Pediatr Radiol (2005) 35: 815–818 DOI 10.1007/s00247-005-1456-0
Azian Abd. Aziz Lee Coleman Andrew Morokoff Wirginia Maixner
Received: 14 January 2005 Revised: 15 February 2005 Accepted: 20 February 2005 Published online: 27 April 2005 Springer-Verlag 2005
A. Abd. Aziz Æ L. Coleman (&) Department of Medical Imaging, The Royal Children’s Hospital Melbourne, Flemington Road, Parkville, Victoria 3052, Australia E-mail:
[email protected] Tel.: +61-3-93455522 Fax: +61-3-93455286 A. Morokoff Æ W. Maixner Department of Neurosurgery, The Royal Children’s Hospital Melbourne, Parkville, Australia
CASE REPORT
Diffuse choroid plexus hyperplasia: an under-diagnosed cause of hydrocephalus in children?
Abstract Hydrocephalus is a common neurological disorder in children and the result of a variety of causes. However, with the advancement of imaging modalities, particularly MRI, previously reported rarer causes of hydrocephalus in children are now being more readily appreciated. We report an 11-yearold boy with diffuse villous hyperplasia of the choroid plexus. He had a ventriculo-peritoneal (VP) shunt in-situ and a prior diagnosis from infancy of congenital aqueduct stenosis as the cause of his hydrocephalus. His current presentation was with further shunt dysfunction. CT and MRI demonstrated enlarged choroid plexuses but did not confirm
Introduction Hydrocephalus is a common neurological disorder in children due to a variety of causes [1]. With the evolution of MRI, previously reported rarer causes of hydrocephalus in children are now being more readily appreciated [1, 2]. Diffuse villous hypertrophy of the choroid plexus was originally discussed by Davis [3] in 1924 and eloquently reviewed by Britz et al. [2] in 1996, who suggested that diffuse villous hyperplasia was the correct terminology because there is diffuse enlargement of the choroid plexus fronds and increase in the number of normal-sized cells within the ventricular system, but not hypertrophy of the cells themselves. We report an interesting case of diffuse villous hyperplasia of the choroid plexus in an older child who
aqueduct stenosis. CSF overproduction was demonstrated from the externalized ventricular drain. The enlarged choroid plexuses were surgically resected and histology confirmed choroid plexus hyperplasia. Identification of choroid plexus hyperplasia is important since the neurosurgical management of hydrocephalus is not VP shunt insertion, but resection of the hyperplastic choroid plexus.
Keywords Hydrocephalus Æ Choroid plexus hyperplasia Æ MRI Æ Child
had a ventriculo-peritoneal (VP) shunt in situ and a prior diagnosis from infancy of congenital aqueduct stenosis as the cause of the hydrocephalus.
Case report An 11-year-old boy with developmental delay, autism and epilepsy was referred with the suspicion of VP shunt dysfunction. His clinical condition had been deteriorating over the past 2–3 weeks; he was less responsive than usual and had been vomiting for a few days prior to this admission. His mother was also concerned that his abdomen had become increasingly distended over the past few years. He had a past history of VP shunt insertion for congenital aqueduct stenosis at the age of 2 months at another hospital. The
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VP shunt had been revised three times since, the last at 5 years of age. His epilepsy was treated with long-term anticonvulsants. On examination he was drowsy, irritable and uncooperative. Otherwise, no neurological deficit was elicited. Biochemical investigations were unremarkable. Imaging performed on arrival demonstrated shunt tubing disruption over the chest. Contrast-enhanced CT (Fig. 1) confirmed markedly dilated ventricles and prominent, bilateral, enhancing lateral-ventricular choroid plexuses. At this time, no prior imaging was available for review. He was immediately taken to surgery. Upon removing the fractured peritoneal catheter, more than 1 l of clear fluid was expressed from the peritoneum under some pressure. The shunt was externalized as there was concern that the ascitic fluid represented a low-grade peritonitis. In the recovery room, 160 ml of CSF was drained over 90 min from the externalized ventricular drain. Later that same evening, gadolinium-enhanced MRI of the brain was performed (Fig. 1). It clearly demonstrated the enlarged, frond-like, moderately enhancing lateral ventricular choroid plexuses. Lateral ventriculomegaly remained even though the VP shunt had been externalized. There was no tectal plate tumour evident, given the prior diagnosis of aqueductal stenosis. No flow void was demonstrated in the aqueduct of Sylvius but he had an externalized VP shunt present at the time of this MRI study. No prior MRI of the brain had ever been performed on this child. Over the next 48 h post externalization of the VP shunt, he continued to drain
Fig. 1 Enlarged choroid plexus. a Contrast-enhanced CT at the time of the most recent admission shows dilated lateral ventricles with enlarged and enhancing choroid plexuses. Axial (b) and coronal (c) gadolinium-enhanced MRI on the same day clearly demonstrate the enlarged (hyperplastic) choroid plexuses in the dilated lateral ventricles
excessive amounts of CSF (100 ml/h). At this point, the presumptive diagnosis of enlarged hyperplastic and nonpapillomatous choroid plexuses as the cause for the CSF overproduction was made. Given this diagnosis, he underwent elective excision of the right lateral ventricular choroid plexus via a small parieto-occipital craniotomy. Post-operatively he did well, with no complications and CSF drainage reduced to 40 ml/h. One week later, the hyperplastic left lateral ventricular choroid plexus was removed. Following this procedure, CSF drainage reduced to normal levels—10– 15 ml/h (normal CSF production is 0.20–0.35 ml/min; [4]). Microscopic examination (Fig. 2) of the tissue removed at both operations demonstrated prominent papillary fronds lined by a single layer of low cuboidal epithelial cells resembling normal choroid plexus. There was increased vascularity and psammoma bodies were seen. The whole structure assumed an excessive frond-like growth. There was no evidence of malignancy. Findings were compatible with choroid plexus hyperplasia. Subsequently, he underwent a third ventriculostomy that eliminated his requirement for a VP shunt and he was discharged home. Following his discharge we were able to retrieve all his previous CT brain imaging (Fig. 3). The original non-contrast CT scan of the brain was performed when he was 2 weeks old and a subsequent scan was obtained because of suspected shunt dysfunction 1 year later. Both studies showed dilated lateral ventricles and, in retrospect, demonstrated bulky lateral ventricular choroid plexuses.
