Infiltrative retroperitoneal metastasis causing obstructive uropathy and gastric outlet obstruction secondary to an occult sigmoid colon adenocarcinoma: a rare case report and literature review
- 1School of Medicine, Shiraz University of Medical Sciences, Shiraz, Iran
- 2Department of Surgery, Laparoscopy Research Center, Shiraz University of Medical Sciences, Shiraz, Iran
Abstract
Introduction:: Colorectal cancer most often presents with gastrointestinal problems such as obstruction and abdominal pain, or is detected early by screening colonoscopy. Retroperitoneal metastasis that mimics the findings of retroperitoneal fibrosis is rare and can cause diagnostic challenges, especially in patients in whom contrast-enhanced imaging is contraindicated.
Case presentation:: A 49-year-old woman was admitted with severe bilateral flank pain, oliguria, intermittent nausea, and loss of appetite without abdominal distention or constipation. Due to a known allergy to contrast media, a non-contrast CT scan was performed and showed bilateral hydronephrosis and evidence of retroperitoneal fibrosis. Although double-J ureteral stents were inserted, the patient’s renal function progressively deteriorated, requiring hemodialysis. After that, the patient experienced intractable vomiting, and the evaluation confirmed gastric outlet obstruction (GOO) caused by mass effect from a retroperitoneal mass. Magnetic resonance imaging findings continued to favor retroperitoneal fibrosis despite the presence of some suspicious pulmonary nodules. Surgical intervention with retroperitoneal biopsy was performed, during which an incidental sigmoid mass was detected and resected. Histopathology revealed well-differentiated sigmoid adenocarcinoma with retroperitoneal metastasis.
Discussion:: Malignancy-associated retroperitoneal fibrosis faces critical diagnostic challenges due to its radiologic findings that can mimic a benign fibroinflammatory process. Unlike previous reports that focus on retroperitoneal fibrosis in patients with known primary malignancies, this case presented without a history or symptoms of colorectal cancer. Additionally, the inability to perform a contrast-enhanced CT scan contributed to a delayed diagnosis. Failure of ureteral stenting and GOO symptoms were two main indicators of infiltrative malignant disease. Timely tissue diagnosis remains essential for atypical manifestations of retroperitoneal fibrosis.
Conclusion:: Occult sigmoid adenocarcinoma may rarely present with multi-level obstructive complications, even without typical large-bowel obstruction symptoms. Timely diagnosis and intervention require interdisciplinary collaboration to achieve critical, life-saving outcomes.
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BibTeX
@article{ali2026infiltrative,
title = {{Infiltrative retroperitoneal metastasis causing obstructive uropathy and gastric outlet obstruction secondary to an occult sigmoid colon adenocarcinoma: a rare case report and literature review}},
author = {Abdallah Abd Ali and Ali Abd Ali and Nader Moeinvaziri and Raheleh Sharifian Paghaleh},
journal = {International Journal of Surgery Case Reports},
year = {2026},
month = oct,
doi = {10.1097/rc9.0000000000001196},
url = {https://doi.org/10.1097/rc9.0000000000001196},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - Infiltrative retroperitoneal metastasis causing obstructive uropathy and gastric outlet obstruction secondary to an occult sigmoid colon adenocarcinoma: a rare case report and literature review
AU - Abdallah Abd Ali
AU - Ali Abd Ali
AU - Nader Moeinvaziri
AU - Raheleh Sharifian Paghaleh
PY - 2026
DA - 2026/10/26
JO - International Journal of Surgery Case Reports
DO - 10.1097/rc9.0000000000001196
UR - https://doi.org/10.1097/rc9.0000000000001196
AB - Introduction:: Colorectal cancer most often presents with gastrointestinal problems such as obstruction and abdominal pain, or is detected early by screening colonoscopy. Retroperitoneal metastasis that mimics the findings of retroperitoneal fibrosis is rare and can cause diagnostic challenges, especially in patients in whom contrast-enhanced imaging is contraindicated. Case presentation:: A 49-year-old woman was admitted with severe bilateral flank pain, oliguria, intermittent nausea, and loss of appetite without abdominal distention or constipation. Due to a known allergy to contrast media, a non-contrast CT scan was performed and showed bilateral hydronephrosis and evidence of retroperitoneal fibrosis. Although double-J ureteral stents were inserted, the patient’s renal function progressively deteriorated, requiring hemodialysis. After that, the patient experienced intractable vomiting, and the evaluation confirmed gastric outlet obstruction (GOO) caused by mass effect from a retroperitoneal mass. Magnetic resonance imaging findings continued to favor retroperitoneal fibrosis despite the presence of some suspicious pulmonary nodules. Surgical intervention with retroperitoneal biopsy was performed, during which an incidental sigmoid mass was detected and resected. Histopathology revealed well-differentiated sigmoid adenocarcinoma with retroperitoneal metastasis. Discussion:: Malignancy-associated retroperitoneal fibrosis faces critical diagnostic challenges due to its radiologic findings that can mimic a benign fibroinflammatory process. Unlike previous reports that focus on retroperitoneal fibrosis in patients with known primary malignancies, this case presented without a history or symptoms of colorectal cancer. Additionally, the inability to perform a contrast-enhanced CT scan contributed to a delayed diagnosis. Failure of ureteral stenting and GOO symptoms were two main indicators of infiltrative malignant disease. Timely tissue diagnosis remains essential for atypical manifestations of retroperitoneal fibrosis. Conclusion:: Occult sigmoid adenocarcinoma may rarely present with multi-level obstructive complications, even without typical large-bowel obstruction symptoms. Timely diagnosis and intervention require interdisciplinary collaboration to achieve critical, life-saving outcomes.
SN - 2210-2612
ER -