Clinical records Bilateral symmetrical maldevelopment of the external ear and middle-ear cleft with pharyngeal and soft palate defects A.
GNANAPRAGASAM
(Kuala Lumpur)
DEFECTS in the development of the first and second branchial arches have been well documented under various descriptions: mandibulo-facial dysostosis, bilateral facial agenesis, multiple facial abnormalities, etc. The most widely recognized one is the Treacher-Collins or Franceschetti-Zwahlen Syndrome, a condition first described by Barry of Edinburgh in 1889. However, developmental abnormality of the first and second arches resulting in external ear, middle ear and pharyngeal defects is rare. A number of cases of bilateral symmetrical defects of the pharyngeal structures associated with other abnormalities such as absence of one or more palatine tonsils and preauricular fistulae have been reported (Gorlin and Pindorg, 1964). These are few and far between, and there is only one reference to pharyngeal abnormality with deafness in the literature (Chiari, 1884). The author believes the following case report to be a rare combination of branchial arch defect.
Case report
C.S.F., female aged 8 years, presented with absent pinna and external auditory canal on both sides, deafness and abnormal speech. She is the youngest in the family of ten, with a normal pre-, peri-, and post-natal history. Her milestones were noimal except for marked deafness and defective articulation. All the other children are apparently normal. On examination there is complete absence of both pinnae and both external auditory canals, with a dimple on either side about the middle of the posterior border of the ramus of the mandible (Figs. 1 and 2). The mastoid processes are small, and the temporo-mandibular joints are normal. Air conduction using a tuning fork was absent on both sides, but bone conduction over the mastoid tips was normal. The Weber was central, and loud speech was heard at a distance of two feet from either side of the head. The facial bones are normally developed. The hard palate is intact; the soft palate is small, thin and asymmetrical, with marked deficiency on the left side and a bifid uvula. Its movement is impaired especially on the right side. The anterior two-thirds of the tongue are normal, the left half of the posterior third of the tongue is hypertrophied. The right anterior pillar, the left posterior pillar and the palatine tonsils are absent. The lateral pharyngeal walls posterior to the pillars are deficient. The Eustachian tube openings are absent except 845
oo
FIG. I.
Front view of patient showing bilateral absence of pinna.
FIG. 2. Kight lateral view —showing absent pinna and external auditory canal.
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Clinical records for a rudimentary tubercle on either side. The velo-pharyng°al space is abnormally large. The nasopharynx and oropharynx are devoid ot lymphoid tissue (Figs. 3 and 4). The opening and movement of the mouth are normal. Investigation Radiological examination of the paranasal sinuses was normal. The temporal bones showed absence of air cells, middle-ear cleft and external auditory meatus. The internal auditory meatuses were both intact and normal. The skull and facial bones showed no abnormalities. Tomogram of the petrous temporal bone confirmed absence of the external auditory canals and the middle-ear structures. The audiogram showed normal bone conduction. Air conduction could not be done (Fig. 5). Speech and hearing assessment revealed that her language ability and vocabulary were just below her age group and her ability to lip read and use visual cues were excellent. Her speech was frequently unintelligible with marked nasal escape. Discussion The combination of defects in this patient are obvious defects in first-and second-arch development. However, it does not fit into the well recognized arch syndromes described by Franceschetti and Klein (1949). To understand this defect, a brief reference is made to the embryology and anatomy of this region. During early foetal development a series of six arches appear on the lateral aspect of the head. The auricle develops as six cartilaginous tubercles towards the end of the first foetal month; three from the first arch and three from the second arch. They fuse to form the auricle. The external auditory canal is formed from the ectoderm of the first vesceral cleft. The primary external auditory canal is a funnel-shaped tube from which the cartilaginous meatus and a small portion of the bony canal is formed. From this tube a solid core of epithelium extends inwards, but this core eventually hollows out to form the inner part of the external auditory canal (the so-called secondary meatus), the blind end of which forms the outer epidermal layer of the tympanic membrane. The middle layer of this membrane is formed from the mesoderm between the first visceral arch and the tubo-tympanic recess, while the inner mucosal layer is derived from a part of the latter recess (Edwards, W. G., in Scott-Brown, 1971).
