Paediatric Epstein–Barr virus-associated intracranial smooth muscle tumours

Dear Sir, Epstein–Barr virus (EBV)-associated smooth muscle tumours (SMTs) are uncommon entities typically found in immunocompromised patients. Intracranial occurrence in children is rare. We report a case in a 3-year-old, post-liver transplant female patient who was receiving tacrolimus and mycophenolic acid as immunosuppressants. The patient presented with acute respiratory distress and persistent non-distractable left-sided jerking of the arms and legs. A right main bronchus (RMB) and a large frontoparietal interhemispheric mass [Figure 1] were discovered. She underwent resection of the RMB mass, followed by the intracranial mass via a bicoronal incision. A moderately vascular solid-cystic lesion with relatively good brain–tumour interface was found intraoperatively. A small remnant adjacent to the superior sagittal sinus was left due to persistent venous oozing. Postoperative scan showed a small remnant along the right perirolandic region. Histology demonstrated strongly positive smooth muscle actin and EBV-encoded RNA in situ hybridisation stains, compatible with EBV-associated SMT. Postoperatively, she was neurologically intact, and her seizures resolved. She was started on sirolimus, a mammalian target of rapamycin (mTOR) inhibitor reported to be effective in other parts of the body; no chemotherapy or radiotherapy was given. Follow-up at 14 months showed smaller residual and no new lesions.Figure 1: Imaging of the intracranial lesion. (a & b) Axial MR images demonstrate an extra-axial, solid-cystic, multilobulated lesion in the bilateral parasagittal frontoparietal regions crossing the midline, with multiple blood-fluid levels, areas of necrosis and rim enhancement. (c) CT venogram confirms attenuated flow in the middle third of the superior sagittal sinus, either compressed or invaded.The literature on these conditions is sparse, with nine cases reported to date [Table 1].[1,2,3,4,5] There was a female preponderance (F:M = 7:2), most cases occurred in the first decade and all were immunocompromised. Treatment included surgery, radiotherapy, systemic chemotherapy, adjustment of human immunodeficiency virus therapy or reduction of immunosuppressants. Surgery was the most frequent modality; none of the operated patients received adjuvant therapy. Reported outcomes were favourable, with minimal progression and/or no recurrence at follow-up.Table 1: Summary of paediatric intracranial Epstein–Barr virus-associated smooth muscle tumours.There is no treatment consensus for these lesions due to their rarity. Surgery appears to be the favoured option with reasonably good results to date. Indications for surgery include histological diagnosis and relief of mass effect. Aggressive chemotherapy is avoided, as it exposes the already immunocompromised paediatric patients to greater risk of severe infections, leading to poorer outcomes. Another paediatric-specific consideration is the limited role of radiotherapy in disease control, given its known adverse side effects and latent cognitive impairments. While reduction of immunosuppressive treatment for post-transplantation patients may be trialled, the risk of organ failure from graft versus host disease limits its effectiveness as a major therapeutic method.[2,3,4] mTOR inhibitors have gained increasing attention due to their effectiveness in EBV-associated SMTs in other regions of the body.[5] Our patient received adjuvant sirolimus, and its robust outcome holds promise for similar patients in future. Although intracranial EBV-associated SMTs are rare, they should be considered in the differential diagnosis of all immunocompromised paediatric patients. Patient care should be discussed at institutional multidisciplinary meetings for optimal individualised management. Where feasible, surgical resection should be considered as the first-line intervention for intracranial lesions, with reduction of immunosuppression and mTOR inhibitors, where appropriate, as important adjunct treatment strategies. Chemotherapy and radiotherapy are less desirable options in the paediatric population. The importance of long-term follow-up and surveillance imaging cannot be over-emphasised, given the risk of recurrence. Financial support and sponsorship Nil. Conflicts of interest There are no conflicts of interest.