Intussusception caused by metastatic renal cell carcinoma at the duodenojejunal junction 41 years after nephrectomy: a case report.

INTRODUCTION AND IMPORTANCE: Renal cell carcinoma (RCC) is known for its potential for late recurrence; however, ultra-late recurrence occurring more than four decades after nephrectomy is extremely rare. Small-bowel metastasis causing intussusception is also uncommon. CASE PRESENTATION: A 73-year-old man underwent right nephrectomy for RCC 41 years earlier. He was referred to our hospital because of rapidly worsening glycemic control. Contrast-enhanced computed tomography (CT) revealed two hypervascular pancreatic tumors and a hypervascular small-bowel mass near the ligament of Treitz. Multiple distant metastases from recurrent RCC were suspected. Endoscopic ultrasound-guided fine-needle aspiration and endoscopic biopsy were inconclusive. One week later, the patient developed abdominal pain and vomiting. Repeat CT revealed intussusception of the proximal jejunum caused by the small-bowel tumor, requiring surgical intervention. Partial resection of the duodenojejunal junction with bypass procedures was performed. Histopathological and immunohistochemical examination revealed metastatic RCC. CLINICAL DISCUSSION: RCC may recur even decades after nephrectomy, and atypical metastatic sites such as the small intestine should be considered. Adult intussusception is rare and often associated with an underlying malignant lesion. CONCLUSION: This case highlights that RCC can recur as small-bowel metastasis even more than four decades after nephrectomy and may present as intussusception.