PMC4508281_01
Preoperative images. a Ultrasonography showed the "target sign" in the lower abdomen. b Enhanced CT revealed ileocolic intussusception and stretched mesenteric vessels. c The outer wall of the area of intussusception consisted of an edematous ileum (inner layer; black arrow) and dilated colon (outer layer; white arrow). d An enema examination showed "crab's claw sign" in the transverse colon.
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Fig1
An ultrasonography examination of the abdomen showed a target sign at the lower abdomen, indicating the existence of intussusception (Figure 1). Enhanced computed tomography (CT) also revealed ileocolic intussusception with a suspicious looking mass (Figure 1). An attempt at hydrostatic reduction with gastrografin  (Bayer Yakuhin, Osaka, Japan) was not successful (Figure 1); therefore, an emergent operation was conducted.
Abdominal CT at previous clinic. This CT was performed 5 weeks before he admitted to our hospital. Retrospectively, intussusception could be pointed out (arrow).
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Fig2
In addition, an examination of abdominal CT performed at the previous clinic 5 weeks earlier made us suspicious of signs of ileocolic intussusception (Figure 2).
Intraoperative findings. a Ileocolic intussusception was confirmed. Laparoscopic reduction failed. b The mesentery was markedly thickened, and the ileum was edematous. Although the tumor (arrow) in the terminal ileum was partially reduced, manual reduction was unsuccessful. Ileocecal resection was performed.
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Fig3
Initially, we performed probe laparoscopy, which revealed ileocolic intussusception, serous ascites and a markedly edematous ileum and mesentery (Figure 3).
Resected specimen. a The tumor (black arrow) was located on the antimesenteric side 2 cm oral to the ileocecal valve. The mucosa of the ileum was markedly edematous and erosive (arrowhead). b The tumor was hard and contained a white section. The shape of the tumor was distorted, especially in the ileal serosa.
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Fig4
In the resected specimen, a 3 cm submucosal firm mass was found 2 cm oral from the ileocecal valve (Figure 4). In contrast, immunostaining for CD3 (data not shown), TdT (Figure 4d), CD34, CD23 and cyclin D1 was negative (data not shown).
Representative histological images of the tumor cells in the resected specimen. a Hematoxylin-eosin (HE) stain. b-d Immunohistochemistry. b CD20. c BCL2. d TdT. Positive cells stained brown on immunohistochemistry. Original magnification x400. Bar 50 mum.
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Fig5
Histologically, the ileocecal mass was composed of the transmural diffuse proliferation of medium- to large-sized lymphoid cells (Figure 5a). Immunohistochemistry revealed that the tumor cells were positive for CD20 (Figure 5b), CD79a (data not shown) and Bcl-2 (Figure 5c).