*2.1.2. Hypotelorism*

**2.1. Anomalies of the orbits**

reoscopic vision to develop (**Figure 8**).

96 Congenital Anomalies - From the Embryo to the Neonate

the median line as gestation goes on [7].

**Definition:** Hypertelorism is an increased interocular distance.

**Embryology and pathogenesis:** At the first stage of the development of the human embryo, the eyes are to be found laterally, like in animals with panoramic vision. As the pregnancy evolves, the fetal eyes migrate toward the midline, thus generating the conditions for the ste-

There are at least two theories as to why hypertelorism may appear. The first theory states that there are several mechanisms causing it: the forward migration of the first half of the eyes, a midline tumor, meningoencephalocele for instance, causing the second half, or skull bones with abnormal growth vectors. The second theory links a splanchnocranium, which presents an abnormal growth, to the undeveloped bones which derive from the first branchial arches [8]. **Pathology:** Three parameters are used to measure the fetuses' ocular spacing: interpupillary distance, canthal distance, and interorbital distance. Hypertelorism is bilateral most of the times, with little incidents of unilateral cases associated with plagiocephaly and proboscis lateralis. Also, this condition is either isolated or accompanied by other malformations or clinical syndromes such as the median cleft syndrome and craniosynostoses. In craniosynostoses, hypertelorism syndromes such as Apert, Crouzon, and Carpenter are usually present [9].

**Figure 8.** The facial structures development, represented schematically between the 5th and the 10th week of gestation. During the early stages, we can notice the primitive eyes on both sides of the cephalic pole. However, they move toward

*2.1.1. Hypertelorism*

**Definition:** Hypotelorism is a decreased interorbital distance.

**Prevalence:** 1 in 20,000 births.

**Etiology**: Hypertelorism is almost always associated with other severe abnormalities, especially with the sequence of holoprosencephalic abnormality.

**Embryology and Pathogenesis:** Out of the mesenchymal mass there comes the craniofacial skeleton. This mass has two points of origin: the mesoderm and the neutral crest, the latter migrating to the region. The development of the median facial structures (forehead, nose, interorbital structures and upper lip) is closely linked to the forebrain differentiating process. It is possible that these two development steps are induced by the tissue, which lies between the prosencephalon and the stomodeum (the root of the primitive mouth), namely the prechordal mesenchyma. Thus, defects of the facial midline, for example, hypotelorism, are often linked to cerebral abnormalities, most often with holoprosencephaly. Hypotelorism can be found in association with trigonocephaly, microcephaly, Meckel syndrome and chromosome aberrations [10, 11].

**Ultrasound diagnosis:** It is based on the documentation of a reduced interocular distance. The interorbital diameter is lower than <5th and, together with the almost always present holoprosencephaly (**Figure 9**), is to be found among the midline migration defects; in this case, the hypotelorism can be extreme, as in cyclopia [10].

**Associated abnormalities:** In half of the cases, we encounter chromosomal defects, especially trisomy 13, as well as genetic syndromes [9].

**Investigations:** A thorough ultrasound examination should be conducted, including neurosonography, in order to find associated defects as well as invasive testing for karyotyping and array.

**Figure 9.** Axial scan a fetus at 14–15 weeks with alobar holoprosencephaly.

**Prognosis:** The prognosis and the management are decided on the accompanying malformations. Usually, the prognosis is poor, with high levels of mortality. In cases with normal karyotype, there is a high risk of mental retardation, depending on the degree of holoprosencephaly. **Associated abnormalities:** Chromosomal defects, especially trisomy 13, are found in more than 50% of the cases. The most common include: Goldenhar syndrome (1:3000 births), Fraser

Congenital Abnormalities of the Fetal Face http://dx.doi.org/10.5772/intechopen.73072 99

**Investigations:** Besides detailed ultrasound, karyotyping and array should be offered. Also, a fetal brain MRI may be useful to diagnose abnormalities (e.g., the absence of the optic nerve). **Prognosis and obstetrical management:** Isolated: good, with an altered life quality because of the esthetic aspect of the lesion: plastic surgery might be considered. Syndromic: prognosis

**Recurrence:** Isolated: no increased risk. Part of an autosomal recessive condition: 25%.

**Definition:** Dacryocystocele is a congenital obstruction of the nasolacrimal duct, resulting in

**Ultrasound diagnosis:** Cyst (75% unilateral and 25% bilateral) between the lower part of the orbit and the nose. About 90% of the cases are due to delayed canalization of the lacrimal duct

**The differential diagnosis:** includes an anterior cephalocele, hemangiomas, and dermoid cyst. Usually, hemangiomas have a solid appearance or multiple septae, and they are shown as exophytic lesions with an echogenicity, similar to the placenta. Among the complications of hemangiomas, we should include ulceration, bleeding, infection, and scar formation. The dermoid cysts have often a superolateral location. It is difficult to differentiate anterior cephaloceles from these lesions. If hydrocephaly is present, we should suspect

syndrome, Fryns syndrome and Meckel-Gruber [9].

*2.1.4. Dacryocystocele*

**Prevalence:** 1 in 4000.

a cephalocele [12, 13].

beyond 32 weeks gestation.

is very poor. Management depends on the specific syndrome [11].

**Figure 10.** This picture shows a case of anophthalmia, prenatal and postnatal aspects.

cystic dilatation of the proximal part of the duct. (**Figure 11**).

**Recurrence:** Isolated: no increased risk. One percentage risk of trisomy and 13.25% risk of being part of an autosomal recessive condition [11].
