Unusual cause of breast lump: a CSF pseudocyst

A ventriculoperitoneal (VP) shunt is a fairly common and useful procedure to reduce intracranial pressure in patients with hydrocephalus. Complications associated with VP shunts are usually related to either shunt obstruction or infection. A pseudocyst formation owing to leakage of CSF into the breast tissue as a complication of VP shunting is a rare entity, with few cases in the literature. Nonetheless, it is an important cause of cystic breast lump and should be kept in mind in a patient with an indwelling VP shunt. We describe the case of a 16-year-old girl patient with an indwelling VP shunt who presented with a gradually increasing breast lump, and was diagnosed to have a CSF pseudocyst based on characteristic imaging findings.