[Gatrointestinal stromal tumor: a case report].

Area of Science:

• Gastroenterology
• Surgical Oncology
• Pathology

Background:

• Gastrointestinal stromal tumors (GIST) are the most common mesenchymal neoplasms of the GI tract.
• Preoperative diagnosis of GIST is challenging, with up to 5% presenting as pelvic masses.

Observation:

• A 45-year-old patient presented with unspecific lower abdominal pain.
• Abdominopelvic tomography revealed a 9x8 cm pelvic mass, initially suspected as an abscess.
• Emergency laparotomy identified a 14 cm small intestine tumor without ascites or other organ involvement.

Findings:

• Pathological analysis confirmed a 14 cm GIST with central cavitation.
• Histology showed epithelioid cells, low mitosis (1-2/5 mm2), strong DOG-1, focal CD117, and low Ki67.
• Molecular testing revealed a c-kit gene mutation (exon 11, p.W557_K558del).

Implications:

• This case underscores the importance of considering GIST in pelvic masses, even when presenting atypically.
• Successful surgical excision followed by imatinib therapy demonstrates effective management for localized GIST.
• Accurate diagnosis through immunohistochemistry and molecular pathology is crucial for targeted therapy and improved patient outcomes.