Introduction

Aneurysmal dilatation of the small bowel is a radiological pattern seen when malignant cells invade the muscularis propria and disrupt the autonomic nerve plexus causing bowel lumen enlargement and associated wall thickening¹. It was first described in 1969 by Cupps who noted the pattern in 35% of small bowel lymphoma cases on fluoroscopic barium studies².

Case report

A 23-year-old male without the previous conditions seek medical attention for a growing mass in the left axilla. Associated symptoms of weight loss, diaphoresis, and mild abdominal pain were also noted. After a biopsy of the mass was performed, a diagnosis of high-grade B cell lymphoma was made. Initial extension abdominal computed tomography (CT) with intravenous contrast showed nonspecific bowel wall thickening. Subsequent anterograde enteroscopy revealed severe inflammation of the jejunal mucosa with ulceration and cobbled appearance. Progressive, severe abdominal pain and intractable emesis prompt for a new CT. The most relevant findings were bowel wall thickening involving jejunum and ileum, abnormal dilatation up to (aneurismal dilatation), ileo-ileal jejunal invagination, and multiple lymphadenopathies (Fig. 1).

Figure 1 A 23-year-old male with aneurysmal dilatation of the small bowel. Computed tomography of the abdomen (A) coronal soft-tissue window and (B) axial before chemotherapy. 

In face of worsening symptoms and CT findings, exploratory laparotomy was carried out. Due to an increased risk of extensive intestinal resection, enterotomies and other possible complications, additional interventions were withheld, and the surgical procedure was interrupted. Symptoms resolved after conservative treatment and adjuvant chemotherapy. A follow-up CT 2 and 5 months after chemotherapy showed significant improvement in bowel dilation and thickening (Fig. 2).

Figure 2 A 23-year-old male with aneurysmal dilatation of the small bowel. Computed tomography of the abdomen (A and B) coronal and axial soft tissue window 2 months after chemotherapy. (C and D) Coronal and axial soft tissue window 5 months after chemotherapy. 

Discussion

Small bowel tumors only represent 5% of all neoplasms in the GI tract. Primary GI lymphoma is far less common than secondary GI involvement³. In 5-20 % of all extra nodal non-Hodgkin’s lymphoma there is compromise of the GI tract, mostly non-Hodgkin’s lymphomas³,⁴.

It has been classically stated that the most frequent site of GI lymphoma is the stomach, followed by the small intestine, colon, cecum, and esophagus. In the small bowel, the distal ileum is most frequently affected, in line with its highest concentration of lymphoid tissue. The most common histologic lymphoma subtype is diffuse large B cell lymphoma⁵,⁶.

Four major patterns of small bowel lymphoma have been identified on radiographic studies. First, lymphoma can appear as multiple nodules within the small bowel⁶. Second, lymphoma can appear as a single mass lesion. Third, lymphoma can be infiltrating and appear as wall thickening with destruction of the normal small bowel folds and aneurysmal dilatation of the affected bowel loops. This has been described in up to 50% of cases. The fourth pattern is that of an exophytic mass. Other findings such as lymphadenopathy and hepatosplenomegaly are common⁶-⁸.

In our case, nodal non-Hodgkin’s lymphoma compromised multiple segments of small intestine with aneurysmal dilatation, multiple lymphadenopathies, and secondary invagination. Classically described by Norfray, aneurysmal dilatation occurs as the lymphoma grows and infiltrates along the bowel axis. Various mechanisms induce bowel dilation and thickening: infiltration by tumor cells weakens the bowel wall in the absence of desmoplastic reaction and fibrosis. The small intestinal wall weakening occurs in several ways: the infiltrating tumor cells stretch the muscle fibers; once stretched beyond double their normal length, contracting ability is lost; the infiltrating tumor cells invade and obstruct the lymphatic and vascular channels, resulting in anoxia of the muscle fibers which become necrotic; and the necrotic epithelial lining is sloughed off as bowel content passes through the lumen⁹,¹⁰. The loss of necrotic tissue surrounding the lumen eventually creates a cavity. In the end, the aneurysmal dilatation is caused by this enlarged lumen and weakened muscles which cannot contract against the intra luminal pressure⁷.

Originally thought to be pathognomonic for lymphoma, subsequent reports had described similar findings with GI stromal tumor, leiomyosarcoma, amyloidosis, primary adenocarcinoma, and metastasis¹¹,¹².

Most reported cases have been diagnosed after surgical resection of the affected segments of small bowel. In our patient, endoscopic and percutaneous studies permitted histologic confirmation of lymphoma involvement.

Surgical management of invagination and extensive aneurysmal dilation was risky; thus, conservative treatment and chemotherapy were favored over surgery.

Conclusion

Aneurismal dilation of the small bowel is an infrequent radiologic pattern mostly associated with intestinal lymphoma. We described a case of young men with representative features in which medical management improved symptoms. Follow-up studies revealed persistent dilation despite bowel thickening.