Otocephaly: Prenatal and postnatal imaging findings.

Dear sir,

Otocephaly is a rare anomaly of the ventral portion of the first branchial arch. Prenatal diagnosis is usually very difficult with the majority of the cases being diagnosed incidentally. The cases have been usually diagnosed in the third trimester. We present a case which was diagnosed incidentally in the second trimester in a non-consanguinously married asymptomatic primigravida.

A 22-year-old, asymptomatic primigravida, with no medical and family history of any congenital anomalies or consanguinity, presented for routine antenatal examination at 24 weeks of pregnancy. There was no antenatal history of infection/radiation or toxin exposure/drug intake. She was advised ultrasonography (USG) to rule out any anomalies. She had a previous scan in the first trimester which had been reported as normal.

Ultrasound examination was difficult because of polyhydramnios. On examination, there was a single live fetus with fetal maturity of 24 weeks. Detailed examination showed multiple anomalies of face which revealed a prominent proboscis and hypotelorism. Also, the mandible was not visualized and the malar area appeared to be hypoplastic. Ears could not be made out; however, there appeared to be an extra layer of soft tissue in the region of neck [Figure 1a and b]. No intracranial or other congenital abnormality was detected. Umbilical cord revealed three vessels. Placenta was normal and was located in the region of fundus of the uterus. A diagnosis of otocephaly was made.

Figure 1

(a) Sagittal ultrasound scan performed in the antenatal period reveals single fetus with agnathia, low-set ears, hypoplasia of malar areas and presence of proboscis. There is also polyhydramnios. (b) Transverse ultrasound scan reveals hypotelorism, proboscis and polyhydramnios

Magnetic resonance imaging (MRI) was performed on 1.5 T scanner, using fat-suppressed single-shot echo sequence to further evaluate the anomalies and confirm the diagnosis. Findings similar to those seen on USG were observed on MRI [Figure 2]. The fetus was terminated. The external appearance was consistent with the diagnosis of otocephaly [Figure 3]. A computed tomogram (CT)] and radiograph [Figures 4 and 5] performed at this stage revealed absent mandible and presence of proboscis.

Figure 2

Sagittal MRI scan of the intrauterine fetus reveals agnathia, hypoplasia of the malar area, presence of proboscis and polyhydramnios. Intracranial structures appear normal

Figure 3

Terminated fetus with features of otocephaly

Figure 4

(a) Sagittal reconstruction of axial CT scan images of the terminated fetus reveals agnathia, hypoplasia of the malar area, synotia, microstomia and proboscis. (b) Axial CT scan at the level of mid face with a blind ending orifice

Figure 5

Radiograph face antero-posterior and lateral view reveals agnathia, hypoplasia of the malar area, hypotelorism and proboscis

Otocephaly is a rare and lethal malformation complex involving the first arch and consists of microstomia, aglossia, agnathia and synotia. The defect is in the ventral portion of the arch.[1] It was first described by Kerckring in 1717. Its estimated prevalence is less than 1 in 70,000 births.[23] In addition to involving the first branchial arch structures, it may also result in dysmorphogenesis of other midline craniofascial field structures, such as the forebrain, and axial body structures. Roughly half the cases reviewed by Faye-Petersen et al. exhibited hypotelorism or cyclopia with or without probosciform nose and holoprosencephaly. Other associations described are lingual and/or palatal clefting, variety of axial abnormalities affecting skeletal, genitourinary, gastrointestinal, and/or cardiovascular systems, pituitary absence/hypoplasia, adrenal aplasia/hypoplasia, thyroid hypoplasia and pituitary axis insufficiency.[2] Prenatal diagnosis of otocephaly is usually very difficult. The majority of cases were usually found incidentally after other anomalies such as holoprosencephaly, encephalocele, situs inversus totalis or renal defects were identified.[1] Most of the cases are diagnosed during the third trimester. Polyhydramnios is frequent in association with otocephaly. Differential diagnosis includes Treacher Collins syndrome, Goldenhar syndrome and Mobius syndrome.[4]