Predominance of sialomucin secretion in malignant and premalignant pancreatic lesions.

Sialomucin and sulphomucin-secreting cells were studied in the normal and pathologic human pancreas with the high iron diamine-alcian blue technique which allows differentiation between the two types of mucin. In six normal autopsy pancreata, only sulphomucin was found. In benign lesions of either calcifying chronic pancreatitis (seven cases) or obstructed chronic pancreatitis (six cases), sulphomucins were widely predominant. In contrast, malignant lesions (pancreatic adenocarcinoma [12 cases], cystadenocarcinoma [two cases]) or premalignant lesions (mucinous cystadenoma [one case], ductectatic mucinous cystadenoma [four cases], villous adenoma of the main pancreatic duct [two cases]) showed a predominant sialomucin secretion, except for three poorly differentiated pancreatic carcinomas that did not show mucin staining. The sialomucin positivity was not observed at distance from the malignant lesions. In one case of benign enteroid cyst, sulphomucins predominated. These findings indicate a preponderance of sialomucin secretion in malignant or premalignant pancreatic lesions.