[Hypoechogenic aspects of the ventral embryonic cephalic pancreas: a large prospective clinical study].

Global echogenicity of the normal pancreas increases essentially with lipomatous involution which is common with aging. However, the two embryologic different parts of the cephalic pancreas may present a different echogenicity: the "embryologic ventral" pancreas-posterior cephalic pancreas + uncinate process-is then hypoechoic because of less fatty involution. It is important to distinguish such normal variant from a pathological process. The clinical prevalence and morphologic characteristics of this normal variant have been prospectively studied in a large series of 446 patients including 275 females and 171 males. The study confirms the proportional increase of pancreatic echogenicity with age. The variant has a sharp female predominance: 27.5% of males vs 43.3% females, corresponding to a sex ratio of 1:1.52. Hypoechoic ventral embryologic cephalic pancreas is never encountered before the age of 25 and is most frequent in middle aged females with moderately echoic pancreas. There is not any difference in global cephalic pancreatic thickness between our positive group and a negative group of reference of 66 patients. These observations rather plead a genetic uneven fatty involution in positive cases instead of ventral pancreas atrophy in negative cases. The morphological and biometric characteristics of the hypoechoic embryologic ventral pancreas are rather stable. These are relatively independent from age, sex, and global pancreatic echogenicity.