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CASE REPORT |
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| Ahead of print
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Solitary cerebellar tumefactive demyelination in a child: A radiological and histological conundrum
Akhil Mohan1, Chittur V Gopalakrishnan1, Supriya Menon2, Dilip Panikar1
1 Department of Neurosurgery, Aster Medcity, Kochi, Kerala, India
2 Department of Pathology, Aster Medcity, Kochi, Kerala, India
| Date of Submission | 23-Jun-2021 |
| Date of Decision | 10-Aug-2021 |
| Date of Acceptance | 13-Oct-2021 |
| Date of Web Publication | 30-Jan-2023 |
Correspondence Address:
Chittur V Gopalakrishnan,
Department of Neurosurgery, Aster Medcity, Kochi, Kerala
India
 Source of Support: None, Conflict of Interest: None DOI: 10.4103/jpn.JPN_139_21
 Abstract | | |
Pediatric tumefactive demyelination (TD) is a very rare pathology. There are no previous case reports of histopathologically proven solitary cerebellar TD in children. We report the case of a 7-year-old girl who presented with headache, vomiting, and imbalance. Magnetic resonance imaging (MRI) of the brain showed an irregular enhancing lesion in the left cerebellar paravermian region with perilesional edema. On a preoperative diagnosis of high-grade tumor, she underwent complete excision with an intraoperative frozen section suggestive of a glial neoplasm. Histopathology revealed a diagnosis of TD. Solitary TDs of the cerebellum in children are extremely rare. This is the first report of a histologically proven isolated cerebellar TD in a child. We discuss the diagnostic difficulty and surgical dilemma in the management of this case.
Keywords: Cerebellum, pediatric, solitary, tumefactive demyelination
| Introduction | |  |
Tumefactive demyelination (TD) is a very rare clinical condition in children; reports of this pathology have been recorded as early as 1912.[1] The prevalence of this condition was grossly underrated in the last century, and an increasing number of cases are being reported especially with the advances in magnetic resonance imaging (MRI) of the brain. These are demyelinating lesions larger than 2 cm with the variable presence of edema and ring enhancement on MRI. Nearly 60% of children with TD can subsequently develop multiple sclerosis.[2] There are very few case reports of TD in children, most of which are confined to the supratentorial region. The occurrence of pediatric TD in the cerebellum is extremely rare and to the best of our knowledge, this is the first case report of pathology-proven solitary cerebellar TD, which mimicked a high-grade cerebellar tumor on preoperative imaging.
| Case Report | | |
A 7-year-old girl presented with repeated bouts of nonprojectile vomiting and gait imbalance of 2 weeks’ duration. There was no associated headache, fever, seizures, limb weakness, sensory disturbances, or bowel and bladder symptoms. On neurological examination, the child had jerky nystagmus with left cerebellar signs. The rest of the neurological exam was essentially normal.
MRI brain with contrast revealed a 3 × 2 cm lesion in the left cerebellar paravermian region which was hypointense on T1 and hyperintense on T2 with irregular contrast enhancement [Figure 1]. There was no restriction on diffusion-weighted imaging. Spine screening did not reveal any abnormality. In view of the age of the child and MRI brain demonstrating a contrast-enhancing lesion in the left cerebellum, a provisional diagnosis of a high-grade tumor was thought and it was decided to decompress the tumor. After intravenous injection of sodium fluorescein at the time of induction of anesthesia, the child underwent a midline suboccipital craniotomy and the tumor was approached via a left paravermian corridor. Under the yellow filter, there was significant uptake of fluorescein by the tumor tissue which was soft, amenable to suction, and moderately vascular. The intraoperative frozen section of the tumor was reported as glioma. Complete tumor excision was achieved and postoperative MRI revealed complete excision of the lesion [Figure 1E]. | Figure 1: A. T1W axial MRI brain shows a hypointense lesion in the left paravermian region abutting the lateral wall of the fourth ventricle with extension into the left middle cerebellar peduncle. B. It is hyperintense on T2W axial image with perilesional edema. C and D. On intravenous gadolinium, it shows an irregular contrast enhancement. E. Postoperative MRI shows complete excision of the lesion
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Histopathology showed cerebellar tissue with sheets of foamy macrophages (CD68 +) with their cytoplasm showing myelin breakdown products. Blood vessels with dense perivascular lymphocyte cuff were seen. This picture was consistent with TD [Figure 2]. After the diagnosis of TD was confirmed, extensive workup was performed to rule out other potential diagnoses, including infections, sarcoidosis, lymphoma, and vasculitis, all of which was negative. The child had an uneventful recovery and she is on follow-up. | Figure 2: Microphotographs with hematoxylin and eosin staining (40× magnification) A. Peroperative frozen section showing sheets of moderately pleomorphic glial cells. B. Neural parenchyma with foamy macrophages. C. Perivascular lymphocyte cuffing. D. Luxol fast blue stain showing cerebellar tissue infiltrated by macrophages with ingested myelin breakdown products. E. Immunohistochemistry (IHC) of the lesion showing macrophages with CD68 positivity
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| Discussion | | |
