Case presentation

A 90-year-old woman with a history of chronic heart failure, paroxysmal atrial fibrillation, and chronic kidney disease was brought to our emergency department 13 days before the endoscopic procedure with sudden-onset dyspnea and generalized weakness. She was admitted to the cardiology ward with acute exacerbation of chronic heart failure and improved gradually with standard medical management. Plain abdominal computed tomography (CT) on admission incidentally revealed a colonic mass suspicious for malignancy; given her advanced age, further workup was initially deferred.

Thirteen days after admission, on the day of endoscopy, she developed persistent poor oral intake and recurrent vomiting, prompting gastroenterology consultation. Repeat CT confirmed a transverse colon tumor near the hepatic flexure causing complete large bowel obstruction with marked proximal colonic distension (Figure 1). Contrast-enhanced CT was withheld because of chronic kidney disease; unenhanced CT showed no obvious distant metastasis. Laboratory investigations revealed marked leukocytosis (white blood cell count 20,590/µL) and elevated C-reactive protein (3.79 mg/dL), consistent with obstructive colitis (Table 1). Given her high surgical risk attributable to cardiac and renal comorbidities, advanced age, and nutritional status, endoscopic SEMS placement was selected as the primary intervention.

Figure 1: Unenhanced axial computed tomography image of the abdomen obtained on admission.Unenhanced axial computed tomography (CT) image of the abdomen obtained on admission, showing a circumferential mass (arrow) at the hepatic flexure of the transverse colon with marked mural thickening and irregular intraluminal morphology. The lesion caused near-complete large bowel obstruction with pronounced dilatation of the proximal colon. Contrast-enhanced CT was withheld because of underlying chronic kidney disease. No extraluminal gas or free fluid was identified, excluding perforation.

Parameter | Value | Reference range | Unit | Flag
Total protein | 6.0 | 6.6–8.1 | g/dL | L
Albumin | 2.4 | 4.1–5.1 | g/dL | L
Total bilirubin | 0.5 | 0.4–1.5 | mg/dL | 
AST | 23 | 13–30 | IU/L | 
ALT | 29 | 7–23 | IU/L | H
LDH | 364 | 125–220 | IU/L | H
CK | 71 | 41–153 | IU/L | 
BUN | 21.7 | 8.0–20.0 | mg/dL | H
Creatinine | 1.95 | 0.46–0.79 | mg/dL | H
Uric acid | 6.9 | 2.6–5.5 | mg/dL | H
Sodium (Na) | 137 | 138–145 | mmol/L | L
Potassium (K) | 2.9 | 3.6–4.8 | mmol/L | L
Chloride (Cl) | 105 | 101–108 | mmol/L | 
C-reactive protein | 3.79 | <0.14 | mg/dL | H
WBC | 20,590 | 3,300–8,600 | /µL | H
RBC | 3.86 | 3.86–4.92 | ×10⁶/µL | 
Hemoglobin | 11.5 | 11.6–14.8 | g/dL | L
Hematocrit | 35.2 | 35.1–44.4 | % | 
Platelet count | 334 | 158–348 | ×10³/µL | 
MCV | 91.2 | 84.0–98.0 | fL | 
MCH | 29.8 | 28.0–33.0 | pg | 
MCHC | 32.7 | 32.0–35.0 | % | 

Colonoscopy was performed the same day with a standard colonoscope (PCF-H290I; Olympus, Tokyo, Japan). Bowel preparation consisted of a retrograde warm-water enema (300 mL) alone, a pragmatic choice given the patient’s hemodynamic fragility and complete obstruction. During insertion, loops were reduced as needed under fluoroscopic guidance, and the transverse colon was loop-free at the time of stent deployment; scope stability was nonetheless poor, because the endoscope was pushed back whenever it was advanced toward the tumor, limiting transmission of force to the catheter tip. Colonoscopy revealed a circumferential, friable, ulceroproliferative tumor near the hepatic flexure (Figure 2) producing a near-complete stenosis that did not admit the colonoscope. The residual lumen was eccentric and only barely traversable by a guidewire, and, owing to the acute flexure angulation, its axis ran tangential to the endoscopic line of approach, so that the orifice could not be visualized fully en face.

Guidewire passage was first attempted with a 0.035-inch angled-tip hydrophilic guidewire (Jagwire; Boston Scientific, Marlborough, MA) delivered through a standard ERCP catheter (MTW Endoskopie, Wesel, Germany). Despite catheter torque, repeated re-angulation of the guidewire tip by torque, and patient repositioning, the catheter tip could not be brought coaxial with the eccentric orifice and the guidewire could not be advanced across the stricture. Exchange for a differently shaped catheter was not attempted; instead, the catheter was exchanged for a rotatable sphincterotome (ENGETSU; Kaneka Medix, Osaka, Japan).

Figure 2: Endoscopic view of the transverse colon tumor.A circumferential, friable, and ulceroproliferative tumor (white arrow) is observed near the hepatic flexure, with an adherent blood clot (black arrow) on its surface.

