Diffuse lymphoplasmacytic infiltration of the small intestine with damage to nerve plexus. A cause of intestinal pseudo-obstruction.

We describe the clinicopathologic characteristics of three patients with chronic intestinal pseudo-obstruction and malabsorption. The patients were young women (average age, 25 years) who presented with abdominal pain, nausea, vomiting, diarrhea, and weight loss that led to extreme inanition and death in two patients despite multiple treatment schemes. The evolution of the process averaged 8 years. No case manifested evidence of malignant lymphoproliferative progression. Histologically, a diffuse lymphoplasmacytic infiltrate that affected all the layers of the intestinal wall was observed in full-thickness biopsy specimens. The proliferating lymphocytes were small and mixed with mature plasma cells that proved to be polyclonal on immunohistochemical analysis. An outstanding finding in all three cases was extensive damage to submucosal and myenteric nerve plexus associated with a lymphoid infiltrate. Quantification of the myenteric plexus by using immunohistochemical and morphometric techniques also revealed a marked reduction in their number. We concluded that diffuse lymphoplasmacytic infiltration of the small intestine associated with damage to the intestinal nerve plexus constitutes a specific disorder that is different from other diseases that produce intestinal pseudo-obstruction.