Presentation
Pelvic pain with hematochezia for 4 months.
Patient Data
A large well defined T1 isointense, T2 iso- hyperintense lobulated mass lesion in the pelvis involving the posterior left lateral rectal wall with a predominantly exophytic mass and small intraluminal component. The rectum is compressed and displaced to the right.
The prostate, seminal vesicles and urinary bladder are displaced anteriorly. The lesion is extending into left ischia-rectal fossa. The perilesional fat planes are clear. No perilesional lymphadenopathy.
As the mass is predominantly exophytic and intermediate in signal intensity a radiological diagnosis of gastro intestinal stroll tumor (GIST) was given.
Case Discussion
GIST is the most common mesenchymal neoplasm of GI tract arising from the interstitial cells of cajal. Rectal GIST is rare involving about 5% of cases.
Radiological features of GIST are: a well demarcated margins, prominent extraluminal location, no surrounding lymphadenopathy and lack of bowel lumen constriction.
The diagnosis was confirmed by histopathology and was positive for CD117.