CSF pseudocyst: an unusual cause of back pain

Abstract

DESCRIPTIONA 27-year-old woman presented with a 10-month history of right-upper back pain that radiated anterolaterally along the right chest wall and was aggravated by coughing and deep inspiration. She had surgical resection of a low-grade cerebellar astrocytoma 21 years previously. Since that time, she had a ventriculoperitoneal (VP) shunt.MRI of the cervicothoracic spinal cord failed to demonstrate any spinal abnormality to account for pain. However, there was a 15×8 cm cystic collection in the right-upper abdominal quadrant ( figure 1A, B; black star). CT of the abdomen was performed for further evaluation. Scout (figure 2A) and axial CT (figure 2B) images revealed the distal tip of the VP shunt coiled in the right subphrenic space) (arrows) and surrounded by a large simple cystic collection compressing the liver. A large amount of clear, serous fluid was drained percutaneously using ultrasound guidance. Laboratory analysis of the fluid was consistent with cerebrospinal fluid (CSF). The shunt was repositioned and her symptoms subsequently resolved. CSFoma is a rare complication of VP shunts particularly in adults.1 A thin fibrous capsule without