Is omentectomy necessary in the treatment of benign or malignant abdominal pathologies? A systematic review

Normal saline remodels the omentum and stimulates its receptivity for transcoelomic metastasis

The omentum contains immune cell structures called milky spots that are niches for transcoelomic metastasis. It is difficult to remove the omentum completely, and there are no effective strategies to minimize the risk of colonization of preserved omental tissues by cancer cells that circulate in the peritoneal fluid. Normal saline is commonly administered into the peritoneal cavity for diagnostic and intraoperative lavage. Here we show that normal saline, when administered into the peritoneal cavity of mice, is prominently absorbed by the omentum, exfoliates its mesothelium, and induces expression of CX3CL1, the ligand for CX3CR1, within and surrounding the omental vasculature. Studies using CX3CR1-competent and CX3CR1-deficient mice showed that the predominant response in the omentum following saline administration is an accumulation of CX3CR1+ monocytes/macrophages that expand milky spots and promote neoangiogenesis within these niches. Moreover, saline administration promoted the implantation of cancer cells of ovarian and colorectal origin onto the omentum. By contrast, these deleterious effects were not observed following i.p. administration of lactated Ringer's solution. Our findings suggest that normal saline stimulates the receptivity of the omentum for cancer cells and that the risk of colonization can be minimized by using a biocompatible crystalloid for lavage procedures.

CT and MR imaging of the greater omentum: Pictorial essay

The greater omentum is a unique anatomical structure that serves a critical function in the containment of inflammatory and infectious processes within the abdominal cavity. It is also a common site of involvement by metastases, as well as the primary location for various pathologic lesions of clinical significance. Its fibroadipose composition, large size, and position in the most anterior aspect of abdomen allow accurate visualization of the greater omentum on CT and MR images. Careful evaluation of the greater omentum can provide important clues to the diagnosis of the underlying abdominal disorder. The aim of this article is to present the normal appearance of the greater omentum, and the wide spectrum of its pathological features as demonstrated on CT and MRI of the abdomen.