An immunosuppressed, neutropenic patient developed symptoms and signs of acute cholecystitis. Gallbladder ultrasound was consistent with acute cholecystitis. Technetium-99m-diisopropyl iminodiacetic acid (DISIDA) scan showed a rim sign, but with normal gallbladder visualization. On restudy 72 hr later when the patient's WBC count was recovering, the 99mTc-DISIDA scan again showed a persistent rim sign, but now there was no gallbladder visualization at 1 hr, a pattern strongly predictive for acute complicated cholecystitis. Biliary drainage was performed by percutaneous cholecystotomy with clinical improvement. Semielective cholecystectomy performed 8 wk later confirmed both acute and chronic cholecystitis. We describe the rim sign and its variants, mechanisms of causation, prognostic importance and correlate our report with a review of the literature.