Background: Tailgut cysts arise from the remnants of the tailgut during the embryonic period. Although malignant transition of tailgut cysts is very rarely observed in the clinic, this congenital condition should be carefully monitored for early diagnosis and appropriate treatment, especially when the tailgut cysts are malignant.
Case presentation: Here, we report the case of a 33-year-old man with retrorectal adenocarcinoma originating from the tailgut cysts. Magnetic resonance imaging (MRI) showed many cystic masses in the posterior rectal space, the largest of which was approximately 100 mm × 59 mm × 53 mm in size and compressed the rectum. The patient underwent surgical resection of the masses located in the retrorectal and anterior sacral spaces. Histological and immunohistological examinations confirmed adenocarcinoma transition of the tailgut cysts. The patient recovered well and was discharged 10 days after surgery.
Conclusions: We have reported a rare case of retrorectal adenocarcinoma originating from tailgut cysts. MRI, histological, and immunohistological examinations are vital for the diagnosis of tailgut cysts. Complete surgical resection of the tumor should be better performed.
Keywords: Retrorectal adenocarcinoma; Tailgut cysts.