small bowel mesentery

hello again and welcome to anotherepisode of cases in radiology. i'm frank gaillard the editor of radiopaedia.organd today we're going to be looking at at a ct of the abdomen in aseventy-year-old female who presented with epigastric pain. her only relevant medical history was that of apast cholecystectomy. as always now is a perfect time to pausethis video and take a minute or two to have a look at the case at your own pace. just follow the link which is eithervisible on your screen or included in the video description.

so here we have coronal and axial stacks through the abdomen. two main findings should have been evident. the first isthat there is a small bowel obstruction as envisaged by these enlarged loops of dilated bowel. these can be traced down into the lowerabdomen to this point where there is an abrupttransition from the distended

proximal lumen to the collapsed more distal lumen which has intussuscepted into the distal loop of bowel. this is also seen on axial imaging at this point where there is almost thecharacteristic donut appearance with mesenteric fat having been pulled into the lumen of the bowel.

going back to the coronal imaging there is the impression off a lead pointmass. the other notable findings are bilateralvery large renal masses, larger on the right. these appear centrally necrotic or cystic. there are numerous lymph nodes scatteredthroughout the mesentery which appear enlarged. but no other solid masses are identified. incidental findings include a largesimple renal cyst on the right.

the first question you should ask yourself is whether or not the bilateraladrenal masses and the small bowel intussusception are related. let's first talk about intussusception. intussusception is when one part of the bowel gets sucked into the more distal bowel and is further advanced by the action of peristalsis. in children this is most oftenidiopathic without an underlying cause identified, or certainly not anunderlying pathological cause; its most often attributed to prominent lymphoid tissue in the submucosa.

in adults however a lead point isusually identified and in most instances it is that of a malignancy. in the large bowel it is that of a colorectal carcinoma which isby far the most common, however small bowel lymphoma and metastases to both large or small bowel particularly from malignant melanoma,breast cancer or lung cancer are identified.

a number of benign neoplasms are alsoencountered. as are some congenital abnormalities although these would beunlikely to first present in a seventy-year-old. inflammatory and trauma has alsobeen reported but is unlikely. let's turn our attention to the adrenalglands. by far the most common cause ofbilateral adrenal masses is that of metastases;

and the primary tumors to considerare those of lung cancer, breast cancer renal cancer which is not evident inthis case, gastrointestinal malignancies, malignant melanoma and lymphoma. it is also worth considering primary tumours although most often these are unilateral. pheochromocytomas for example areencountered bilaterally in up to ten percent ofpatients - whether this represents

metastatic disease to the contralateraladrenal gland or synchronous tumours is debatable. going back to this case we are left withfour options. the first is that the small bowel mass and the bilateral adrenal masses are unrelated and that the adrenal masses were merelyincidentally found due to the presentation of a small bowel obstruction. the second is that they are related and that both represent

metastatic disease. as we saw the primary lesions to beconsidered are breast cancer, lung cancer, and melanoma. the third and fourth possibilities are that one of these lesions represent the primary and that the otherrepresent metastase. for example, the small bowel mass may be a primary adenocarcinoma or carcinoid of the small bowel with adrenal metastases.

or potentially that we have bilateraladrenal malignancies with metastases to the small bowel. review of a chestx-ray and inspection of the breasts remonstrated no obvious lung mass or breast mass. further questioning of the patient didhowever reveal that seven years ago she had had a malignant melanoma excised from herback. the patient went on to have a laparotomy

and had the small bowelintussusception resected and the adrenal glands biopsied. malignant melanoma was the diagnosis inboth instances. so this case is a good example of how systematically working through thedifferential diagnosis for separate lesions enables theunderlying cause to be narrowed down. malignant melanoma is particularly commonin australia because all a population ofimmigrants who have fair skin from northern european countries

now exposed to the harsh sun and the depletedozone layer. it is a sinister tumour insofar that alesion thought to completely have been excised many many years ago can present with metastatic disease and often cando so in unusual ways. it is one of the classic tumours to metastasise to small bowel and should be thought of high on thelist when such presentations are encountered. hope to see you again next time. take care.