ABSTRACT
The first report on a mesenteric cyst was published by an
Italian anatomist in 1507.1 Since then, the origin and
classification of mesenteric and omental cysts has been a
matter of debate. Moynihan attempted in 1897 a differentia-
tion of abdominal cysts on the basis of fluid content.2 Serous
cysts are characterized by a translucent, straw-colored fluid of
low specific gravity. Their chemical composition is similar to
plasma. In contrast, chylous cysts contain an opaque fluid of
high specific gravity, with lipids and fat globules contributing
to the fluid content. Subsequent attempts at a more
appropriate classification of intra-abdominal cysts have
been based on suspected etiology initially proposed by Beahrs
et al. in 1950.3 However, the etiology of many intra-
abdominal cysts is questionable, rendering classifications of
this type of limited clinical usefulness. A more appropriate
classification, based on histologic findings, was proposed in
1987 by Ros et al.4 This differentiation is applicable to all
operative cases and can provide the basis for a more uniform
evaluation of the clinical and pathologic characteristics of
these cysts (Box 57.1).
