Infected adrenal pseudocyst mimicking a duodenal duplication cyst

A nine year-old boy with a complex medical history, including Phelan-McDermid syndrome, autism spectrum disorder, and focal epilepsy was admitted from Infectious Disease (ID) clinic for persistent fever for over three weeks. Laboratory studies were significant for leukocytosis, elevated inflammatory markers, transaminitis, and anemia. He was initially thought to have an infected duodenal duplication cyst with secondary parapneumonic involvement on imaging. Exploration revealed a densely inflamed suprarenal cyst with a communication to the duodenum. Pathology revealed an infected and hemorrhagic adrenal pseudocyst. We speculate that he had a relatively old or subacute hemorrhagic adrenal pseudo cyst that subsequently became infected and perforated into the duodenum and sub-diaphragmatic space.