Mesenteric LMs represent rare congenital anomalies which may embody chylous or non-chylous content. The pathological mechanisms explaining this phenomenon are poorly understood and not yet described. Furthermore, the current management approach does not take into consideration the mesenteric LMs content. Our study defines a relationship between the lymphatic mesenteric cysts' content and the histological evidence of lymphatic malformations (LMs) within the bowel wall.

We retrospectively investigated all cases with mesenteric LMs treated surgically at our Department from 1999 to 2018.

11 patients (n=6 female, n=5 male) were included in our analysis. Seven cases presented with LMs located in the jejunal mesentery, 3 cases in the ileo-coecal region, and only 1 LMs case in the mesocolon transversum and omentum. Seven children showed non-chylous content LMs, and 4 presented with chylous content LMs. Intestinal resection was performed in all 4 patients with chylous content LMs and 4 patients with non-chylous LMs. Histopathologic evaluation of the surgical specimens determined that only LMs with chylous content displayed malformed lymphatic channels throughout the bowel wall. The resected small bowel of 4 patients with non-chylous content showed no LM extension throughout the intestinal wall.

LMs with chylous content seem to develop from malformed lymphatic channels within the bowel wall; in this case segmental intestinal resection is mandatory. In contrast, mesenteric LMs with non-chylous content may potentially be treated without bowel resection if blood supply can be preserved. This finding is, to the best of our knowledge, presented here for the first time.