Protein-Losing Enteropathy Caused by Ascending Colon Cancer without Polyposis: A Rare Case Diagnosed by Scintigraphy

We report a rare case of protein-losing enteropathy (PLE) caused by ascending colon cancer without associated polyposis, a clinical entity that has been scarcely documented in the literature.

A 75-year-old man presented with bilateral lower-limb edema and cellulitis, with symptoms that had gradually progressed over 1 month. Laboratory tests revealed severe hypoalbuminemia (albumin 1.2 g/dL) and elevated carbohydrate antigen 19-9 levels, while his renal and hepatic functions were preserved, excluding other common etiologies of hypoalbuminemia. Contrast-enhanced abdominal CT demonstrated a large intraluminal tumor (58 × 78 mm) in the ascending colon, and colonoscopy confirmed a nodular obstructing lesion histologically diagnosed as well-differentiated adenocarcinoma. No evidence of diffuse or syndromic polyposis was observed. Importantly, ^99mTc-labeled human serum albumin scintigraphy demonstrated focal protein leakage at the tumor site, providing strong evidence that malignancy was the direct cause of PLE. Because of profound hypoalbuminemia, a robotic right hemicolectomy was performed with the creation of a double-barreled ileostomy to minimize the risk of anastomotic leakage. The final pathological diagnosis was pT3N0M0 Stage IIa well-differentiated adenocarcinoma. The postoperative course was notable for a gradual recovery of the serum albumin level, which reached 4.0 g/dL within 4 months. Concomitantly, the peripheral edema and cellulitis resolved, reflecting the reversal of the protein-losing state. The ileostomy was successfully closed 116 days after the primary surgery, and the patient remained recurrence-free with stable serum protein levels at the 5-month follow-up examination.

To our knowledge, this is one of the few reported cases of PLE solely attributable to non-polyposis colon cancer. This case emphasizes the importance of considering PLE in the differential diagnosis of unexplained edema and hypoalbuminemia in cancer patients and highlights the diagnostic utility of albumin scintigraphy in preoperative evaluation. Furthermore, it demonstrates that prompt surgical resection can lead not only to oncological cure but also to metabolic recovery, ultimately allowing the restoration of intestinal continuity.