The cutting wire was not connected to an electrosurgical unit and was not activated at any point; the device was used solely for mechanical tip steering, eliminating any risk of thermal injury to the colonic wall. By adjusting handle rotation and tip bending, the tip was directed toward the eccentric orifice, and the guidewire was advanced across the stricture under fluoroscopic guidance (Figures 3-5). Fluoroscopic measurement by catheter withdrawal confirmed an obstruction length of approximately 90 mm. Over the guidewire, an uncovered 22 mm × 120 mm Niti-S colonic SEMS (Taewoong Medical, Seoul, South Korea) was deployed using the over-the-wire technique under combined endoscopic and fluoroscopic guidance, fully covering the stricture; the 120 mm length provided a 30 mm margin beyond the 90 mm stenosis. Complete deployment was confirmed fluoroscopically, with immediate satisfactory fecal effluent confirming luminal patency. The total procedure time was 63 minutes and the fluoroscopy time was 23 minutes. No immediate adverse events occurred.

Figure 3: The rotatable sphincterotome and its tip-control mechanism.(A) Tip bending achieved by tensioning the cutting wire through handle manipulation. (B) Return to the straightened configuration by releasing wire tension. (C) Overview of the complete device, showing the rotatable handle assembly and catheter shaft. (D) Sequential positions of the catheter tip demonstrating 360-degree circumferential reorientation achieved by rotating the handle, illustrating the multiplanar directional control of the device.

Figure 4: Sequential endoscopic images documenting the stepwise progression from guidewire failure to successful stent deployment.(A) En face view of the malignant stricture at the hepatic flexure. The eccentric residual luminal orifice (arrow) is deviated out of the axial plane accessible to the standard catheter, which could not be inserted coaxially despite repeated attempts and patient repositioning. (B) The rotatable sphincterotome was introduced through the working channel of the colonoscope; incremental handle rotation and tip-bending adjustment directed the catheter tip coaxially into the eccentric orifice, allowing the guidewire to be advanced through the stricture under fluoroscopic guidance. (C) A 22 mm × 120 mm uncovered Niti-S colonic self-expandable metal stent (SEMS) delivery system (Taewoong Medical, Seoul, South Korea) was advanced over the guidewire into the malignant stricture using the over-the-wire technique. (D) Fully deployed 22 mm × 120 mm uncovered Niti-S colonic SEMS covering the stricture.

Figure 5: Sequential fluoroscopic images confirming guidewire passage and stent deployment at the hepatic flexure.(A) After successful use of the rotatable sphincterotome, the guidewire has traversed the malignant stricture and its tip lies well within the ascending colon. (B) The 22 mm × 120 mm uncovered Niti-S colonic self-expandable metal stent (SEMS) delivery system (Taewoong Medical, Seoul, South Korea; arrow) advanced over the guidewire across the stricture. The 120 mm length was selected to provide a 30 mm safety margin beyond the fluoroscopically measured 90 mm obstruction. (C) Fully deployed 22 mm × 120 mm uncovered Niti-S colonic SEMS at the hepatic flexure, with adequate radial expansion and complete coverage of the stricture.

Postprocedure CT on day 1 confirmed correct stent positioning at the hepatic flexure, with adequate expansion and relief of the proximal distension (Figure 6). The patient resumed oral intake on postprocedure day 1. Biopsy confirmed well-to-moderately differentiated adenocarcinoma (Figure 7). After multidisciplinary discussion and in accordance with the wishes of the patient and her family, and given her advanced age, frailty, and the absence of radiological evidence of distant metastasis, aggressive antineoplastic therapy was not pursued, and a best-supportive-care plan was established. No recurrent obstruction occurred, and no reintervention was required. After a course of physical rehabilitation, she was transferred to a long-term care facility on postprocedure day 29 in stable condition; follow-up ended at that transfer, with no subsequent contact.

Figure 6: Unenhanced axial computed tomography image obtained on postprocedure day one.Unenhanced axial computed tomography (CT) image obtained on postprocedure day one, showing the uncovered Niti-S colonic self-expandable metallic stent (arrow) correctly positioned at the hepatic flexure. The stent is expanded across the malignant stricture with no evidence of migration or perforation. In direct comparison with the preprocedure CT (Figure 1), the marked proximal colonic dilatation has substantially resolved, confirming successful luminal decompression.

Figure 7: Photomicrograph of a biopsy specimen from the transverse colon tumor (hematoxylin and eosin stain; original magnification ×200).Atypical columnar epithelium proliferates in a complex, irregularly branching tubular architecture with loss of normal glandular polarity. The nuclei are markedly enlarged, hyperchromatic, and pleomorphic, ranging from elongated spindle-shaped to rounded oval forms, with stratification and focal loss of basal orientation. These features are diagnostic of well-to-moderately differentiated adenocarcinoma.