Pseudomyxoma Peritonei: A Rare Cause of Oliguric Acute Kidney Injury
A 53-year-old man presented to the emergency department with poor oral intake and abdominal distension. He had been admitted to other hospitals with abdominal distention twice over the previous year, at which time abdominal CT had shown moderate ascites. He underwent gastroduodenoscopy and colonoscopy to rule out gastrointestinal malignancy, but the results were unrevealing. He refused further evaluation at that time and had stopped seeking conventional medical care in favor of alternative medicine. At the present admission, he complained of a 5-kg weight loss over the previous month and intermittent vomiting for several weeks. The physical examination revealed a tense, distended abdomen with no palpable mass. His blood pressure was 110/70 mmHg and his pulse was 92 beats/minute. His mucous membranes were dry, his skin turgor was poor, and his initial urine output was less than 10 ml/hour for 12 hours. Laboratory evaluation showed severe azotemia (blood urea nitrogen, 66.3 mg/dl [normal range, 3-23 mg/dl]; creatinine, 2.86 mg/dl [normal range, 0.3-1.6 mg/dl]), decreased serum sodium and chloride (Na, 130 mmol/L [normal range, 133-146 mmol/L]; Cl, 85 mmol/L [normal range, 99-110 mmol/L]), and decreased urine sodium and chloride (Na<10 mmol/L, Cl<10 mmol/L). The fractional excretion of sodium was reduced to 0.1%. Tumor markers were elevated: CEA was 25.0 ng/ml (normal range, 0-5 ng/ml) and CA 19-9 was 142.6 IU/ml (normal range, 0-37 IU/ml). Other biochemical findings were normal. A chest x-ray showed subsegmental atelectasis of both lower lungs. His creatinine level was markedly elevated compared with the last level of 0.9 mg/dl measured 9 months previously and continued to rise steadily up to 3.4 mg/dl at 48 hours after admission. The findings were consistent with AKI as defined by the Acute Dialysis Quality Initiative group.\nOwing to the patient's volume depletion, we initiated volume resuscitation with normal saline (4 L/day). His urine output did not improve, however, so we obtained a non-contrast CT of the abdomen, which revealed massive ascites of the abdomen and pelvis, diffuse peritoneal thickening, infiltration of the greater omentum, and hydronephrosis and hydroureter of the right kidney without an obstructing lesion in the urinary tract (). Ultrasound-guided paracentesis yielded thick mucoid pus. A pigtail catheter was placed but was unable to drain the extremely thick fluid. Owing to the progression of azotemia and metabolic acidosis, a right percutaneous nephrostomy was performed, yielding urine amounts of less than 100 ml per day, which had no effect on the progressive kidney injury. The following day, after several attempts to irrigate, the pigtail catheter allowed nearly 4 L of thick ascites to drain, after which urine output increased to 2.7 L in 24 hours () and creatinine dropped to 1.16 mg/dl. The follow-up CT with contrast is shown in . Unfortunately, the patient's symptoms did not improve along with restoration of his renal function. Accordingly, gastroduodenoscopy and colonoscopy were performed, which showed chronic gastritis and several colon polyps that were biopsied and found to be tubulovillous adenomas with high-grade dysplasia. Exploratory laparoscopy confirmed massive mucin-rich ascites suggestive of PMP.\nDebulking surgery was performed to remove the mucinous ascites. Histopathologic findings of samples from the cystic wall and peritoneum of the ascending colon confirmed the diagnosis of PMP and mucinous cystadenoma. The findings of the surface encased with mucus and mucinous epithelium with minimal atypia indicated low-grade PMP () and immunohistochemistry was positive for cytokeratin 20 and negative for cytokeratin 7, which suggested an origin of the lower gastrointestinal tract ().