Metaplastic papillary tumour of the salpinx: report of a case with microsatellite analysis

ABSTRACT Metaplastic papillary tumour (MPT) of the salpinx is a rare lesion found in the lumen of Fallopian tubes during the post-partum period. This lesion is very small and microscopically is composed of papillae lined by stratified epithelium. Like ovarian serous borderline tumour (BOT), epithelial elements of MPT show budding, abundant, dense and eosinophilic cytoplasm, bland nuclei or with mild atypia. It is not clear whether this lesion is a papillary metaplastic proliferation or a small atypical proliferative (borderline) serous tumour associated with pregnancy. Because of its rarity, MPT has never been investigated in molecular studies and compared with ovarian serous neoplasms. In the present study, a case tubal MPT was molecularly examined and compared with four borderline ovarian tumours (BOTs), and two low-grade (LG) ovarian carcinomas, using microsatellite analysis with 13 markers at 8 chromosomal regions involved in ovarian carcinogenesis. The tubal MPT and one of the BOTs showed no alterations in the investigated chromosomal regions. The remaining three BOTs revealed only single allelic imbalances (AI). Instead, LG serous carcinomas showed a higher frequency of alterations, including AI at chr10q23, 1p36, 9p22 and 17. In conclusion, the present study provides, for the first time, molecular data on an MPT of the Fallopian tube, revealing that this entity might share both morphologic and molecular similarities with a subset of minimally altered BOTs, termed Atypical Proliferative Serous Tumours (APSTs) which behave in a benign fashion. However, in our opinion, further molecular studies should be performed on other cases of MPTs to confirm this hypothesis.