lateral end of the ear canal within 4 weeks. In the affected ear, however, the migration was significantly delayed; with the marker not even reaching the deep canal wall after z months. There was also an abnormal pattern of migration, with both the anterior and posterior markers moving in an anterior direction across the tympanic membrane and the posterior marker moving anteriorly over the malleus handle instead of posteriorly to the periphery (Fig 2). Case 2 A SO-year-old man originally presented 10 years earlier complaining of reduced hearing in the left ear. This had followed an acute left-sided otitis externa. On examination, the ear canal was found to be filled with thickened fibrous material, which was removed under general anesthesia to reveal an intact tympanic membrane. Some expansion of the deep meatus was noted. There was no keratin accumulation in the other ear, which appeared normal. Over the following years, the patient required regular aural toilet to remove a troublesome accumulation of keratin. At the time of our study, the ear had recently been cleaned and was normal in appearance. The tympanic membranes were marked using the same method as described in case 1. Once again, sequential photographs were taken and examined (Fig 3). In this case, the attic region was also marked with dye. This also showed a migratory pattern that was significantly delayed. In this case, however, the migration was in a downward fashion over the whole of the tympanic membrane, including the pars flaccida. The markers No 6 (November-December),
1996: pp 41 l-41 4
411
CORBRIDGE,
Fig 1. The coronal CT scans of case 1 show the normal right side and severe changes on the left side as indicated by the two arrows. The “cuts” have been taken at the level of the oval window and show that both middle ears and both attic regions are air filled. There is, however, major erosion of the bony floor of the left ear canal and some expansion of the roof with a thickening of soft tissues lining the ear canal.
moved from the attic to the pars tensa, which is the reverse of the normal sequence, and from here they continued inferiorly across the whole drum until they reached the annulus. Then they passed to the canal floor from whence they moved laterally out of the ear. Migration in the other ear was normal.
MICHAELS, AND WRIGHT
ther. It has been shown that there are two discrete pathways of migration in the normal ear drum.“J2 Zone 1 comprises a strip of epithelium on the malleus handle and pars flaccida. Markers placed over the malleus handle pass superiorly to the pars flaccida and then posterosuperiorly across the latter. Zone 2 comprises the epithelium over the remaining pars tensa, where movement is radial away from the malleus handle and towards the annulus. A condition of keratosis of the tympanic membrane has been described in which there is a progressive accumulation of keratin on the tympanic membrane. lo These ear drums displayed defects in the migratory patterns of the tympanic membrane epithelium. Two different abnormal patterns were seen: one in which
DISCUSSION The lesion of keratosis obturans was originally described by Toynbee2 in 1850, but the term “keratosis obturans” was first given to it by Wreden3 in 1874. The clinical manifestations are severe otalgia and hearing loss secondary to accumulation of large plugs of desquamated keratin in the ear canal.4 There may be a greatly widened bony ear canal with ballooning of its medial portion, often however, sparing the tympanic membranea A concurrence of keratosis obturans and bronchiectasis and/or sinusitis has been noted in 77% of juvenile cases but in only 20% of adult cases. Bilateral involvement is also more frequent in juveniles, whereas unilateral disease occurs primarily in adults. The etiology of this condition has remained uncertain, although it has been related to eczema, seborrhic dermatitis, or furunculosis,6~7 and even to bronchiectasis, leading to reflex sympathetic nervous system stimulation of ceruminal glands8 Faulty migration has often been suggested as the basis of this condition,4tgJ0 but until now, this remained unproven. Alberti showed that in normal subjects ink-dot markers on the tympanic membrane normally moved outward from the center of the ear drum and then laterally along the canal wall. Recently, this work has been taken fur-
Fig 2. Photographs of the migration studies carried out In case 1. The lateral process of the malleus is indicated by the designation “lp” and the umbo by “IL” (A) The Initial positions of the two dye markers are shown as a and b. (B) Position after 8 weeks. The dye marker “b” Is almost exactly overlylng the umbo.
EPITHELIAL
MIGRATION
IN KERATOSIS
413
OBTURANS
Fig 3. Photographs of the migration studies carried out in case 2. The lateral process of the malleus is indicated by the designation “lp” and the umbo by “u.” (A) The initial positions of the dye markers at a, b, and c. (B) Position after 8 weeks.
