A CSF pseudocyst.

A 51-year-old female with prior history of ventriculoperitoneal shunt presented with worsening abdominal distension. Her abdomen was diffusely tender and firm with a slight fluid wave. CT imaging with IV contrast was notable for a large cystic lesion in the abdominal cavity with the differential of CSF pseudocyst versus ovarian mass. She underwent paracentesis of the cyst with interventional radiology and required a revision of her ventriculoperitoneal shunt. CSF pseudocysts are a rare complication of ventriculoperitoneal shunts, however, are an important consideration in patients presenting with abdominal complaints and require specialized intervention and assessment.