Diprosopus: A Rare Case of Craniofacial Duplication and a Systematic Review of the Literature

Abstract

In 1990, Gorlin et al. described four types of craniofacial duplications: (1) single mouth with duplication of the maxillary arch; (2) supernumerary mouth laterally placed with rudimentary segments; (3) single mouth with replication of the mandibular segments; and (4) true facial duplication, namely diprosopus. We describe a newborn born with wide-spaced eyes, a very broad nose, and two separate mouths. Workup revealed the absence of the corpus callosum and the presence of a brain midline lipoma, wide sutures, and a Chiari I malformation with cerebellar herniation. We conducted a systematic review of the literature and compared all the cases described as diprosopus. In 96% of these, the central nervous system is affected, with anencephaly being the most commonly associated abnormality. Other associated anomalies include cardiac malformations (86%), cleft palate (63%), diaphragmatic hernia (13%), and disorder of sex development (DSD) (13%). Although the facial features are those that first strike the eye, the almost obligate presence of cerebral malformations suggests a disruptive event in the cephalic pole of the forming embryo. No major monogenic contribution has been recognized today for this type of malformation.

Keywords: case report; craniofacial duplication; diprosopia; diprosopus.

Figure 1

Data extraction method: In the PRISMA 2020 flow diagram for new systematic reviews, which included searches of databases and registers, the flow of information through the different phases of the systematic review is shown. It maps out the number of records identified, included, and excluded and the reasons for exclusions.

Figure 2

Photographs of the face of the proband showing the peculiar phenotype.

Figure 3

Brain ultrasound: enlargement of the third ventricle and agenesis of the corpus callosum.

Figure 4

X-ray of the skull: On both the AP image and the lateral projections, it is difficult to recognize the duplication of the maxilla and mandible. The coronal and sagittal sutures are wide.

Figure 5

Cranial CT (3D volume rendering reconstruction): duplication of the mandible and, partially, of the maxilla, with partial duplication of the oral cavity and two distinct mouths. Note also the wide cranial sutures.

Figure 6

Brain contrast CT (sagittal MPR): agenesis of the corpus callosum (a) with a small anterior midline lipoma (b); black allow and small posterior fossa with cerebellar tonsillar ectopia, the tonsils extending below the level of the foramen magnum (a).