The middle ear cleft including the aditus, the antrum and the Eustachian tube is developed from the entoderm of the tubo-tympanic recess which is pushed out from the dorsal part of the first and second pharyngeal pouch together with the adjacent pharyngeal wall, to approach the surface between the fiist and second visceral arches. The ossicles begin to be defined at the eighth foetal week. The malleus and incus are derived from the mesenchyme of the first visceral arch (Meckel's cartilage), while the mesoderm of the second visceral arch gives rise to the head, neck and crura of the stapes, the foot plate being derived from the otic capsule (Cauldwell and Anson, 1942). The pharyngeal grooves give rise to a series of structures. Each groove divides into a ventral and a dorsal pouch. The dorsal pouch of the first and second arches gives rise to the Eustachian tube, etc. The tubal (pharyngeal) 847
00
oo
FIG. 3. Left half of oropharynx. Note bifid uvula, thin soft palate, absent tonsils and palato pharyngeal fold, with deficient lateral pharyngeal wall.
FIG. 4. Right half of oropharynx. Note the thin soft palate with absent oalato-clossal fold, tonsils and deficient lateral Dharvneeal wall.
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BONE CONDUCTION AUDIOGRAM
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A. Gnanapragasam tonsils arise as aggregations of mesenchymal cells around the Eustachian tube which later become invaded by lymphocytes. The palatine tonsils or 'The tonsils' are developed in the ventral portion of the second pouch during the fourth month, as a hypoplastic recess. This opens into the pharynx as a funnelshaped cavity and terminates under cover of the soft palate as a narrow channel. The outer wall of this hypoblastic tube is invaded by lymphocytes (St. Clair Thomson and Negus, 1948). The faucial pillars represent portions of the second and third branchial arches. While the arches differentiate into various structures, the primitive foregut comes to lie dorsal to the developing heart tube, towards the end of the fourth week. Its anterior end at this stage is shut off by the bucco-pharyngeal membrane. This membrane ruptures and the ectodermally-lined stomatodeaum becomes continuous with the foregut. This new foregut once established differentiates with the development of the septum, the hard palate and the tongue, into the nasal, oral and pharyngeal regions. The fully developed soft palate consists of muscles with their aponeuroses, the main muscles being the levator palati, tensor palati, palato-glossus, palatopharyngeus and musculus uvulae. In this patient the defect is the result of maldevelopment in both the first and second arches as well as in the foregut. The arch defect seems to be confined to the external ear and middle-ear cleft without involving the facio-mandibular component. The clinical, radiological and audiologicalfindingssuggest complete agenesis of the middle-ear cleft. In addition the pharyngeal pouches that take part in the normal development of the nasopharynx and oropharynx are also affected and their derivatives (namely, the lateral pharyngeal walls, mucosal folds and muscles, especially palato-glossus and palato-pharyngeus, and the lymphoid tissues) are absent. This has resulted in an abnormally large nasopharynx and oropharynx with an incompetent velo-pharyngeal sphincter. The soft palate which plays an important part in this sphinctric mechanism is defective due to poorly developed muscles, especially the levator palati and tensor palati. These two muscles have part of their origin from the cartilagenous and bony parts of the Eustachian tube and, the latter being rudimentary in this patient, these muscles have lost their mechanical advantage. The clinical features, though consistent with first and second arch developmental abnormality, do not have all the stigmata of the Treacher-Collins Syndrome. The parents, grandparents, brothers and sisters all are apparently normal. The defect may be the result of a possible peri-gestational damage to the embryo in the first trimester from infection via the placenta, or interference with the vascular supply, to this region. McKenzie and Craig (1955) reviewing the embryology of the first and second visceral arches with particular reference to their vascular supply, stressed the hazardous existence of this region from the third to the fifth week of gestation. During this period, this region is dependant on the relay of blood via three successive vessels—the remains of the first aortic arch; the stapedial artery with its branches; and the external carotid artery—each of which in turn takes over the dominant supply. These early vascular changes, causing absolute or relative ischaemia to the highly active embryonic tissue, may result in complete chaos to subsequent development. The defects in this patient have severely affected the development of 850
Clinical records speech and hearing. The absence of clinical and radiological evidence of the pinna, external auditory canal and middle-ear cleft makes operative reconstruction of the external canal and middle-ear cavity a formidable and hazardous procedure. However, Livingstone (1964) for various reasons advocates early bony surgery, at least on one side, by the age of 2 years, in bilateral cases. With a hearing aid of the bone-conductor type placed over the mastoid and intensive speech training the patient has been able to improve both her vocabulary and speech to such an extent that it has enabled her to be placed in a normal school. Summary An unusual combination of first and second arch anomalies is presented. This has resulted in absent middle and external ears with gross naso- and oropharyngeal defects. A brief reference is made to the embryology of this region to explain the anatomical and functional defects. Vascular abnormality during the peri-gestational period is suggested as a possible cause and a conservative line of treatment has been followed with good result. Acknowledgement I wish to thank the Head, Department of Radiology, for allowing me to print the X-rays; the Medical Illustration Unit, for photographic assistance; and Miss A. M. Tan, for secretarial assistance. REFERENCES CAULDWELL, E. W., and ANSON, B. J. (1942) Archives of Otolaryngology, 36, £91. CHIARI, O. (1884) Monatsschrift fur Ohrenheikunde und Laryngo-Rhinologie, 18, 141. EDWARDS, W. G. (1971) In: Scott-Brown's Diseases of the Ear, Nose and Throat. Butterworth & Co. (Publishers) Ltd., 3rd edition, volume 2, p. 51. FRANCESCHETTI, A., and KLEIN, D. (1949) Ada Ophthalmologica, 27, 143.
