A new syndrome of symptomatic cutaneous mastocytoma producing vasoactive intestinal polypeptide.

An 8-mo-old male child presented with generalized flushing and apnea which followed irritation of a 1.5 x 0.5 cm cutaneous mastocytoma on the left upper arm. Peripheral venous blood samples were drawn before and after manipulation of the tumor, immediately after excision, and again 30 days later. The plasma vasoactive intestinal polypeptide level before excision was high (345 pg/ml) and was accompanied by low acid secretion (15.4 mEq/L) and hypergastrinemia (209 pg/ml), all of which returned to normal after excision of the tumor (50 pg/ml, 35.7 mEq/L, and 131 pg/ml, respectively). Serum histamine levels were undetectable. Histology of the tumor showed only mast cells and no enterochromaffin tissue. The immunoreactive vasoactive intestinal polypeptide content of the tumor was 28 ng/g wet wt and the extracted vasoactive intestinal polypeptide was immunologically indistinguishable from natural porcine vasoactive intestinal polypeptide. The child has remained asymptomatic postoperatively. We conclude that the symptoms associated with this mastocytoma may have been produced by oversecretion of vasoactive intestinal polypeptide and not histamine.