Borderline and malignant serous tumor arising in pelvic lymph nodes: evidence of origin in benign glandular inclusions.

This report describes two cases of malignant serous cancers with areas of borderline malignancy, which appear to have arisen within benign glandular inclusions of coelomic origin in pelvic or para-aortic lymph nodes. The patients were 44 and 62 years of age. In both cases the nodes contained benign glandular inclusions lined by a single layer of epithelium which resembled that of tubal epithelium. The location of the glandular epithelium varied from within the fat near the node to intracapsular, subcapsular, or interfollicular positions. The number of glands ranged from few to extensive. In both cases the glandular inclusions disclosed epithelial proliferations, ranging from minor degrees of stratification with formation of small papillae of atypical cells (borderline serous tumor) to almost solid tumor typical of serous cancer. In both cases, the borderline and cancerous tumors exhibited areas of transition which appeared to arise from benign glands. Although benign glandular inclusions of coelomic origin are well documented to occur in pelvic or para-aortic lymph nodes of 5-20% of women and have been considered to be of significance only because of the possibility of the misdiagnosis of cancer, it should now be recognized that the glandular inclusion cysts themselves can become neoplastic.