Thomas E Hynd1, Cadie L Buckley, Scott Lozanoff. 1. Department of Anatomy, Biochemistry and Physiology, John A. Burns School of Medicine, University of Hawaii, Honolulu, HI 96813, USA. hynd@hawaii.edu
Abstract
BACKGROUND: Cephalothoracopagus twinning is extremely rare, and it is characterized by fusion of the head and thorax, two separate spines, pelves, and fore- and hindlimbs. CASE: In this case study, we describe cephalothoracopagus twinning in an embryonic mouse displaying a large but exencephalic head, median facial cleft, a single eye, and a second hindbrain rotated roughly 90° from a second spinal cord. There is a bony connection joining the clavicles, resulting in merged asternal thoracic cavities containing two hearts and four lungs. The abdominal cavities contain double caudal digestive tract structures, but a single esophagus and stomach. CONCLUSION: There are several proposed theories regarding the mechanism of spontaneous conjoined twinning; however, the specific mechanisms are still largely unknown. In this report, we highlight the morphological features in a murine example of cephalothoracopagus twinning, furthering our understanding of this rare occurrence while also demonstrating developmental morphogenesis consistent with that reported for human conjoined twins.
BACKGROUND: Cephalothoracopagus twinning is extremely rare, and it is characterized by fusion of the head and thorax, two separate spines, pelves, and fore- and hindlimbs. CASE: In this case study, we describe cephalothoracopagus twinning in an embryonic mouse displaying a large but exencephalic head, median facial cleft, a single eye, and a second hindbrain rotated roughly 90° from a second spinal cord. There is a bony connection joining the clavicles, resulting in merged asternal thoracic cavities containing two hearts and four lungs. The abdominal cavities contain double caudal digestive tract structures, but a single esophagus and stomach. CONCLUSION: There are several proposed theories regarding the mechanism of spontaneous conjoined twinning; however, the specific mechanisms are still largely unknown. In this report, we highlight the morphological features in a murine example of cephalothoracopagus twinning, furthering our understanding of this rare occurrence while also demonstrating developmental morphogenesis consistent with that reported for human conjoined twins.