Serous tumor of low malignant potential arising in inguinal endosalpingiosis: Report of a case

A 46-year-old woman presented with a right inguinal mass. Imaging studies revealed no abnormalities of the pelvis (including the ovaries) or abdomen. The inguinal mass was composed predominantly of variably sized cysts lined by flat to low cuboidal cells resembling mesothelial cells and ciliated columnar tubal-type cells with a focal transition between the two cell types. Papillae, detached cell clusters with mild cytologic atypia, and psammoma bodies were also found, warranting a diagnosis of a serous borderline tumor. This appears to be the first report of a serous borderline tumor arising in inguinal endosalpingiosis and not associated with an ovarian serous tumor.