[Histogenetic considerations on mucinous cystomas of the ovary based on histochemical and immunohistochemical findings].

Mucinous cystomas of the ovary, according to a new proposed classification (I.A.P., Dublin 1988), are classified in three types: endocervical, intestinal and mixed. Their histogenesis is still controversial, thus requiring further investigations. There are two main theories on this matter: a teratomatous theory based on the assumption that the mucinous cystoma is allegedly a teratoma having a monophyletic development where only the endodermal gastrointestinal component remains. The second theory, currently the most widely accepted one, maintains that mucinous cystomas derive from Muller duct residues or, more generally, from introflections of the coelomic epithelial lining through a Muller-type metaplastic process. Some authors also accept both theories. A group of 117 mucinous cystomas were investigated by histochemical methods (PB/KOH/PAS; PAT/KOH/Bh/PAS), to demonstrate the presence of O-acetylated sialomucin variants in goblet cells of intestinal type component. Endocervical type mucinous cystomas have always presented as PB/KOH/PAS negative, whereas mixed type mucinous cystomas presented as positive according to the following percentage: benign forms, 31%; borderline, 67%; malignant, 50%. These data should confirm the hypothesis that intestinal type cystomas may derive from the surface coelomic epithelium of the ovary, through a gastrointestinal metaplastic process. This hypothesis is further supported by the data obtained from the observation on two cases of intestinal metaplasia of endocervical glands, kindly supplied by Dr. Trowell. In one of them, a weak O-acetylated sialomucin secretion was identified, in addition to the presence of argentaffin cells. Furthermore, out of 38 adenocarcinomas of the endometrium and 15 adenocarcinomas of the endocervix, one case of endocervical adenocarcinoma was found, characterized by a mucous secretion rich in O-acetylated sialomucins. Moreover, immunohistochemically, by means of anti-chromogranin A monoclonal antibodies, endocrine cells were found in benign, borderline and malignant mucinous cystomas of mixed type. These data do not seem to confirm the assumed correlation between neuroendocrine cell presence and biologic behaviour of the neoplasm nor do they clarify tumor histogenesis. Another immunohistochemical study with BD5 monoclonal antibody demonstrated that this marker was present in the intestinal type epithelium of mixed mucinous cystomas. The histogenetic teratomatous hypothesis of ovarian mucinous cystomas was confirmed by reviewing 100 ovarian teratomas, in which O-acetylated sialomucins were found in the epithelial component of one mucinous carcinoid and in the intestinal type epithelium of 9 mature cystic teratomas.(ABSTRACT TRUNCATED AT 400 WORDS)