Villous Adenoma

An epithelial neoplasm morphologically characterized by the presence of a villous architectural pattern. Most often it occurs in the large intestine, small intestine, and the stomach in which the neoplastic epithelial cells show dysplastic features. It may also arise in the urinary bladder, urethra, and vagina.


Report of a Case
An 82-year-old woman was admitted to the hospital with syncopal attacks. Over the preceding months she had noticed increasing weakness, malaise, and a 15-pound weight loss. She described passage of "urine per rectum" for the previous six years. Two days before admission she had fallen four times, with brief loss of consciousness.
Examination revealed an alert, young-appearing 82-year-old woman. Blood pressure was 132/80 mm Hg and pulse regular at 100 per minute. The patient was not dehydrated, and the only physical finding was a very soft rectal mass. She was considered to be having transient ischemic attacks, and was given sulfinpyrazone.
The syncopal attacks were now thought to be due to hyponatremic hypovolemia and postural hypotension. Since urinary sodium was low, sodium and water depletion was considered likely to be due to gastrointestinal loss. Attention now focused on "urine in the rectum," which made it necessary for the patient to use a perineal pad. She occasionally passed bright red blood per rectum.
Sigmoidoscopy revealed a circumferential, friable, actively secreting villous adenoma from the pectinate line proximally to 13 cm. Rectal fluid volume was 1,500 ml in 24 hours. The sodium concentrations of this fluid, measured on two occasions, were 149 and 122 mEq/1, potassium 16 and 36 mEq/1, and chloride 123 and 127 mEq/1. After infusion of 4,300 ml physiologic saline solution in 24 hours, the patient recovered from her somnolent state, and postural hypotension disappeared. The hematocrit decreased to 29 per cent and two units of packed cells were administered.
Once resuscitated, the patient underwent transsphincteric submucosat excision of the giant villous adenoma with primary coloanal mucosal anastomosis and repair of the sphincter (Fig. 1). The

Discussion
Villous adenoma is commonly associated with potassium deficiency, yet few patients have symptomatic hypokalemia, l'10'1a't~ Hyponatremia is present in many reported cases, but physicians tend to emphasize potassium depletion in relation to these tumors, t'4"5,s'a5 In our case and two others, serum potassium was nearly normal, but sodium depletion was severe. 4"9 Wrong and Metcalfe-Gibson tT determined the electrolyte content of stool by having healthy volunteers swallow dialyzing bags filled with an inert colloid solution. During transit through the colon, the contents of these bags reach equilibrium with the stool. Analysis of the fluid in the bags after expulsion is a measure of stool electrolyte concentration. The mean sodium concentration of normal stool was found to be 31.6 mEq/1 (range 4.4-112 mEq/1), and the potassium concentration was 75 mEq/1 (range 29-147 mEq/1). Devroede and Phillips 5 demonstrated that the normal human colon conserves sodium and water, whereas it actively secretes potassium and bicarbonate, t2 Potassium concentrations of tumor secretions range from 15 to 107 mEq/1 (average 44 mEq/1)? This is 10 to 20 times greater than serum concentration,l~,16 but similar to that of normal stool water. In the present case, stool potassium was 16 and 36 mEq/1. On the other hand, the sodium concentrations of tumor secretions range from 100 to 282 mEq/1 (average 120 mE@l), greater than that usually found in stool, t6 The patient presented here had sodium concentrations of 122 and 149 mEq/1 in the rectal discharge. Thus, villous adenomas secrete sodiumrich fluid and potassium loss is due to the large vol-0012-3700-78-0300--0118 $00.