there was no migration at all and another in which there was an abnormally slow movement of epithelium combined with an abnormal migratory pathway. Here the epithelium was seen to move in an anterior direction across the whole drum. The latter defect is identical to that seen in case 1. It has been suggested that keratosis of the tympanic membrane may be a less severe form of keratosis obturans. Our findings in this case would support this view. In case 2, however, we discovered a previously undescribed abnormal migratory pathway. Here, the movement of the surface epithelium of the pars flaccida is reversed and migrates downwards to the pars tensa and from there moved inferiorly across the whole drum. To explain the abnormal migration in keratosis of the tympanic membrane, it has been suggested that there is an initiating inflammation, possibly viral, of the basal epithelial cells. It is these cells which are believed to be programmed for migratory activity. When regeneration takes place, the migratory activity of the whole restored tympanic membrane epithelium is defective.lO A comparable origin may account for the abnormal auditory epithelial migration that we have discovered in the presented cases of keratosis obturans. It is also possible that the presumed etiologic basis of this deep-seated external ear inflammation in keratosis obturans, namely viral infection, may be similar to that inflammation of the lower respiratory tract and paranasal sinus that so often accompany it.
CONCLUSION The migration studies we performed in the presented cases of acquired, adult-type keratosis obturans confirm that there is a major delay in epithelial migration on the affected side. We found a similar abnormal migratory pattern to that described in some cases of keratosis of the tympanic membrane.lO This lends weight to the argument that these two conditions may be in fact a spectrum of a single pathology rather than two separate entities. We have also discovered a new and bizarre pathological migratory pathway in a case of keratosis obturans. We suggest that damage to the basal epithelial layer of the tympanic membrane, which is a postulated etiologic factor in keratosis of the tympanic membrane, may also be important in the development of keratosis obturans in these patients. Observation of the auditory epithelial migration in further cases of keratosis obturans as well as in other conditions would be of interest.
REFERENCES 1. Michaels L, Soucek S: Stratified squamous epithelium of the tympanic membrane; its development and kinesis. Int J Pediatr Otolaryngol22:135-149,1991 2. Toynbee J: Specimens of molluscum contagiosum developed in the external auditory meatus. London Med Gaz 46:11,1850 3. Wreden R: A peculiar form of obstruction of the auditory meatus. Arch Ophthalmol Otolaryngol 4:261266,1874-1875
414
4. Piepergerdes JC, Kramer BM, Behnke EE: Keratosis obturans and external auditory canal cholesteatoma. Laryngoscope 90:383-390,198O 5. Bunting W: Ear canal cholesteatoma and bone absorption. Trans Am Acad Ophthalmol Otolaryngol72:161-172, 1968 6. Green LD: Cholesteatoma-like accumulations in the external auditory meatus. Arch Otolaryngol18:161-167,1933 7. McKibben BG: Cholesteatoma-like accumulations in the external auditory meatus. Arch Otolaryngol 67:626628,1958 8. Morrison AW: Keratosis obturans. J Laryngol Otolaryngol70:317-321,1956
CORBRIDGE, MICHAELS, AND WRIGHT
9. Alberti PWRh4: Epithelial migration on the tympanic membrane. J Laryngol 78:808-830,1964 10. Soucek S, Michaels L: Keratosis of the tympanic membrane and deep external auditory canal. Eur Arch Otorhino laryngol250:140-142,1993 11. Michaels L, Soucek S: Auditory epithelial migration on the human tympanic membrane: II. The existence of two discrete migratory pathways and their embryologic correlates. Am J Anatomy 189:189-200,199O 12. Michaels L, Soucek S: Development of the stratified squamous epithelium of the human tympanic membrane and external canal: The origin of auditory epithelial migration. Am J Anatomy 184:334-344,1989
Migration
in Keratosis Obturans
Rogan John Corbridge, FRCS, Leslie Michaels, and Tony Wright, LLM, DM, FRCS
(Editorial Comment: The authors argue that keratosis obturans is a sequela of abnormal epithelial migration across the tympanic membrane and out the ear canal.)