GORLIN, P. J., and PINDBORG, J. J. (1964) Syndromes of the Head and Neck, McGrawHill Inc., p. 228. HAMILTON, W. J., and HARRISON, R. J. (1971) In: Scott-Brown's Diseases of the Ear, Nose and Throat. Butterworth & Co. (Publishers) Ltd., 3rd edition, volume 1, p. 189. LIVINGSTONE, G. (1964) Proceedings of The Royal Society of Medicine, 57, 1176. MARAN, A. G. (1964) Journal of Laryngology and Otology, 78, 135. MCKENZIE, J., and CRAIG, J. (1955) Archives of Diseases of Childhood, 30, 391. ST. CLAIR THOMSON, and NEGUS, V. E. (1948) Diseases of the Nose and Throat. Cassell and Co. Ltd., 5th edition, p. 406. Department of Otorhinolaryngology, Faculty of Medicine University of Malaya, KUALA LUMPUR, Malaysia.
851
GNANAPRAGASAM
(Kuala Lumpur)
DEFECTS in the development of the first and second branchial arches have been well documented under various descriptions: mandibulo-facial dysostosis, bilateral facial agenesis, multiple facial abnormalities, etc. The most widely recognized one is the Treacher-Collins or Franceschetti-Zwahlen Syndrome, a condition first described by Barry of Edinburgh in 1889. However, developmental abnormality of the first and second arches resulting in external ear, middle ear and pharyngeal defects is rare. A number of cases of bilateral symmetrical defects of the pharyngeal structures associated with other abnormalities such as absence of one or more palatine tonsils and preauricular fistulae have been reported (Gorlin and Pindorg, 1964). These are few and far between, and there is only one reference to pharyngeal abnormality with deafness in the literature (Chiari, 1884). The author believes the following case report to be a rare combination of branchial arch defect.
Case report
C.S.F., female aged 8 years, presented with absent pinna and external auditory canal on both sides, deafness and abnormal speech. She is the youngest in the family of ten, with a normal pre-, peri-, and post-natal history. Her milestones were noimal except for marked deafness and defective articulation. All the other children are apparently normal. On examination there is complete absence of both pinnae and both external auditory canals, with a dimple on either side about the middle of the posterior border of the ramus of the mandible (Figs. 1 and 2). The mastoid processes are small, and the temporo-mandibular joints are normal. Air conduction using a tuning fork was absent on both sides, but bone conduction over the mastoid tips was normal. The Weber was central, and loud speech was heard at a distance of two feet from either side of the head. The facial bones are normally developed. The hard palate is intact; the soft palate is small, thin and asymmetrical, with marked deficiency on the left side and a bifid uvula. Its movement is impaired especially on the right side. The anterior two-thirds of the tongue are normal, the left half of the posterior third of the tongue is hypertrophied. The right anterior pillar, the left posterior pillar and the palatine tonsils are absent. The lateral pharyngeal walls posterior to the pillars are deficient. The Eustachian tube openings are absent except 845
oo
FIG. I.
Front view of patient showing bilateral absence of pinna.
FIG. 2. Kight lateral view —showing absent pinna and external auditory canal.
