A carcinoembryonic antigen-secreting adenocarcinoma arising within a retrorectal tailgut cyst: Clinicopathological considerations

Retrorectal tailgut cysts (TGC) develop from postanal fetal gut remnants. T hey have specific radiological and histopathological features that distingu ish them from dermoid cysts, enteric duplication cysts, and teratomas. We r eport a patient with a carcinoembryonic antigen-producing adenocarcinoma ar ising within a TGC who underwent resection through a combined anterior lapa rotomy/posterior pelvic approach. Despite complete resection and delayed bu t complete functional recovery, diffusely metastatic disease was encountere d 6 months after resection. Diagnostic, therapeutic, histopathological, and oncological implications of this illustrative case are discussed. It seems possible to use carcinoembryonic antigen measurements for treatment planni ng and for assessing treatment response for this rare disease. The describe d outcome also suggests that TGC can develop malignant degeneration and sho uld be resected at the time of diagnosis. (C) 2000 by Am. Coll. of Gastroen terology.