Aust Paedratr. J. (1979), 15'275-277
Aplasia of the First and Second Branchial Arches
K. Y . WOON: and K . L. TAN2
Department of Paediatrics, University of Singapore, Singapore
Woon, K. Y. and Tan, K. L. (1979). Aust. Paediatr. J., 15, 275-277. Aplasia of the first and second branchial arches. A Case with the very rare syndrome of otocephaly is reported. It is possible to diagnose this condition in-utero by radiography. Since this is a lethal condition, remedial action can be taken in early pregnancy.
The very severe form of aplasia of the first and second branchial arches is represented in the syndrome of otocephaly which is invariably fatal.
CASE REPORT A 21-year-old female was admitted at 32 weeks' gestation for suspected intrauterine death. Her first pregnancy had been normal, resulting in the delivery of a healthy baby. On examination there was obvious hydramnios; the size of the abdomen was consistent with 36 weeks' gestation, and regular fetal heart sounds were audible. An abdominal X-ray of the mother was taken ar?d at that time interpreted as normal by the obstetrician (Fig. 1). She was admitted one month later in labour with leaking blood-stained liquor. The infant was delivered by forceps for fetal distress; the baby was abnormal and died one hour later. The appearance of the infant (birth weight 1375 gm, length 41 cm) is shown in Figure 2. There was an antimongoloid slant to the palpebral fissures with absent eye-lashes and eye-brows. The mouth was only a tiny central stoma with the mandibles conspicuously absent (Fig. 3). The most obvious features were the pinnae which were attached to the neck just below the head; their configuration was, however. fairly normal. The tongue was hypoplastic and the oral cavity very small. The penis was normal externally but the testes were impalpable. The limbs appeared to be normal. Autopsy demonstrated that the mandibles were absent; the thyroid, parathyroid and thymus were apparently normal. The testes were retro-peritoneal. Both the trachea and oesophagus appeared to be normal. Histology demonstrated a small focus of eosinophils in the epicardium near the apex of the heart. The lungs were 1 Senior Registrar Neonatal Unit 2 Associate Professor Department o f Paediatrics University of Singapore Head Neonatal Unit Kandang Kerbau Hospital
Received Janbary 25 1979
Figure 1. Abnormal X-ray of foetus which was interpreted as "normal". Note the absence of the mandibles.
276
AUSTRALIAN PAEDlATRlC JOURNAL
theory that the primordia for the maxillary processes are derived from mesenchyme which migrates from the ventral neural crest to form portions of the base of the skull and maxilla (Keen, 1955; Altman, 1957). The pathogenesis of this condition has been attributed to intrauterine facial necrosis due to failure of development of the stapedial artery (Keith, 1909; Braithwaite, 1949). It has been demonstrated that the causal mechanism in embryo is a haematoma arising from the anastomosis which precedes the formation of the stapedial arterial stem (Poswillo, 1973). The mandible begins to ossify from the 6-week-old embryo (Sperber, 1976); ossification is already fairly marked in the 10-week-old embryo (Kvinnsland, 1969). It is, therefore, in fact possible to diagnose this condition inutero. Careful examination of the intra-uterine X-ray of the present case indicated the total absence of the mandible, the hallmark of this particular condition. The presence of severe hydramnios would have alerted the obstetrician to the possibility of fetal abnormality. Confirmation of this abnormality by radiography at the end of the first trimester could have resulted in remedial action being taken then.
Figure 2. Frontal view of infant demonstrating very small mouth and markedly low-set ears.
small and premature; the pulmonary arteries were of medium size, and infiltrated by mainly eosinophils. Marked haemopoiesis was observed in the liver, and the kidneys demonstrated active nephrogenesis.
DISCUSSION In the sixth week of fetal life, the appearance of 6 prominences at the dorsal end of the first branchial groove marks the onset of development of the external auricles. These prominences fuse into two folds to form the developing pinna towards the end of the same week. The mandibular arch makes a contribution to the anterior fold, and the hyoid arch to the posterior fold. Further fusion of the two folds occurs at the upper end of the first branchial groove. In the present example, there was hardly any deformity in the pinnae, indicating that the development of the pinna is not entirely dependent on factors responsible for maturation of the ventral portions for the first and second arch derivatives. Maxillary development in this case was normal even though there was no mandible, supporting the
Figure 3. Lateral view demonstrating absence of mandibles.
APLASIA OF THE FIRST AND SECOND BRANCHIAL ARCHES
AC KN0W LE DG EME NTS Our thanks to Dr. K. C. Ng, Medical Superintendent of Kandang Kerbau Hospital, for permission to publish this case report, and the Radiology and Pathology Departments for their kind co-operation. Figures 2 and 3 were made possible by the courtesy of Dr. S. H. Kee. REFERENCES
277
Keen, J. A. (19551, A case of agnathia with a note on the development of the maxillary process, S. Air. J. Lab. Clln. Med.. 1: 197. Keith, A. (1909). Three demonstrations on congenital malformations of palate, face and neck, 6 r . Med. J.. 2: 483. Kvinnsland. S. (1969), Observations on the early ossification process of the mandible as seen in plastic embedded human embryos, Acta Odontol. Scand., 2 7 643. Poswillo. 0. (1973), The pathogenesis of first and second branchial arch syndrome, OralSurg.. 35: 302. Sperber. G. H. (1976). Craniofacial embryology, Bristol. J. Wrightand Sons Ltd., D110.
Altmann. F. (1957). The ear in severe malformations of the head, Arch. Otolaryngol , 66: 7. Braithwaite. F. and Watson. J. (1949). A report on three unusual cleft lips. Br. J. Plast. Surg.. 2: 38.
Correspondence to K. L. Tan, Department of Paediatrics, University of Singapore, Singapore.
