====== Choroid plexus hyperplasia ====== Choroid plexus [[hyperplasia]] (CPH), also known as villous hypertrophy of the [[choroid plexus]], is a rare benign condition that is characterized by bilateral enlargement of the entire choroid plexus in [[lateral ventricle]]s without any discrete masses. This can result in overproduction of [[CSF]] and [[communicating hydrocephalus]]. ===== Pathophysiology ===== Despite the current knowledge about hydrocephalus, we remain without a complete understanding of the pathophysiology of this condition. [[glymphatic system]] (GS) could be more important than the conventional concept of reabsorption of CSF in the arachnoid villi, therefore GS could be a new key point, which will guide future investigations ((Paez-Nova M, Andaur K, Campos G, Garcia-Ballestas E, Moscote-Salazar LR, Koller O, Valenzuela S. Bilateral hyperplasia of choroid plexus with severe CSF production: a case report and review of the glymphatic system. Childs Nerv Syst. 2021 Nov;37(11):3521-3529. doi: 10.1007/s00381-021-05325-2. Epub 2021 Aug 19. PMID: 34410450.)). ===== Pathology ===== Histology shows an increased number of normal-sized cells. ===== Radiographic features ===== ==== MRI ==== This is best diagnosed by [[MRI]] which demonstrates a diffuse enlargement and homogeneous enhancement of choroid plexuses in a patient with communicating hydrocephalus ((https://radiopaedia.org/articles/choroid-plexus-hyperplasia)). ===== Treatment ===== It is a rare condition that may necessitate unusual treatment paradigms. Although some authors recommend choroid plexus excision or coagulation, ventriculoatrial shunt insertion is a simple and effective treatment modality in cases of diffuse villous hyperplasia of the choroid plexus ((Iplikcioglu AC, Bek S, Gökduman CA, Bikmaz K, Cosar M. Diffuse villous hyperplasia of choroid plexus. Acta Neurochir (Wien). 2006 Jun;148(6):691-4; discussion 694. doi: 10.1007/s00701-006-0753-1. Epub 2006 Mar 8. PMID: 16523225.)). It can be seen in [[trisomy 9p]] where coexisting [[congenital heart disease]] additionally may complicate the therapeutic approach ((Henningsen MB, Gulisano HA, Bjarkam CR. [[Congenital hydrocephalus]] in a [[trisomy 9p]] gained [[child]]: a [[case report]]. J Med Case Rep. 2022 May 27;16(1):206. doi: 10.1186/s13256-022-03424-5. PMID: 35619116.)). ===== Case reports ===== At 20 months of age, a [[Caucasian]] girl with [[trisomy]] 9 and a [[family history]] of an older brother and [[twin]] sister having the same syndrome displayed signs of [[congenital hydrocephalus]] due to increasing [[head circumference]]. [[Magnetic resonance imaging]] revealed enlarged [[lateral ventricle]]s and a prominent [[choroid plexus]] and the girl was treated with a [[ventriculoperitoneal shunt]], which 2 days later had to be replaced with a [[ventriculoatrial shunt]] as [[cerebrospinal fluid production]] greatly exceeded the ability of the patient's abdominal absorptive capability. At 16 years of age, the patient was diagnosed with [[cardiomyopathy]] and diminished ejection fraction. Some months later, she was admitted to the neurosurgical ward showing signs of [[shunt dysfunction]] due to a [[colloid cyst]] in the [[third ventricle]]. Cystic drainage through endoscopic puncture only helped temporarily. Revision of the [[shunt]] [[system]] showed occlusion of the [[ventricular drainage]], and [[replacement]] was merely temporary alleviating. [[Intracranial pressure]] was significantly increased at around 30 mmHg, prompting externalization of the drain, and measurements revealed high [[cerebrospinal fluid production]] of 60-100 ml liquor per hour. Thus, endoscopic [[choroid plexus coagulation]] was performed bilaterally leading to an immediate decrease of daily [[cerebrospinal fluid]] formation to 20-30 ml liquor per hour, and these values were stabilized by pharmaceutical treatment with [[acetazolamide]] 100 mg/kg/day and [[furosemide]] 1 mg/kg/day. Subsequently, a [[ventriculoperitoneal shunt]] was placed. Follow-up after 1 and 2 months displayed no signs of [[hydrocephalus]] or [[ascites]]. High [[cerebrospinal fluid volume]] load and coexisting [[heart disease]] in children with [[trisomy 9p]] may call for endoscopic [[choroid plexus coagulation]] and pharmacological therapy to diminish the daily [[cerebrospinal fluid production]] to volumes that allow proper [[ventriculoperitoneal shunt]]ing ((Henningsen MB, Gulisano HA, Bjarkam CR. [[Congenital hydrocephalus]] in a [[trisomy 9p]] gained [[child]]: a [[case report]]. J Med Case Rep. 2022 May 27;16(1):206. doi: 10.1186/s13256-022-03424-5. PMID: 35619116.)). ---- A 1-year-old patient was diagnosed with communicating hydrocephalus; ventricle peritoneal shunt (VPS) is installed and ascites developed. VPS is exposed, yielding volumes of 1000-1200ml/day CSF per day. MRI is performed showing generalized choroidal plexus hyperplasia. Bilateral endoscopic coagulation of thechoroid plexus was performed in 2 stages (CPC) however the high rate of CSF production persisted, needing a bilateral plexectomy through septostomy, which finally decreased the CSF outflow. New knowledge about CSF physiology will help to propose better treatment depending on the cause of the hydrocephalus. The GS is becoming an additional reason to better study and develop new therapies focused on the modulation of alternative CSF reabsorption. ((Paez-Nova M, Andaur K, Campos G, Garcia-Ballestas E, Moscote-Salazar LR, Koller O, Valenzuela S. Bilateral hyperplasia of choroid plexus with severe CSF production: a case report and review of the glymphatic system. Childs Nerv Syst. 2021 Nov;37(11):3521-3529. doi: 10.1007/s00381-021-05325-2. Epub 2021 Aug 19. PMID: 34410450.)). ---- In these patients, intractable ascites can occur after a ventriculoperitoneal (VP) shunting operation. However, shunt-related hydrocele is a rare complication of VP shunting. Previous reports have indicated catheter-tip migration to the scrotum as a cause of hydrocele. Here, we present the first documented case of choroid plexus hyperplasia that led to intractable ascites after shunting and a resulting hydrocele without catheter-tip migration into the scrotum ((Hori YS, Nagakita K, Ebisudani Y, Aoi M, Shinno Y, Fukuhara T. Choroid Plexus Hyperplasia with Intractable Ascites and a Resulting Communicating Hydrocele following Shunt Operation for Hydrocephalus. Pediatr Neurosurg. 2018;53(6):407-412. doi: 10.1159/000492333. Epub 2018 Aug 29. PMID: 30157489.)).