Carcinoid tumor - terminal ileum

Case contributed by Dr Michael P Hartung

Presentation

Right flank pain, nausea, chills.

Patient Data

Age: 50 years
Gender: Female
CT

Presentation

There is a subtle, spiculated soft tissue density with a fleck of calcification adjacent to the right terminal ileum. This is very easy to overlook on axial imaging, but more apparent on a few of the coronal reformatted images.

CT

Work-up

Soft tissue thickening of the terminal ileum with adjacent spiculated soft tissue density projecting into the mesentery. There is a fleck of calcification along the posterior margin. The relationship of the terminal ileum can be best appreciated on coronal reformatted images.

Annotated

Arrows indicate the site of desmoplastic reaction along the right terminal ileum on both the noncontrast and contrast enhanced studies.

Preoperative diagnosis: Carcinoid tumor in the small bowel, terminal ileum.
Operation Laparoscopic-assisted right hemicolectomy with primary anastomosis.

Specimen:
Terminal ileum and right colon. 
Further resection proximal margin of terminal ileum. 
Further resection distal margin of proximal transverse colon.

Findings: The patient had a mass which had a terminal ileum just next to the cecum which was puckered in on the side with no other dense adhesions. This was freed up and our resection made proximally in the small bowel and distally in the transverse colon. This was done laparoscopically and then primary anastomosis was done via a mini laparotomy around the umbilicus.

Her preop labs showed serotonin level elevated at 699. Otherwise a 5-HIAA test was 6.5, which was within the normal range of 2 to 8. In addition patient had a normal chromogranin A level of 50, with the normal reference value being less than 90.

Procedure

...We inserted a 10 mm laparoscope and surveyed the abdomen. There were no obvious liver lesions. There was no specific inflammatory response except for in the right lower quadrant at the terminal ileum where the mass was visualized and had a puckered appearance, drawing mesentery in around it at the end of the terminal ileum/ileocecal valve area.

...This allowed us visualization in the terminal ileum and cecum. The appendix was also seen. This was gently dissected free, taking down the peritoneal lining and lateral peritoneal reflection and being able to free up the terminal ileum, as well as the pelvic side wall and along the white line of Toldt. We took down the omentum at the level of the transverse colon, taking down any adhesions between the colon and freed the colon and its mesentery from the surrounding tissues. We came across the end of the terminal ileum about 10 to 12 cm proximal to where the mass was seen in the terminal ileum using an EndoGIA blue staple load.

We dissected further near the proximal transverse colon, visualizing within the mesentery where we could make a hole in order to accommodate the Endo GI blue staple load. We fired across the colon laparoscopically using a 60 cm EndoGIA blue staple load. We came across the mesentery between these areas laparoscopically using a harmonic scalpel, dividing the mesentery between the small bowel and large bowel mesentery. Once the specimen was freed up completely we decided to do a mini laparotomy in the midline around the umbilicus in order to accomplish primary anastomosis in a safe manner. We made an incision connecting the 2 port sites, dissected down through skin and subcutaneous tissues using Bovie electrocautery to reach the level of the fascia which was incised and continuing the incision through the previous port site up around the umbilicus to the right side for about 4 to 5 cm above the umbilicus. We reached the level of peritoneum and incised through this, given the patient had just been on CO2 for the laparoscopic portion.

We visualized the cut ends of the bowel and removed the specimen. We passed the specimen off to pathology. There was a hard, firm mass encroaching on the ileocecal valve area. No other abnormal areas were seen or palpated. The specimen was not opened and we sent it to pathology whole....

Gross description:
Received without fixative identified as cecum is a 13 cm segement of cecum/ascending colon with an attached 10 cm segment of terminal ileum and an attached 4 x 0.6 cm unremarkable appearing appendix. The distal terminal ileum features a tan-yellow well circumscribed mass measuring 1.9 x 1.5 x 0.7 cm. The serosa is slightly umbilicated over this area. The tumor comes within 6.5 cm of the proximal margin and 10 cm from the distal margin, both of which are grossly free of tumor. The ileocecal valve is approximately 2 cm distal to the tumor. The mass appears to involve the wall, but not grow through it. The serosal margin over the tumor area is inked in black. The mucosa between the tumor and the ileocecal valve features a few small possible nodules that are limited to the mucosal layer and measure up to 0.4 cm. The remaining mucosa is unremarkable. Further sectioning in the area beneath the tumor/ileocecal valve area reveals a poorly defined area of white tumor/? fibrous tissue in the fat with greatest dimensions of 1.4 x 1.5 x 1.7 cm. This does not appear to be connected to the main tumor.

Final diagnosis:
Terminal ileum, appendix and colon, laparoscopic hemicolectomy -

  • neuroendocrine tumor, grade 2 (intermediate grade neuroendocrine tumor), involving terminal ileum
  • separate focus of low grade neuroendocrine tumor, grade 1, terminal ileum near ileocecal valve region
  • terminal ileum and colon resection margins, negative for neoplasm
  • lymph nodes (21), 4 positive for metastatic neuroendocrine tumor

Case Discussion

Classic example of carcinoid tumor, with relatively poor visualization of the primary tumor, which is evidenced by asymmetric nodular thickening of the terminal ileum best seen on the contrast-enhanced CT, with adjacent desmoplastic reaction/spiculation projecting into the mesentery.

What makes this case particularly striking is how subtle the finding is on the non-contrast renal stone CT. It is very easy to overlook on the axial images, but can be seen and should get one's attention when reviewing the coronal reformatted images. This case provides a great example of how multiple projections should be reviewed in every case, in order to increase opportunities to identify subtle but very important abnormalities such as this. 

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Case information

rID: 60931
Published: 9th Jun 2018
Last edited: 3rd Apr 2019
Inclusion in quiz mode: Included

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