Presentation
Intermittent right iliac fossa pain for the past year.
Patient Data
Marked circumferential bowel wall thickening involving the terminal ileum as well as the caecum. The thickened terminal ileum shows aneurysmal dilatation, whereas the proximal distal ileal bowel loops are not dilated but collapsed.
Fat stranding adjacent to the thickened bowel loops with thickened peritoneum.
Multiple enlarged lymph nodes at the right iliac fossa, paracaval, aortocaval and para-aortic region, some having low attenuating component possibly representing necrosis.
Appendix is normal in calibre.
No intramural gas, pneumoperitoneum or portal venous gas.
No focal liver lesion. Simple left renal cyst. No ascites.
Annotated images show the aneurysmal dilatation of terminal ileum and multiple enlarged abdominal lymph nodes.
The proximal distal ileum is not dilated, whereas primary small bowel carcinoma (such as adenocarcinoma) would usually cause proximal bowel loop obstruction.
Case Discussion
CT features are in keeping with terminal ileitis, where there are a myriad of differential diagnoses. However, with the presence of adjacent necrotic abdominal lymphadenopathy and characteristic aneurysmal dilatation of the terminal ileum without proximal ileal dilatation, this is likely to represent small bowel lymphoma. Another differential diagnosis to consider in this part of the world where tuberculosis is endemic, is infectious ileitis by Mycobacterium tuberculosis.
The patient proceeded to right hemicolectomy.
Histopathology of the surgical sample:
Microscopic description
The ileal tumour is composed of atypical lymphoid cells infiltrating through the bowel wall into peri-ileal fat. The cells are medium to large sized with mildly pleomorphic round to oval nuclei showing coarse chromatin pattern and 1-2 nucleoli. Mitoses are seen. The resected lymph nodes are invaded by tumour cells. Most of the nodes show loss of normal nodal architecture and an infiltrate of similar cells are seen in most with some matter nodes. A few of the nodes are necrotic. The bowel resection margins are free of malignancy.
The appendix shows intact mucosa and muscle layers with congested serosa infiltrated by scattered polymorphs.
Immunohistochemistry:
The cells are positive for CD20, MUM-1, BCL-2 and >60% of cells show Ki-67 activity. The cells are negative for CD3, Cd10, Cd5, cyclin D1 and Tdt.
Right hemicolectomy for ileal tumour- ileal diffuse large B-cell lymphoma, activated B-cell phenotype. The excision margins are free of malignancy.
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