3
P
On
crq
P
i-i
p
p
o
Clinical records for a rudimentary tubercle on either side. The velo-pharyng°al space is abnormally large. The nasopharynx and oropharynx are devoid ot lymphoid tissue (Figs. 3 and 4). The opening and movement of the mouth are normal. Investigation Radiological examination of the paranasal sinuses was normal. The temporal bones showed absence of air cells, middle-ear cleft and external auditory meatus. The internal auditory meatuses were both intact and normal. The skull and facial bones showed no abnormalities. Tomogram of the petrous temporal bone confirmed absence of the external auditory canals and the middle-ear structures. The audiogram showed normal bone conduction. Air conduction could not be done (Fig. 5). Speech and hearing assessment revealed that her language ability and vocabulary were just below her age group and her ability to lip read and use visual cues were excellent. Her speech was frequently unintelligible with marked nasal escape. Discussion The combination of defects in this patient are obvious defects in first-and second-arch development. However, it does not fit into the well recognized arch syndromes described by Franceschetti and Klein (1949). To understand this defect, a brief reference is made to the embryology and anatomy of this region. During early foetal development a series of six arches appear on the lateral aspect of the head. The auricle develops as six cartilaginous tubercles towards the end of the first foetal month; three from the first arch and three from the second arch. They fuse to form the auricle. The external auditory canal is formed from the ectoderm of the first vesceral cleft. The primary external auditory canal is a funnel-shaped tube from which the cartilaginous meatus and a small portion of the bony canal is formed. From this tube a solid core of epithelium extends inwards, but this core eventually hollows out to form the inner part of the external auditory canal (the so-called secondary meatus), the blind end of which forms the outer epidermal layer of the tympanic membrane. The middle layer of this membrane is formed from the mesoderm between the first visceral arch and the tubo-tympanic recess, while the inner mucosal layer is derived from a part of the latter recess (Edwards, W. G., in Scott-Brown, 1971).
The middle ear cleft including the aditus, the antrum and the Eustachian tube is developed from the entoderm of the tubo-tympanic recess which is pushed out from the dorsal part of the first and second pharyngeal pouch together with the adjacent pharyngeal wall, to approach the surface between the fiist and second visceral arches. The ossicles begin to be defined at the eighth foetal week. The malleus and incus are derived from the mesenchyme of the first visceral arch (Meckel's cartilage), while the mesoderm of the second visceral arch gives rise to the head, neck and crura of the stapes, the foot plate being derived from the otic capsule (Cauldwell and Anson, 1942). The pharyngeal grooves give rise to a series of structures. Each groove divides into a ventral and a dorsal pouch. The dorsal pouch of the first and second arches gives rise to the Eustachian tube, etc. The tubal (pharyngeal) 847
00
oo
FIG. 3. Left half of oropharynx. Note bifid uvula, thin soft palate, absent tonsils and palato pharyngeal fold, with deficient lateral pharyngeal wall.
FIG. 4. Right half of oropharynx. Note the thin soft palate with absent oalato-clossal fold, tonsils and deficient lateral Dharvneeal wall.
3
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P
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P
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Loss
Hearii
M96^ % 5792; 115*4
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S
S12
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256
LEFT
FIG.
5.
