Abstract
Background
Collision tumors are defined as the juxtaposition of two histologically distinct tumors, which form a single mass, without histological mixing of the two tissues. They are extremely rare, especially in the digestive tract.
Clinical presentation
An 81-year-old patient was admitted for anemia, diarrhea and palpable abdominal mass. The colonoscopy showed a substenosing tumor of the transverse colon. On abdominal CT, the colonic mass invaded the stomach. After surgical treatment with transverse colectomy and associated partial longitudinal gastrectomy, pathological results showed that it was a collision between a primary gastric adenocarcinoma and a primary colonic adenocarcinoma.
Conclusion
We report a first case of collision tumor between a primary gastric adenocarcinoma and a primary colonic adenocarcinoma. Current knowledge on the subject is extremely limited.
Disclosure statement
No potential conflict of interest was reported by the author(s).