Keratosis obturans is a rare condition in which a cholesteoma-like mass is found filling the deep external auditory meatus. It has been suggested that a fault in auditory epithelium migration is responsible for the accumulation of squamous debris, but no studies have been carried out to confirm this. We present two cases of keratosis obturans in which delayed and abnormal pathways of migration of epithelium of the tympanic membrane were discovered, indicating that a fault in auditory epithelium may indeed be the basis of this condition. CASE REPORTS Case 1 A ST-year-old woman presented as an emergency, complaining of acute severe left otalgia and hearing loss. She denied any previous ear problems other than one episode of wax impaction some years previously, which was treated by her general practitioner with aural syringing. On examination, the ear canal was found to be completely occluded with debris, Pure tone audiometry confirmed a conductive hearing loss, but the other ear was normal. She was treated over the next week with repeated aural toilet using the operating microscope and suction. It soon became evident that there was considerable erosion of the deep meatus. Computed tomography (CT) scan showed the left middle ear cavity to be entirely normal and air containing. However, there was bony expansion of the deep external ear canal with erosion of its superior walls (Fig 1). After complete removal of the debris, the ear canal was From The Professional Unit, The Royal National Throat, Nose, and Ear Hospital; the Department of Histopathology, and the Department of Otolaryngology, Institute of Laryngology and Otology, University College London, London, United Kingdom. Address reprint requests to Professor A. Wright, Institute of Laryngology and Otology, 330, Grays’ Inn Road, London WClX 8EE United Kingdom. Copyright 0 1996 by W.B. Saunders Company 0196-0709/96/l 706-0011$5.00/O American Journal of Otolatyngology,
Voll7,
MD, FRCPath,
found to be intact despite the marked bony expansion of the deep external auditory meatus. Both ear drums were then marked anterior and posterior to the malleus handle with a small drop of Bonney’s blue, a mixture of 1% crystal violet and 1% brilliant green solutions in 90% alcohol. This mixture is regularly used in dermatologic practice in the United Kingdom. Over the following 3 months, sequential photographs were taken of both ears at two weekly intervals using an otologic Hopkins red lens system (Karl Storz, Tuttlingen, Germany). Examination of the photographic records allowed us to compare the pathways and speed of migration of the dye markings on the two tympanic membranes. The migration in the unaffected ear showed the same normal pattern and speed as described by other investigators,’ moving radially outwards across the drum and then to the lateral end of the ear canal within 4 weeks. In the affected ear, however, the migration was significantly delayed; with the marker not even reaching the deep canal wall after z months. There was also an abnormal pattern of migration, with both the anterior and posterior markers moving in an anterior direction across the tympanic membrane and the posterior marker moving anteriorly over the malleus handle instead of posteriorly to the periphery (Fig 2). Case 2 A SO-year-old man originally presented 10 years earlier complaining of reduced hearing in the left ear. This had followed an acute left-sided otitis externa. On examination, the ear canal was found to be filled with thickened fibrous material, which was removed under general anesthesia to reveal an intact tympanic membrane. Some expansion of the deep meatus was noted. There was no keratin accumulation in the other ear, which appeared normal. Over the following years, the patient required regular aural toilet to remove a troublesome accumulation of keratin. At the time of our study, the ear had recently been cleaned and was normal in appearance. The tympanic membranes were marked using the same method as described in case 1. Once again, sequential photographs were taken and examined (Fig 3). In this case, the attic region was also marked with dye. This also showed a migratory pattern that was significantly delayed. In this case, however, the migration was in a downward fashion over the whole of the tympanic membrane, including the pars flaccida. The markers No 6 (November-December),
1996: pp 41 l-41 4
411
CORBRIDGE,
Fig 1. The coronal CT scans of case 1 show the normal right side and severe changes on the left side as indicated by the two arrows. The “cuts” have been taken at the level of the oval window and show that both middle ears and both attic regions are air filled. There is, however, major erosion of the bony floor of the left ear canal and some expansion of the roof with a thickening of soft tissues lining the ear canal.
moved from the attic to the pars tensa, which is the reverse of the normal sequence, and from here they continued inferiorly across the whole drum until they reached the annulus. Then they passed to the canal floor from whence they moved laterally out of the ear. Migration in the other ear was normal.
MICHAELS, AND WRIGHT
ther. It has been shown that there are two discrete pathways of migration in the normal ear drum.“J2 Zone 1 comprises a strip of epithelium on the malleus handle and pars flaccida. Markers placed over the malleus handle pass superiorly to the pars flaccida and then posterosuperiorly across the latter. Zone 2 comprises the epithelium over the remaining pars tensa, where movement is radial away from the malleus handle and towards the annulus. A condition of keratosis of the tympanic membrane has been described in which there is a progressive accumulation of keratin on the tympanic membrane. lo These ear drums displayed defects in the migratory patterns of the tympanic membrane epithelium. Two different abnormal patterns were seen: one in which
DISCUSSION The lesion of keratosis obturans was originally described by Toynbee2 in 1850, but the term “keratosis obturans” was first given to it by Wreden3 in 1874. The clinical manifestations are severe otalgia and hearing loss secondary to accumulation of large plugs of desquamated keratin in the ear canal.4 There may be a greatly widened bony ear canal with ballooning of its medial portion, often however, sparing the tympanic membranea A concurrence of keratosis obturans and bronchiectasis and/or sinusitis has been noted in 77% of juvenile cases but in only 20% of adult cases. Bilateral involvement is also more frequent in juveniles, whereas unilateral disease occurs primarily in adults. The etiology of this condition has remained uncertain, although it has been related to eczema, seborrhic dermatitis, or furunculosis,6~7 and even to bronchiectasis, leading to reflex sympathetic nervous system stimulation of ceruminal glands8 Faulty migration has often been suggested as the basis of this condition,4tgJ0 but until now, this remained unproven. Alberti showed that in normal subjects ink-dot markers on the tympanic membrane normally moved outward from the center of the ear drum and then laterally along the canal wall. Recently, this work has been taken fur-
Fig 2. Photographs of the migration studies carried out In case 1. The lateral process of the malleus is indicated by the designation “lp” and the umbo by “IL” (A) The Initial positions of the two dye markers are shown as a and b. (B) Position after 8 weeks. The dye marker “b” Is almost exactly overlylng the umbo.