In the pediatric age group, making a diagnosis of cerebellar TD with imaging alone is difficult due to two reasons. First, the majority of pediatric TD lesions are confined to the supratentorial brain parenchyma and secondly due to the abundance of infratentorial neoplasms in children. Solitary TDs as in our case report always call for biopsy as neoplastic etiology is a very close differential diagnosis. After a thorough literature search, only two cases of isolated cerebellar TDs in children have been reported, although it was not biopsy-proven. However, Hanumanthe et al.[3] described two children with multifocal abnormal T2 hyperintense lesions involving the brainstem, thalamus, and middle cerebellar peduncles, which were proven on biopsy as TD [Table 1]. Our case is the first documented report in a child of histopathology-proven single cerebellar TD lesion mimicking a high-grade tumor on MRI. | Table 1: Previously reported cases of pediatric infratentorial demyelination
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The pathophysiology of TD is poorly understood. Several authors have considered these lesions as the forerunner of various demyelinating pathologies such as multiple sclerosis and acute demyelinating encephalomyelopathy. TD may also be associated with other conditions such as viral infections (HIV), autoimmune diseases such as lupus erythematosus and neuromyelitis optica, and malignancies such as renal cell carcinoma. The presence of oligoclonal bands in the CSF and treatment response to immunomodulatory agents such as rituximab point to an antibody-mediated immunological mechanism. The entry of lymphocytes into the brain may be heralded by a breach in the blood–brain barrier. Typical histologic features are characterized by the presence of macrophages surrounding an area of perivascular lymphocytic infiltration (lymphocyte cuffing) consisting of B cells and T cells.[4]
The clinical features of TD depend on the location of the lesion as well as the mass effect on the surrounding brain. Mass effect due to tumefactive lesions is seen only in half of the patients.[1] MRI with contrast is the gold standard investigation which shows various forms of contrast enhancement like open or closed rings, diffuse, homogeneous, punctate, or concentric pattern. Perfusion sequences may differentiate a TD from neoplastic etiology, as these lesions have significantly lower perfusion than tumors.[5] In our case, TD was never considered in the preoperative differential diagnosis, being extremely rare and hence a routine MR perfusion was not included.
No established treatment guidelines for pediatric TD are in practice due to the rarity of this pathology among children. But in various published series, the authors recommend a course of intravenous pulsed steroids for 6 weeks and to follow the patient with a repeat MRI. If the imaging reveals a favorable clinical response, the patient may be put on close follow-up. However, if the lesion shows progression, a biopsy is warranted. If the biopsy is suggestive of TD, then the patient may be considered for plasma exchange therapy or disease-modifying agents like rituximab.[5] In our case, MRI was suggestive of an infratentorial neoplastic lesion and we did not consider TD in the differential diagnosis, being an extremely rare entity in that location. It was decided to proceed with a standard tumor excision surgery. Our patient’s intraoperative frozen section showed glial cells having nuclear atypia without lymphocyte infiltrates, which was suggestive of glial neoplasm and hence the entire lesion was excised rather than limiting to a biopsy. TDs are often misdiagnosed in intraoperative frozen smears. Neelima et al.[6] in a clinicopathological correlative study diagnosed glioma in four out of the six cases during the intraoperative frozen examination. These smears had few astrocytes with atypia along with perivascular lymphocytic infiltration, and an erroneous diagnosis of glioma was made. If a biopsy is planned for a suspected TD lesion, the target should always be the wall of the lesion, unlike in tumors where the central core of the lesion is more important.[7]
The rarity of this entity in the location described makes it difficult to formulate fixed guidelines to diagnose this lesion preoperatively. Certainly, we need to keep TD as a differential diagnosis whenever children present with acute onset neurological symptoms with MRI showing a posterior fossa lesion with irregular contrast enhancement. Perfusion MRI as part of routine preoperative imaging can help in diagnosis. Long-term outcome of pediatric TD is poorly understood. However, the adult variant is associated with a 60% chance of progression to multiple sclerosis and has a longer time of relapse in comparison with other demyelinating pathologies.
| Conclusion | | |
Solitary tumefactive demyelinating lesions in the cerebellum are extremely rare in the pediatric age group. Suspicion of tumefactive lesions in the infratentorial region on MRI mandates a biopsy, as neoplasms are the most common differential diagnosis in such cases.
Financial support and sponsorship
Nil.
Conflicts of interest
There are no conflicts of interest.
| References | | |
| 1. | Morin MP, Patenaude Y, Sinsky AB, Banwell B, Sébire G Solitary tumefactive demyelinating lesions in children. J Child Neurol 2011;26:995-9.  |
| 2. | Alroughani R, Boyko A Pediatric multiple sclerosis: A review. BMC Neurol 2018;18:27. |
| 3. | Hanumanthe SB, Francisco C, Hart J, Graves J, Waubant E Biopsy-supported tumefactive demyelination of the central nervous system in children. J Child Neurol 2016;31:1528-33. |
| 4. | Pérez CA, Patnaik A, Oommen S, Redko A, Mathis SB Tumefactive demyelinating lesions in children: A rare case of conus medullaris involvement and systematic review of the literature. J Child Neurol 2020;35:690-9. |
| 5. | Algahtani H, Shirah B, Alassiri A Tumefactive demyelinating lesions: A comprehensive review. Mult Scler Relat Disord 2017;14:72-9. |
| 6. | Neelima R, Krishnakumar K, Nair MD, Kesavadas C, Hingwala DR, Radhakrishnan VV, et al. Tumefactive demyelinating lesions: A clinicopathological correlative study. Indian J Pathol Microbiol 2012;55:496-500. [ PUBMED] [Full text] |
| 7. | Donev K, Scheithauer BW Pseudoneoplasms of the nervous system. Arch Pathol Lab Med 2010;134:404-16. |
[Figure 1], [Figure 2]
[Table 1]
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