Prevalence, Morphology, Embryogenesis, and Diagnostic Utility of Umbilical Cord Vitelline Vascular Remnants.

The objective of this study is to better understand embryonic vitelline vascular remnants in the umbilical cord, to assess their prevalence, to categorize their morphology, and then finally to describe and assess inflammation arising from these structures. During routine placental sign out, the author noted the presence or absence of vitelline vessel remnants for 1 year; when present, he assessed their histologic patterns and noted whether there were neutrophils marginating from the remnants and into the adjacent Wharton's jelly and whether there was any other evidence of amniotic fluid infection in sections of placental disc, membranes, or cord. All cord sections with vitelline vessel remnants were immunostained for CD15 to document any infiltrates, to highlight patterns of infiltration, and to evaluate whether mild cases of umbilical phlebitis were associated with these lesions and were at risk of being missed. Vitelline vessel remnants were present in 4.2% of placentas examined. There were 5 vitelline vessel remnant histologic patterns identified providing insight into the vitelline vessel circulation. Funisitis, primarily neutrophilic, arising from vitelline vessel remnants was present in 70.3% of the 37 cords with vitelline vessel remnants. The presence of vitelline vessel remnant funisitis documents continued active circulation in these vascular structures, and vitelline vessel remnant funisitis was associated with the presence of other placental histological evidence of amniotic fluid infection in 53.8% of cases. The author also reviews normal embryology and the pathology of vitelline vessel remnants.