Actinomycosis mimicking anastomotic recurrent esophageal cancer on PET-CT

We report the PET-CT appearance of actinomycosis in a 76-year-old man with a history of squamous cell carcinoma of the esophagus. The patient was initially treated with neoadjuvant chemoradiation therapy followed by esophagectomy and gastric pull-up. Hybrid PET-CT was performed 20 months after completion of treatment using a Siemens Biograph scanner 45 minutes after intravenous administration of 15 mCi of F-18 FDG. PET-CT demonstrated intense hypermetabolism to the left of the anastomosis, corresponding to a soft tissue mass on CT. The patient underwent biopsy of the mass 10 days after PET-CT examination that confirmed actinomycosis with no evidence of recurrent disease.