Benign glandular inclusions of the peritoneum and periaortic lymph nodes.

A rare case of benign glandular inclusions is described involving the peritoneum and periaortic lymph node simultaneously. Some of the inclusions appeared as solid cell nests or cribriform glands, which let to the initial misinterpretation of metastatic adenocarcinoma in an appendectomy specimen. The concomitant involvement of the peritoneum and periaortic nodes indicates that the process in these two sites has a similar histogenesis. The absence of mesothelial surface involvement, the lack of report of mesothelial inclusions within the periaortic lymph nodes, and the known metaplastic potential of the subcoelomic mesenchyme suggest that glandular metaplasia from totipotential subcoelomic mesenchyme is the most likely histogenetic mechanism. The female hormonal milieu is essential for this process to develop since the lesions have exclusively been described in females. Chronic inflammation is a frequent associated finding and it may represent one of the metaplastic stimuli.