EPITHELIAL
MIGRATION
IN KERATOSIS
413
OBTURANS
Fig 3. Photographs of the migration studies carried out in case 2. The lateral process of the malleus is indicated by the designation “lp” and the umbo by “u.” (A) The initial positions of the dye markers at a, b, and c. (B) Position after 8 weeks.
there was no migration at all and another in which there was an abnormally slow movement of epithelium combined with an abnormal migratory pathway. Here the epithelium was seen to move in an anterior direction across the whole drum. The latter defect is identical to that seen in case 1. It has been suggested that keratosis of the tympanic membrane may be a less severe form of keratosis obturans. Our findings in this case would support this view. In case 2, however, we discovered a previously undescribed abnormal migratory pathway. Here, the movement of the surface epithelium of the pars flaccida is reversed and migrates downwards to the pars tensa and from there moved inferiorly across the whole drum. To explain the abnormal migration in keratosis of the tympanic membrane, it has been suggested that there is an initiating inflammation, possibly viral, of the basal epithelial cells. It is these cells which are believed to be programmed for migratory activity. When regeneration takes place, the migratory activity of the whole restored tympanic membrane epithelium is defective.lO A comparable origin may account for the abnormal auditory epithelial migration that we have discovered in the presented cases of keratosis obturans. It is also possible that the presumed etiologic basis of this deep-seated external ear inflammation in keratosis obturans, namely viral infection, may be similar to that inflammation of the lower respiratory tract and paranasal sinus that so often accompany it.
CONCLUSION The migration studies we performed in the presented cases of acquired, adult-type keratosis obturans confirm that there is a major delay in epithelial migration on the affected side. We found a similar abnormal migratory pattern to that described in some cases of keratosis of the tympanic membrane.lO This lends weight to the argument that these two conditions may be in fact a spectrum of a single pathology rather than two separate entities. We have also discovered a new and bizarre pathological migratory pathway in a case of keratosis obturans. We suggest that damage to the basal epithelial layer of the tympanic membrane, which is a postulated etiologic factor in keratosis of the tympanic membrane, may also be important in the development of keratosis obturans in these patients. Observation of the auditory epithelial migration in further cases of keratosis obturans as well as in other conditions would be of interest.
REFERENCES 1. Michaels L, Soucek S: Stratified squamous epithelium of the tympanic membrane; its development and kinesis. Int J Pediatr Otolaryngol22:135-149,1991 2. Toynbee J: Specimens of molluscum contagiosum developed in the external auditory meatus. London Med Gaz 46:11,1850 3. Wreden R: A peculiar form of obstruction of the auditory meatus. Arch Ophthalmol Otolaryngol 4:261266,1874-1875
414
4. Piepergerdes JC, Kramer BM, Behnke EE: Keratosis obturans and external auditory canal cholesteatoma. Laryngoscope 90:383-390,198O 5. Bunting W: Ear canal cholesteatoma and bone absorption. Trans Am Acad Ophthalmol Otolaryngol72:161-172, 1968 6. Green LD: Cholesteatoma-like accumulations in the external auditory meatus. Arch Otolaryngol18:161-167,1933 7. McKibben BG: Cholesteatoma-like accumulations in the external auditory meatus. Arch Otolaryngol 67:626628,1958 8. Morrison AW: Keratosis obturans. J Laryngol Otolaryngol70:317-321,1956
CORBRIDGE, MICHAELS, AND WRIGHT
9. Alberti PWRh4: Epithelial migration on the tympanic membrane. J Laryngol 78:808-830,1964 10. Soucek S, Michaels L: Keratosis of the tympanic membrane and deep external auditory canal. Eur Arch Otorhino laryngol250:140-142,1993 11. Michaels L, Soucek S: Auditory epithelial migration on the human tympanic membrane: II. The existence of two discrete migratory pathways and their embryologic correlates. Am J Anatomy 189:189-200,199O 12. Michaels L, Soucek S: Development of the stratified squamous epithelium of the human tympanic membrane and external canal: The origin of auditory epithelial migration. Am J Anatomy 184:334-344,1989