P3700 - A Rare Case of Spindle Cell Carcinoma of the Transverse Colon

Mikaella Baliwag, ¹, Priyanka Yaramada, MD^2
1Ideal Gastro Associates, Diamond Bar, CA; ²Ideal Gastro Associates/San Antonio Regional Hospital, San Dimas, CA

Introduction: Spindle cell or sarcomatoid carcinoma of the colon is extremely rare and aggressive with few reported cases worldwide. It has both mesenchymal and epithelial components that can involve the upper gastrointestinal tract, but primary colon origin is quite uncommon and has poor prognosis. This tumor diagnosis is confirmed through histology and immunostaining.

Case Description/Methods: A 58-year-old male presented to the emergency room for worsening fatigue and weight loss in the past few months. Labs showed iron deficient anemia and hemoglobin of 8.1 on admission. Comprehensive metabolic panel was normal. CEA level was 0.98. CT abdomen and pelvis revealed intussusception of transverse colon with a suspected 5 cm mass. Further investigation with colonoscopy confirmed a large, non-obstructive mass of the transverse colon, at 75 cm from the anal verge. Pathology showed necroinflammatory tissue with focal atypical stromal cells. The patient underwent laparoscopic to open transverse colectomy. The final surgical pathology revealed an intermediate-grade, NTRK-rearranged spindle cell carcinoma with surgical margins negative for malignancy. There were twenty-three lymph nodes resected that were negative for metastasis. The patient recovered well and was discharged with an oncology follow-up.

Discussion: Spindle cell or sarcomatoid carcinoma is a very aggressive tumor with a challenging diagnosis and poor patient outcome. Despite its rarity, a differential diagnosis of sarcomatoid carcinoma should not be missed with endoscopic pathological diagnosis. Immunostaining with cytokeratin and vimentin should be performed to confirm the diagnosis, which was initially not done in this case for endoscopic tissue diagnosis.



Disclosures:


Mikaella Baliwag, ¹, Priyanka Yaramada, MD². P3700 - A Rare Case of Spindle Cell Carcinoma of the Transverse Colon, ACG 2024 Annual Scientific Meeting Abstracts. Philadelphia, PA: American College of Gastroenterology.