Mastocytosis and intestinal malabsorption

Abstract

Malabsorptive defects in association with systemic mastocytosis were studied in a sixty-one year old woman. Malabsorption of carbohydrates, fat and vitamin B, indicated involvement of the entire small bowel. Surgical small bowel biopsy disclosed abnormal numbers of mast cells beneath the muscularis; a rectal biopsy disclosed abnormal numbers of mast cells in the lamina propria and submucosa. Per oral small bowel biopsy showed intense mucosal and submucosal round cell infiltrates containing large numbers of eosinophils. High titers of antibodies to gluten (fraction Ill), alpha lactalbumin and beta lactoglobulin indicated transmucosal passage of incompletely degraded food antigens. Sensitivity to gluten was demonstrated by a favorable response to a gluten-free diet, and prompt exacerbation of steatorrhea and diarrhea following gluten challenge. This was considered to be secondary to mast cell invasion of the gastrointestinal tract rather than adult celiac disease unmasked by systemic mastocytosis. On a daily fat intake of 100 gm incorporated into a gluten-containing diet, the attacks of facial flushing, abdominal pain, tachycardia and explosive diarrhea ceased. This occurred coincident with a decrease in serum magnesium: restoration of magnesium levels to normal was followed by a recurrence of attacks. It was inferred that hypomagnesemia may promote degranulation and/or prevent regranulation of mast cells in man. Although the symptoms were similar to those observed in other patients with mastocytosis, urinary histamine levels were normal. Histidine loading did not enhance symptoms or increase histaminuria above that of control subjects.