Harlequin ichthyosis - Prenatal diagnosis with two- and three-dimensional ultrasound at 30 weeks

Clinical History

A 25-year-old woman with no significant past history was referred for her first antenatal ultrasound at 30 weeks gestational age. Two- and three-dimensional ultrasonography was done. She delivered preterm by spontaneous normal vaginal delivery at 32 weeks. The neonate expired immediately after delivery.

Imaging Findings

Two- and three-dimensional sonography was performed. Fetal biometry corresponded with a gestational age of 30 weeks. Amniotic fluid was normal. The fetus showed abnormal facial features with a flat nose, a persistently open mouth in a fish-mouth-like configuration with protruding tongue, bilateral flattened rudimentary external ears, and hypoechoic mass lesions in front of each globe. Three-dimensional surface rendered images of the fetal face showed cracks in the skin. The fingers and toes were seen to be persistently in flexed position. No associated visceral anomaly was seen and rest of the ultrasound examination was normal.

Post-natal evaluation confirmed the ultrasound findings. Tiger stripes appearance of skin was noted with cracks in skin. Bilateral ectropion was noted presenting as swelling over each globe. Flat nose, flattened rudimentary ears, and open mouth in a fish-mouth-like configuration with protruding tongue was noted. Fingers and toes were flexed.

Discussion

Harlequin ichthyosis is a rare and lethal form of congenital ichthyosis. At birth, a newborn infant with harlequin ichthyosis has thickened, yellow-coloured, armour-like skin with fissures that divide the skin into polygonal sections. Facial anomalies include ectropion (eversion of the eyelids), eclabium (eversion of the lips), and a large, round, wide open mouth with the infant not being able to suck properly. The nose and ears are hypoplastic. The newborn appears to be encased in a tight, parchment-like membrane, which allows little movement and holds the limbs in a semiflexed position [1].

The first case of prenatal diagnosis of harlequin ichthyosis was reported in 1983 by Blanchet-Bardon et al [2]. The diagnosis was based on fetal skin biopsies under fetoscopy. However, the use of this traumatic method for prenatal diagnosis is limited to pregnant women with a previously affected child. The first case of prenatal sonographic diagnosis of harlequin ichthyosis was reported by Mihalko et al in 1989 [3].

Despite specialized treatment, death generally occurs within the first weeks of life due to skin infection. With close monitoring of skin and eyes, and treatment with vitamin A, survival has been prolonged [4].

Prenatal sonographic features of this condition have been described. The principal signs suggestive of harlequin fetus are absence of typical ear morphology, atypical facial dysmorphism, large open mouth, absence of typical nasal morphology, partitioned cystic formations in front of the eyes, thick skin, minimal fetal movement with stiff limbs in a semiflexed position, limb anomalies with hypoplastic fingers and toes and short phalanges, clubfoot, shriveled hands that do not open, hyperechogenic amniotic fluid, and an absence of associated visceral anomalies. The earliest sonographic diagnosis by three-dimensional ultrasound was at 22 weeks, in a second pregnancy after a first pregnancy with the same condition. In that case a scan was done at regular intervals of 15 days from early pregnancy [5]. In a seemingly normal pregnancy the earliest diagnosis was at 30 weeks [5, 6].

In conclusion, three-dimensional ultrasound can accurately diagnose congenital harlequin ichthyosis obviating the need to do fetal skin biopsy under fetoscopy. This is particularly important since it allows an antenatal diagnosis in patients with no past history of harlequin fetus.

Differential Diagnosis List

Final Diagnosis

Harlequin ichthyosis

URL:	https://eurorad.org/case/13759
DOI:	10.1594/EURORAD/CASE.13759
ISSN:	1563-4086