A case of implantation cyst difficult to differentiate from recurrence after surgery for rectal cancer

Abstract

A 52-year-old man was previously given a diagnosis of rectal cancer and underwent low anterior resection at another hospital. Sixteen months after primary surgery, serum levels of carcino-embryonic antigen (CEA) showed a slight increase. Abdominal computed tomography (CT) and magnetic resonance imaging (MRI) showed multiple cystic lesions surrounding an anastomosis site. Colonoscopy showed a smooth elevated lesion like a sub-mucosal tumor near the anastomosis. Since 18F-fluoro-deoxy-glucose positron emission tomography (FDG-PET) showed a slight accumulation of FDG at the site of cystic lesions, local recurrence was diagnosed and he was referred to our hospital. We performed Hartmann's procedure, however, histopathological examination showed no malignant findings. We therefore diagnosed the cystic lesions as implantation cyst. Implantation cyst is one of comparatively rare complications seen after gastrointestinal anastomosis that is not widely recognized. The incidence of this disorder is increasing due to the prevalence of stapled anastomosis and is also difficult to distinguish from recurrence. No previous cases which showed increased serum CEA levels and FDG accumulation by FDG-PET have been reported. We herein present this rare case of implantation cyst with a review of the literature. © 2011 The Japanese Society of Gastroenterological Surgery.