Histochemical study of mucinous ovarian cystomas of intestinal and mixed types: O-acetylated sialomucin content in relation to biologic behavior.

The subgroup of mucinous ovarian cystomas of intestinal type containing site 8 O-acetylated sialomucins and its relation to malignant behavior were studied. Of 75 mucinous cystomas of the ovary from the files of the Institute of Pathological Anatomy and Histology (University of Genoa), 54 were endocervical, 19 were mixed, and 2 were intestinal. As regards their histologic pattern, the 54 mucinous endocervical cystomas were benign, whereas the 19 mixed type group included 8 benign, 5 borderline and 6 malignant; the 2 intestinal type tumors were borderline. According to histochemical investigations, the frequency of tumors with goblet cells containing site 8 O-acetylated sialomucins (positive to PB/KOH/PAS) was 47% in the mixed type cystomas and 100% in the intestinal type cystomas. Twenty-five percent of benign mixed cystomas, 60% of borderline mixed cystomas, and 67% of mixed cystadenocarcinomas were positive to PB/KOH/PAS. One hundred percent of the borderline cystomas of intestinal type were positive. Our results confirm that among mucinous ovarian cystomas, those containing intestinal type epithelium are the most likely to fall within the borderline or malignant categories. Moreover, of all ovarian cystomas of intestinal type, those characterized by site 8 O-acetylated sialomucins seem to be more aggressive and, in general, to have a more malignant behavior than the mucinous cystic tumors of müllerian or endocervical type.