Transverse colon foreign body-associated reactive mass mimicking gastrointestinal stromal tumors: A case report

Table 1 Timeline of clinical events

Time point	Event	Details
20 years prior	Open appendectomy	Performed for perforated appendicitis with peritonitis; no subsequent symptoms for two decades
Screening period	Screening chest CT	Incidentally detected a 9-10 cm intra-abdominal mass; patient asymptomatic
Diagnostic evaluation	Contrast-enhanced abdominal CT	Well-circumscribed mass with central low attenuation and peripheral enhancement, strongly suggestive of a GIST
Day of surgery	Exploratory laparotomy	Dense adhesions present; mass originated from the transverse colon rather than the small bowel
Same operation	Segmental transverse colectomy	Mass and involved colon resected; stapled functional end-to-end anastomosis performed
Postoperative day 7	Initial discharge	Early recovery uneventful
Postoperative day 8	Readmission	Nausea and vomiting; imaging suggested postoperative ileus; managed conservatively
Postoperative day 13	Final discharge	Symptoms resolved; no further complications
Postoperative pathology	Final diagnosis	Well-circumscribed 9.7 cm × 8.0 cm × 7.5 cm subserosal mass arising from the transverse colon; unilocular cystic lesion with a thick fibrous capsule, containing necrotic debris and old hemorrhage. No epithelial lining or neoplastic cells identified. Histology demonstrated cholesterol crystals and chronic foreign body-type inflammatory reaction, with PAS-positive irregular foreign materials detected microscopically, despite no grossly identifiable foreign material

CT: Computed tomography; GIST: Gastrointestinal stromal tumor.