Teratomas are neoplasms comprised of elements from all three germ layers and occur rarely in the craniofacial and neck regions. Pathology is usually of a benign nature. They are reported in many different sites including nasal tip,nasopharynx and cervical. They may also occur intracranially. These tumours are generally large, extending anterolaterally, and often leading to hyperextension of the fetal neck. Rapid growth of the tumour may occur, with distortion and deformity of facial bones. Prognosis is poor with a high rate of intrauterine death (50%) and early neonatal death due to difficult airway management, respiratory compromise and surgical inoperability. Early resection of smaller lesions following effective resuscitation can be life-saving.
Standard coronal and sagittal views of the face and neck may reveal a large complex tumour with solid and cystic components. The origin of this mass is frequently the anterolateral portion of the fetal neck. This space occupying lesion may predispose to oesophageal compression and mechanical obstruction of fetal swallowing with hydramnios (30%). If the mass is sufficiently large, hyperextension of the neck may be an associated feature. Involvement of the facial region may render anatomical localisation of site of origin challenging. Calcification in the tumour is a distinguishing feature of teratomas, and is present in 40 to 50%, but this feature has not been reported prenatally to date. An intracranial teratoma may present with macrocephaly.
A goitre will present as a mainly solid mass, with echolucent areas. Cysts of the branchial cleft and thyroglossal duct are embryologic remnants occurring in characteristic locations. The former is found anterolateral to the carotid sheath, and the latter is located in the midline. Both tend to be unilocular. Solid masses of the neck include neuroblastoma, lipoma, salivary gland tumour, mesenchyme sarcoma and neurofibroma. Lymphangiomas are often multiloculated, with linear septations of variable thickness. Solid portions are found within and between the cysts. Encephalocele can be confused with haemangioma, particularly when the position is midline and occipital. A careful search should be made for an underlying bony defect, and the absence of pulsations. A haemangioma is a cystic, solid or mixed mass. Occasionally it will be accompanied by multiple internal homogeneous echogenic reflections, representing calcified areas. These are small and widely scattered, unlike the gross calcification of a teratoma. Cystic areas may be pulsatile. Doppler velocimetry should demonstrate low-resistance blood flow through the cystic areas.
Teratoma has a complex echo pattern, with solid and cystic components
Calcification may be present in both haemangioma and teratoma, however gross calcification is generally restricted to teratoma, and fine scattered calcification to haemangioma
When present in the neck there may be associated hyperextension, oesophageal compression and mechanical obstruction to fetal swallowing with hydramnios (30%)
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