A 66 year old woman has profuse watery diarrhea which has lasted more than 6 weeks. Thediarrhea does not improve when oral intake is limited. She has had a 5 pound weight loss. She
drinks two glasses of wine nightly. All stool cultures are negative. Fecal leukocytes are negative.
A Sudan stain performed on a stool specimen is negative. The D-Xylose test shows 10 grams of
xylose in the urine. Stool electrolytes are checked: stool sodium concentration is 85mmol/l and
stool potassium concentration is 50mmol/l.
Which of the following is the most likely diagnosis?
