An odd looking terminal ileum

This patient was undergoing colonoscopy because of abdominal pain, weight loss and suspected thickening of the terminal ileum seen on CT
WHAT IS YOU ENDOSCOPIC DIAGNOSIS?
a) Crohn's disease
b) Adenocarcinoma
c) Lymphoma
d) Neuroendocrine tumour
​e) Tuberculosis

explanation

Endoscopically, there appear to be 'nodules' arising from below the overlying mucosa. When I first showed this case, almost everyone correctly identified this as a case of lymphoma.  Of course, MALT lymphoma in the stomach looks completely different with thickening and reddening of the gastric mucosa, usually with ulceration of the surface.

The reason why this looks entirely different to a gastric MALT lymphoma is because it is a completely different type of lymphoma!  Histologically, the submucosal nodules were made up of small to intermediate sized lymphoid cells clusters, forming solid sheets and balls. This is the classical endoscopic appearance of a Mantle Cell Lymphoma (MCL). 

MCL is a type of non-Hodgkin's lymphoma which arise within the 'mantle zone' that surrounds normal lymphoid follicles. It's presumably for this reason that endoscopically it looks like gross case of nodular lymphoid hyperplasia.   It's not a 'good lymphoma' as median life expectancy is only 6-7 yrs.   In this patient, a CT confirmed that there were large nodes both above and below the diaphragm. Although he had no symptoms our haematologists have started treatment with 'Ibrutinib' to reduce the risk of small bowel obstruction.

From today, you will all recognise the typical endoscopic appearances of a MCL !