Discussion Diffuse villous hyperplasia of the choroid plexus causing overproduction of CSF and shunt-resistant hydroceph-
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Fig. 2 Numerous frond-like structures from a fibrovascular stalk (H & E, ·10). Inset Cobble-stone epithelial lining cells resembling normal choroid plexus (H & E, ·400)
alus is a rare entity and has been difficult to diagnose prior to the advent of MRI [5, 6]. There are scattered case reports in the paediatric neurosurgical literature of children presenting from 2 weeks to 7 years of age with hydrocephalus, treated with VP shunting, but the diagnosis of villous hyperplasia not being appreciated initially as the cause of the hydrocephalus [2, 5–9]. It is only after ‘shunt failure’ or development of massive ascites associated with correctly interpreted MRI that the diagnosis has been made. In the past, terms such as ‘villous hypertrophy’, ‘villous hyperplasia’ and ‘bilateral choroid papillomas’ have
Fig. 3 The earlier CT scans. a The initial non-enhanced CT at 2 weeks of age shows dilated lateral ventricles and, in retrospect, rather prominent choroid plexuses. b Follow-up non-enhanced CT brain following insertion of a VP shunt 19 months later again reveals dilated lateral ventricles. The choroid plexuses appear to abut the medial walls of the lateral ventricles, making it difficult to assess whether they are enlarged
been used interchangeably [6]. However, these are distinct pathological entities [2, 6, 10] and, as discussed by Britz et al. [2], villous hyperplasia rather than villous hypertrophy is the more appropriate term for non-papillomatous over-secreting choroid plexus. Gadolinium-enhanced MRI should be able to differentiate the diffusely enlarged, but not avidly enhancing, choroid plexus from the extremely enhancing, nodular, lobulated, markedly enlarged papillomatous choroid plexus [1, 10]. Difficulty could arise, however, in the child with mild-to-moderate hydrocephalus with enhancing ‘minimally bulky’ choroid plexus. It is in this situation the radiologist must be aware and consider villous hyperplasia as a possible cause for the hydrocephalus, as neurosurgical management of this cause of hydrocephalus is not a VP shunt, but either unilateral or bilateral resection of the lateral ventricular choroid plexus [5, 8]. Our case demonstrates many of the issues discussed above. The initial CT of our child, performed at 2 weeks of age, showed dilated ventricles and was interpreted as showing aqueductal stenosis. The lateral ventricular choroid plexuses were thought to be within normal limits. However, with the luxury of hindsight and reviewing all the imaging 10 years on, we believe that the original CT scan showed bulky choroid plexuses for the patient’s age. Associated aqueduct stenosis has never been confirmed or refuted even at this current presentation. His MRI has been performed with either an externalised VP shunt or following third ventriculostomy and bilateral choroid plexus resection. CSF flow through the aqueduct could not be adequately assessed. However, there was no demonstrable tectal plate lesion.
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Previous reports have mentioned the difficulties in diagnosing choroid plexus hyperplasia and differentiating it from choroid plexus papilloma, both of which cause hydrocephalus from excessive production of CSF [2, 5, 7, 8]. CT and particularly contrast-enhanced MRI have been reported to be useful in the diagnosis of choroid plexus hyperplasia [5, 8]. Although CT often shows the dilated lateral ventricles, the enlarged choroid plexus is seldom clearly identified, especially on nonenhanced CT [2]. In our case, the enlarged choroid plexuses were identified on the enhanced CT and were clearly demonstrated on the contrast-enhanced MRI as enlarged, enhancing frond-like structures. The main feature that distinguished our case of choroid plexus hyperplasia from a papilloma was the only moderate enhancement of both choroid plexuses following injec-
tion of gadolinium. Papillomas enhance very avidly [1, 10]. This is an important distinguishing feature that has not been highlighted in previous reports. Furthermore, Britz et al. [2] described papilloma as a discrete mass while hyperplasia is defined as diffuse enlargement of the entire choroid plexus throughout the length of the choroidal fissure, a feature that our case demonstrated. Although choroid plexus hyperplasia is a rare cause of hydrocephalus in children, it is important that careful assessment of contrast-enhanced CT or MRI is undertaken, particularly when there is no clear cause for the hydrocephalus. Acknowledgements We thank Dr. Yuen Chan and Dr. Beena Kumar from the Department of Pathology, The Royal Children’s Hospital, for providing the histological illustrations.
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8. Hirano H, Hirahara K, Asakura T, et al (1994) Hydrocephalus due to villous hypertrophy of the choroid plexus in the lateral ventricles. Case report. J Neurosurg 80:321–323 9. Welch K, Strand R, Bresnan M, et al (1983) Congenital hydrocephalus due to villous hypertrophy of the telencephalic choroid plexus. Case report. J Neurosurg 59:172–175 10. Fujimura M, Onuma T, Kameyama M, et al (2004) Hydrocephalus due to cerebrospinal fluid overproduction of bilateral choroid plexus papillomas. Childs Nerv Syst 20:485–488