Aplasia of the First and Second Branchial Arches
K. Y . WOON: and K . L. TAN2
Department of Paediatrics, University of Singapore, Singapore
Woon, K. Y. and Tan, K. L. (1979). Aust. Paediatr. J., 15, 275-277. Aplasia of the first and second branchial arches. A Case with the very rare syndrome of otocephaly is reported. It is possible to diagnose this condition in-utero by radiography. Since this is a lethal condition, remedial action can be taken in early pregnancy.
The very severe form of aplasia of the first and second branchial arches is represented in the syndrome of otocephaly which is invariably fatal.
CASE REPORT A 21-year-old female was admitted at 32 weeks' gestation for suspected intrauterine death. Her first pregnancy had been normal, resulting in the delivery of a healthy baby. On examination there was obvious hydramnios; the size of the abdomen was consistent with 36 weeks' gestation, and regular fetal heart sounds were audible. An abdominal X-ray of the mother was taken ar?d at that time interpreted as normal by the obstetrician (Fig. 1). She was admitted one month later in labour with leaking blood-stained liquor. The infant was delivered by forceps for fetal distress; the baby was abnormal and died one hour later. The appearance of the infant (birth weight 1375 gm, length 41 cm) is shown in Figure 2. There was an antimongoloid slant to the palpebral fissures with absent eye-lashes and eye-brows. The mouth was only a tiny central stoma with the mandibles conspicuously absent (Fig. 3). The most obvious features were the pinnae which were attached to the neck just below the head; their configuration was, however. fairly normal. The tongue was hypoplastic and the oral cavity very small. The penis was normal externally but the testes were impalpable. The limbs appeared to be normal. Autopsy demonstrated that the mandibles were absent; the thyroid, parathyroid and thymus were apparently normal. The testes were retro-peritoneal. Both the trachea and oesophagus appeared to be normal. Histology demonstrated a small focus of eosinophils in the epicardium near the apex of the heart. The lungs were 1 Senior Registrar Neonatal Unit 2 Associate Professor Department o f Paediatrics University of Singapore Head Neonatal Unit Kandang Kerbau Hospital
Received Janbary 25 1979
Figure 1. Abnormal X-ray of foetus which was interpreted as "normal". Note the absence of the mandibles.
276
AUSTRALIAN PAEDlATRlC JOURNAL
theory that the primordia for the maxillary processes are derived from mesenchyme which migrates from the ventral neural crest to form portions of the base of the skull and maxilla (Keen, 1955; Altman, 1957). The pathogenesis of this condition has been attributed to intrauterine facial necrosis due to failure of development of the stapedial artery (Keith, 1909; Braithwaite, 1949). It has been demonstrated that the causal mechanism in embryo is a haematoma arising from the anastomosis which precedes the formation of the stapedial arterial stem (Poswillo, 1973). The mandible begins to ossify from the 6-week-old embryo (Sperber, 1976); ossification is already fairly marked in the 10-week-old embryo (Kvinnsland, 1969). It is, therefore, in fact possible to diagnose this condition inutero. Careful examination of the intra-uterine X-ray of the present case indicated the total absence of the mandible, the hallmark of this particular condition. The presence of severe hydramnios would have alerted the obstetrician to the possibility of fetal abnormality. Confirmation of this abnormality by radiography at the end of the first trimester could have resulted in remedial action being taken then.
Figure 2. Frontal view of infant demonstrating very small mouth and markedly low-set ears.
small and premature; the pulmonary arteries were of medium size, and infiltrated by mainly eosinophils. Marked haemopoiesis was observed in the liver, and the kidneys demonstrated active nephrogenesis.
DISCUSSION In the sixth week of fetal life, the appearance of 6 prominences at the dorsal end of the first branchial groove marks the onset of development of the external auricles. These prominences fuse into two folds to form the developing pinna towards the end of the same week. The mandibular arch makes a contribution to the anterior fold, and the hyoid arch to the posterior fold. Further fusion of the two folds occurs at the upper end of the first branchial groove. In the present example, there was hardly any deformity in the pinnae, indicating that the development of the pinna is not entirely dependent on factors responsible for maturation of the ventral portions for the first and second arch derivatives. Maxillary development in this case was normal even though there was no mandible, supporting the
Figure 3. Lateral view demonstrating absence of mandibles.
APLASIA OF THE FIRST AND SECOND BRANCHIAL ARCHES
AC KN0W LE DG EME NTS Our thanks to Dr. K. C. Ng, Medical Superintendent of Kandang Kerbau Hospital, for permission to publish this case report, and the Radiology and Pathology Departments for their kind co-operation. Figures 2 and 3 were made possible by the courtesy of Dr. S. H. Kee. REFERENCES
277
Keen, J. A. (19551, A case of agnathia with a note on the development of the maxillary process, S. Air. J. Lab. Clln. Med.. 1: 197. Keith, A. (1909). Three demonstrations on congenital malformations of palate, face and neck, 6 r . Med. J.. 2: 483. Kvinnsland. S. (1969), Observations on the early ossification process of the mandible as seen in plastic embedded human embryos, Acta Odontol. Scand., 2 7 643. Poswillo. 0. (1973), The pathogenesis of first and second branchial arch syndrome, OralSurg.. 35: 302. Sperber. G. H. (1976). Craniofacial embryology, Bristol. J. Wrightand Sons Ltd., D110.
Altmann. F. (1957). The ear in severe malformations of the head, Arch. Otolaryngol , 66: 7. Braithwaite. F. and Watson. J. (1949). A report on three unusual cleft lips. Br. J. Plast. Surg.. 2: 38.
Correspondence to K. L. Tan, Department of Paediatrics, University of Singapore, Singapore.
