Shunt-related brain tumor, a case report presenting a rare complication and review of literature

Abstract

Background

Congenital hydrocephalus is a well-known neurosurgical condition in the pediatric age group. Ventriculoperitoneal shunt (VPS) placement is a standard procedure with a high incidence of complications in the first year postoperatively. We present a very rare complication, with only a few reported cases in the accessible literature, in which a tumor arises in relation to a shunt catheter.

Study design

A case report.

Case presentation

We describe a case of a VPS placement in an eleven-month-old boy who, at the age of thirteen, presented with a two-month period of convulsions caused by a cortical mass related to the shunt catheter. Surgical excision of the mass revealed atypical meningioma (WHO Grade 2).

Conclusions

The tumor may have been initiated by direct irritation of the shunt catheter or just an unfortunate simultaneous event for this child. Further analysis is needed to determine which factors could have led to such a complication and to predict its occurrence in future patients. In this case, the pathologic features, duration, and unusual radiologic findings are interesting and unique.

Introduction

Congenital hydrocephalus is a well-known neurosurgical condition in the pediatric age group, with a prevalence of 6.76 per 1000 live births in Egypt [1].

While untreated hydrocephalus may result in progressive neurological deterioration and mortality, early intervention can result in the complete resolution of symptoms [2].

Ventriculoperitoneal shunt (VPS) placement is a standard neurosurgical procedure with an estimated 11–25% failure rate within the first year postoperatively [3]. This incidence declines with age, as most sources report more revisions and replacements in pediatric patients than in adults [4].

Although shunt obstruction and infection are the most common causes of shunt malfunction, other rare complications can also occur, including abdominal pseudocyst formation, bowel perforation, and over-draining, which can lead to subdural hematoma formation [5].

We present a very rare complication, with only a few reported cases in the accessible literature, in which a tumor arises in relation to a shunt catheter. The first documented case dates back to 1979 [6], in which authors described the formation of a granulomatous reaction around the shunt catheter. Other authors described the formation of a tumor (meningioma) relating to the catheter following radiotherapy [7,8,9,10].

Case presentation

We describe the case of a thirteen-year-old male child who, at eleven months, suffered from congenital hydrocephalus and underwent VPS placement with no familial history.

He presented to our clinic with two months of headaches and convulsions. The initial CT brain scan showed a well-defined, extra-axial hyperdense mass, surprisingly located close to the shunt catheter, with apparent intra-tumoral calcifications (Fig. 1).

Fig. 1

Preoperative CT scan

Convulsions were successfully controlled with medical treatment; further investigations were done, including an MRI brain with contrast, which confirmed the diagnosis of an extra-axial heterogeneously enhancing mass on GAD injection with apparent brain invasion (Figs. 2, 3).

Fig. 2

Enhanced MRI study showing proximity of tumor to shunt catheter

Fig. 3

Enhanced MRI study showing close proximity of tumor to shunt catheter

Surgical management

The patient was prepared for surgical removal of the tumor with his head fixed using Mayfield® skull clamps and a horseshoe skin flap reflected, taking care not to injure the existing VP shunt.

A mini-craniotomy was made, and the dura opened in a C-shaped fashion. Microscopic piecemeal excision of what seemed to be an extra-axial tumor, although there was no distinct cleavage plane and various consistencies with firm and calcified parts (Fig. 4).

Fig. 4

Intra-operative pictures showing tumor removal

The recovery was uneventful in the pediatric ICU, and the patient regained consciousness with no motor or sensory deficits. A postoperative CT brain scan excluded any tumor bed, extradural, or subdural hematomas (Fig. 5).

Fig. 5

Postoperative CT scan

The patient was discharged a week later with antibiotics, analgesics, and anticonvulsants prescribed as home treatments.

Histopathological studies confirmed the diagnosis of atypical meningioma (WHO Grade 2), with some worrisome patches of necrosis, mitosis, and brain invasion (Figs. 6, 7).

Fig. 6

Sections showing brain invasion, (tumor on the left, brain tissue on the right on both slides)

Fig. 7

Sections showing tumor cells with pale eosinophilic cytoplasm, plump nuclei, focally increased mitosis (left), and endothelial proliferation (right)

The immunohistochemical marker study revealed positive EMA, focally positive PR, negative GFAP, and a Ki-67 labeling index of 10%.

Discussion

This report describes a case of a thirteen-year-old male child who suffered congenital hydrocephalus at eleven months, which necessitated a ventriculoperitoneal shunt insertion.

Based on the patient records, he had a follow-up CT examination at seven years old (2017), which revealed no masses in relation to the shunt catheter (Fig. 8).

Fig. 8

CT scan 6 years ago

Two months before the current operation, he suffered from convulsions. Investigations revealed the presence of a well-defined, extra-axial mass related to the shunt catheter, which proved to be atypical meningioma (WHO Grade 2) after excision and histological studies.

The patient returned for follow-up after three months postoperatively; a new enhanced MRI study was requested and showed complete tumor excision. Anticonvulsant medications were tapered and discontinued. The existing shunt was functioning properly, so the authors chose not to replace it for the time being, with recommendations to replace it on the opposite side upon recurrence during follow-up and prior to receiving radiotherapy.

The pediatric oncology department recommended radiotherapy sessions only in case of recurrence. They also recommended sequential follow-up visits every six months for the next two years, considering the low recurrence rate associated with complete excision of the tumor and the low Ki-67 index.

Based on the literature review, only a few authors described this rare complication of a ventricular catheter-related intracranial mass, arranged chronologically in Table 1 as described by de Oliveira et al. [11].

Table 1 Intracranial lesions related to shunt catheter

Shunt manufacturers commonly utilize silicone, an inert and highly biocompatible material [15]. However, there were reports of possible immunoreactivity of silicone that could induce chronic inflammatory reaction and granuloma formation [8]. Jimenez et al. [16] described this reaction and reported 3 cases of allergic reactions to their silicon ventriculoperitoneal shunts.

It is worth noting that almost all patients who developed shunt-related meningiomas in the included studies did receive radiotherapy after resection of their primary tumors, which may contribute to oncogenesis based on a chronic inflammatory reaction around the shunt catheter and subsequent irradiation synergistically [17,18,19].

Radiation-induced neoplasia is a well-known phenomenon. However, this patient gave no history of previous radiotherapy or even frequent CT examinations. Also, his last CT scan was done 6 years ago without any gross lesions related to the shunt catheter at that time.

This study is limited by the lack of genetic analysis to assess the etiologic factors correlating meningioma formation with silicon shunt catheter presence. However, unfortunately, we do not have such research tools in our facility.

Conclusions

Ventriculoperitoneal shunts can cause many common complications. However, some authors still describe rare, unusual complications with no previous mentions in common literature, making a standardized management protocol for these rare complications unavailable.

We hypothesize that the silicone catheter has reacted as a foreign body inducing a chronic inflammatory reaction, which in turn triggered neoplastic growth, or maybe just an unfortunate simultaneous event for this child.

Further genetic and histopathologic analysis is needed to determine which factors could have led to such a complication and to predict its occurrence in future patients.

The pathologic features, duration, and unusual radiologic findings in this case are interesting and unique.