A Report of Two Cases of Presacral Epidermoid Cyst in Adults

Two young females in whom a pelvic mass had been found by medical check-up visited our hospital. Magnetic resonance imaging revealed 6-cm and 5-cm well-circumscribed homogeneous cysts, respectively, in the presacral region. T2 weighted images demonstrated cystic lesions with uniformly high-intensity signal. Computed tomography scans also demonstrated cystic lesions with a smooth thin wall and homogenous fluid, but not a solid structure. Therefore, we clinically diagnosed them as presacral cystic tumors, and performed complete resections by the transsacral approach with removal of coccygeal bone. In both cases, histopathological examination revealed stratified squamous epithelium but not skin appendages, so they were histopathologically diagnosed as epidermoid cysts. After surgery, anal dysfunction and tumor recurrence were not observed in either case. The presacral space is known to be the origin of various tumors that develop from embryologic structures. Among them, developmental cysts arising from any embryonic layer are classified into three groups: dermoid cyst, epidermoid cyst, and tail gut cyst, which have a risk of malignant transformation, albeit rarely. Although complete surgical resection should be carried out for these diseases, there is no clear indication of the surgical procedure or approach. Further investigations are necessary to establish surgical indications and approaches for these diseases.