Case of the week Details

• A well-defined, intraluminal, hyperenhancing, rounded mass measuring 2.2 x 3.4 x 2.5cm (in AP X TR X CC) is noted within the proximal ileum. 
• Multiple enhancing lymph nodes are seen in the root of the small bowel mesentery. Significant surrounding desmoplastic reaction is noted in the form of mesenteric stranding. This causes tethering of the adjacent bowel loops and dilatation of the jejunal loop.

DIAGNOSIS

•  Neoplastic intraluminal mass within the proximal ileum with likely metastatic mesenteric lymph nodes and small bowel obstruction. A neuroendocrine aetiology is likely.

DISCUSSION

• Well-differentiated neuroendocrine tumor usually originating in digestive tract. 
• Carcinoid tumor arises from the chromaffin cells at the base of the crypts of Lieberkühn.
• It most frequently arises in the distal ileum, Meckel diverticulum, or appendix and can be multifocal.
• Detection of primary carcinoid tumor in the small bowel is difficult -small size of the primary tumor (often less than a centimeter) and its location in the submucosa.
• More often, a spiculated mesenteric mass from metastatic disease is detected with imaging.
• The mesenteric mass may contain calcifications and often shows desmoplastic reaction.
• Desmoplastic reaction: Finger-like projections of mass into adjacent mesentery.
• This mass can stimulate a fibrotic reaction in the surrounding tissues and lead to bowel obstruction, ischemia, or vascular compromise. 
  Liver metastases:
       -Arterial phase: Intense enhancement (↑ vascularity)
       -Delayed imaging: Iso - to hypodense to liver
• Gallium-DOTATATE PET/CT: Localization of somatostatin receptor-positive NETs.
• Identification of primary tumor in patients with known metastatic disease.

References

• https://doi?org/10?1148/rg?2020200011

DR VIKHYATH SHETTY
Consultant radiologist
Manipal hospital, Yeshwanthpur, Bengaluru.

DR NEHA SATHYANARAYANA
Radiology resident 
Manipal hospital, Yeshwanthpur, Bengaluru.