Leiomyosarcoma of the jejunum, pathology-proven. No metastases were detected.

Leiomyosarcoas account for approximately 10% of the small-bowel malignancies. Although they may occur anywhere in the small intestine, the duodenum is less commonly affected (in contrast to adenocarcinoma). 

Tumor characteristics:

• the main site of predilection is the ileum (50%). 
• most tumors are larger than 6 cm
• 66% show extraluminal growth. As a result bowel obstruction is somewhat unusual or reflects a late tumor stage. 
• leiomyosarcomas are rarely asymptomatic and are clinically manifested by abdominal pain and melena. 
• intraperitoneal hematogenous seeding is common, where lymphogenous metastases are rare.

MRI specifics:

• comparable to leiomyoma: 
  • rounded and well-circumscribed
  • submucosally located
  • 1-10 cm in diameter
  • intermediate signal intensity on T1
  • slighly increased signal on T2
  • homogeneous moderate to high contrast enhancement
  • signal voids can be caused by calcifications
  • zones of tumor necrosis may produce map-like hypointense areas on T1 after contrast
  • irregular lesion margins and enlarged lymph nodes should raise a suspicion of leiomyosarcoma
• MRI is better than enteroclysis for detecting eccentric tumor components
• MRI can also detect cystic metastases in the peritoneal cavity and liver

Tumors of the small intestine