Case Presentation R.V.S.N., 58 years old, presented to the emergency room with a 4-day history of abdominal
pain, absence of bowel movements, and vomiting. Physical examination revealed abdominal
distension and diffuse tenderness upon palpation. An abdominal CT scan showed significant
distension of the small intestine and descending colon with adjacent fat stranding.
A large multiloculated solid-cystic lesion measuring 15 cm at its largest diameter
was identified, causing upstream obstruction. The liver and lungs showed no lesions
suggestive of metastasis. The patient underwent exploratory laparotomy, revealing
a stenosing tumor of the sigmoid colon. A Hartmann's procedure was performed, and
the surgical specimen was sent for biopsy. Pathological examination revealed a moderately
cellular mesenchymal neoplasm with an immunohistochemical profile consistent with
a gastrointestinal stromal tumor (GIST). Clinical follow-up was chosen, with no need
for adjuvant therapy.
Discussion GISTs account for approximately 0.1–3% of colorectal cancers. They originate from
Cajal cells and pluripotent stem cells of the mesenchyme. Histologically, they exhibit
spindle-shaped cells and are positive for the CD117 and CD34 antigens in 60–70% of
cases. GISTs are most common in the 6th and 7th decades of life and affect both sexes
equally. They grow slowly and are often incidental findings. Common symptoms include
hematochezia and abdominal pain. GISTs can metastasize to the liver and peritoneum,
though lymph node involvement is rare. Diagnosis is typically made via colonoscopy.
CT and MRI are used for staging and to assess surgical resectability. Surgery is the
treatment of choice, with at least a 1 cm margin required. Lymphadenectomy is unnecessary.
Imatinib can be used as adjuvant therapy for incomplete surgical resections and metastatic
disease, reducing recurrence risk. It is also employed as neoadjuvant therapy for
initially unresectable tumors to reduce their size. Recurrence and metastasis occur
in up to 50% of cases.
Conclusion Despite the low incidence of GISTs in the colon and rectum, they should be considered
as differential diagnoses in cases of intestinal obstruction. GISTs respond well to
Imatinib in combination with surgical resection. Encouraging colorectal cancer screening
through colonoscopy is vital for early diagnosis and better prognoses.