BONE CONDUCTION AUDIOGRAM
Db
110
80 90 y
40
30
100 \ •
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jji
.£
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100 1446
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RIGHT
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n
Q 3'
A. Gnanapragasam tonsils arise as aggregations of mesenchymal cells around the Eustachian tube which later become invaded by lymphocytes. The palatine tonsils or 'The tonsils' are developed in the ventral portion of the second pouch during the fourth month, as a hypoplastic recess. This opens into the pharynx as a funnelshaped cavity and terminates under cover of the soft palate as a narrow channel. The outer wall of this hypoblastic tube is invaded by lymphocytes (St. Clair Thomson and Negus, 1948). The faucial pillars represent portions of the second and third branchial arches. While the arches differentiate into various structures, the primitive foregut comes to lie dorsal to the developing heart tube, towards the end of the fourth week. Its anterior end at this stage is shut off by the bucco-pharyngeal membrane. This membrane ruptures and the ectodermally-lined stomatodeaum becomes continuous with the foregut. This new foregut once established differentiates with the development of the septum, the hard palate and the tongue, into the nasal, oral and pharyngeal regions. The fully developed soft palate consists of muscles with their aponeuroses, the main muscles being the levator palati, tensor palati, palato-glossus, palatopharyngeus and musculus uvulae. In this patient the defect is the result of maldevelopment in both the first and second arches as well as in the foregut. The arch defect seems to be confined to the external ear and middle-ear cleft without involving the facio-mandibular component. The clinical, radiological and audiologicalfindingssuggest complete agenesis of the middle-ear cleft. In addition the pharyngeal pouches that take part in the normal development of the nasopharynx and oropharynx are also affected and their derivatives (namely, the lateral pharyngeal walls, mucosal folds and muscles, especially palato-glossus and palato-pharyngeus, and the lymphoid tissues) are absent. This has resulted in an abnormally large nasopharynx and oropharynx with an incompetent velo-pharyngeal sphincter. The soft palate which plays an important part in this sphinctric mechanism is defective due to poorly developed muscles, especially the levator palati and tensor palati. These two muscles have part of their origin from the cartilagenous and bony parts of the Eustachian tube and, the latter being rudimentary in this patient, these muscles have lost their mechanical advantage. The clinical features, though consistent with first and second arch developmental abnormality, do not have all the stigmata of the Treacher-Collins Syndrome. The parents, grandparents, brothers and sisters all are apparently normal. The defect may be the result of a possible peri-gestational damage to the embryo in the first trimester from infection via the placenta, or interference with the vascular supply, to this region. McKenzie and Craig (1955) reviewing the embryology of the first and second visceral arches with particular reference to their vascular supply, stressed the hazardous existence of this region from the third to the fifth week of gestation. During this period, this region is dependant on the relay of blood via three successive vessels—the remains of the first aortic arch; the stapedial artery with its branches; and the external carotid artery—each of which in turn takes over the dominant supply. These early vascular changes, causing absolute or relative ischaemia to the highly active embryonic tissue, may result in complete chaos to subsequent development. The defects in this patient have severely affected the development of 850
Clinical records speech and hearing. The absence of clinical and radiological evidence of the pinna, external auditory canal and middle-ear cleft makes operative reconstruction of the external canal and middle-ear cavity a formidable and hazardous procedure. However, Livingstone (1964) for various reasons advocates early bony surgery, at least on one side, by the age of 2 years, in bilateral cases. With a hearing aid of the bone-conductor type placed over the mastoid and intensive speech training the patient has been able to improve both her vocabulary and speech to such an extent that it has enabled her to be placed in a normal school. Summary An unusual combination of first and second arch anomalies is presented. This has resulted in absent middle and external ears with gross naso- and oropharyngeal defects. A brief reference is made to the embryology of this region to explain the anatomical and functional defects. Vascular abnormality during the peri-gestational period is suggested as a possible cause and a conservative line of treatment has been followed with good result. Acknowledgement I wish to thank the Head, Department of Radiology, for allowing me to print the X-rays; the Medical Illustration Unit, for photographic assistance; and Miss A. M. Tan, for secretarial assistance. REFERENCES CAULDWELL, E. W., and ANSON, B. J. (1942) Archives of Otolaryngology, 36, £91. CHIARI, O. (1884) Monatsschrift fur Ohrenheikunde und Laryngo-Rhinologie, 18, 141. EDWARDS, W. G. (1971) In: Scott-Brown's Diseases of the Ear, Nose and Throat. Butterworth & Co. (Publishers) Ltd., 3rd edition, volume 2, p. 51. FRANCESCHETTI, A., and KLEIN, D. (1949) Ada Ophthalmologica, 27, 143.
GORLIN, P. J., and PINDBORG, J. J. (1964) Syndromes of the Head and Neck, McGrawHill Inc., p. 228. HAMILTON, W. J., and HARRISON, R. J. (1971) In: Scott-Brown's Diseases of the Ear, Nose and Throat. Butterworth & Co. (Publishers) Ltd., 3rd edition, volume 1, p. 189. LIVINGSTONE, G. (1964) Proceedings of The Royal Society of Medicine, 57, 1176. MARAN, A. G. (1964) Journal of Laryngology and Otology, 78, 135. MCKENZIE, J., and CRAIG, J. (1955) Archives of Diseases of Childhood, 30, 391. ST. CLAIR THOMSON, and NEGUS, V. E. (1948) Diseases of the Nose and Throat. Cassell and Co. Ltd., 5th edition, p. 406. Department of Otorhinolaryngology, Faculty of Medicine University of Malaya, KUALA LUMPUR, Malaysia.
851
