Keywords
glioblastoma - cerebellum - radiotherapy - metastatic
Introduction
Cerebellar glioblastoma is a rare tumor accounting for less than 1% of all cases of
GBM.[1] Due to its rarity in this unusual location, the pathogenesis and prognosis are not
well understood. Glioblastoma multiforme (GBM) is the most common primary brain tumor
in adults comprising ∼50% of all primary intracranial tumors. They generally occur
in the fifth and sixth decades of life.[2]
[3]
[4]
[5]
We report here a case of 36-year-old man who was diagnosed to have a recurrent left
cerebellar GBM after 5 years of gross total excision and was followed by adjuvant
radiotherapy. He was again subjected to surgery and gross total resection was achieved
following which he remains symptom free.
Case Report
A 36-year-old adult man operated somewhere 5 years ago for posterior fossa GBM and
received radiotherapy as well, presented to the casualty with history of gradual-onset
mild-to-moderate intermittent throbbing headache associated with multiple episodes
of projectile vomiting for 1 month, and instability and difficulty in walking for
15 days with Glasgow coma score of 15 ([Fig. 1]). A neurologic examination showed cerebellar signs, including cerebellar ataxia,
dysmetria, and dysdiadochokinesia. The fundoscopy revealed bilateral papilledema.
A computed tomogram and magnetic resonance imaging (MRI) of the brain revealed the
recurrence of posterior fossa solid cystic tumor with a diameter of 50 mm × 35 mm × 30 mm
([Fig. 2]). Gross total excision of the tumor and duraplasty with G patch was done using the
left retromastoid suboccipital approach. The tumor was reddish brown, firm, nonsuckable,
moderately vascular, and was adherent to the tentorium cerebelli with cystic component
having straw colored fluid. He developed wound infection and there was frank pus discharge,
culture of which revealed Methicillin resistant staphylococcus aureus (MRSA) sensitive
to colistin, and managed conservatively. Gradually, the amount of pus discharge reduced
but cerebrospinal fluid (CSF) leak was persistent. Also, serial scan revealed hydrocephalus.
He was again operated and right parietal Medium pressure ventriculoperitoneal shunt
(MPVP) shunt was done, wound was explored, and infected G patch was removed, and secondary
suturing was done. Gradually, the patient recovered over a long period of time and
there was delayed healing of the wound, might be due to radiation changes and scarring.
Fig. 1 Preoperative magnetic resonance imaging (MRI) scan shows homogenous contrast-enhancing
space-occupying lesion in the left cerebellar hemisphere with effacement of fourth
ventricle causing obstructive hydrocephalus.
Fig. 2 MRI scan with FLAIR sequence suggests recurrent homogenous contrast-enhancing SOL
having a solid and cystic component with effacement of the fourth ventricle causing
obstructive hydrocephalus and infiltrating the tentorium cerebelli.
Histopathology was suggestive of marked pleomorphism with numerous tumor giant cells
with extensive areas of coagulation necrosis with endothelial proliferation. Marked
pleomorphism with a high mitotic index was noticed. Strong immunopositivity for Glial
fibrillary acidic protein (GFAP) and p53 and negative for Isocitrate dehydrogenase
(IDH) mutant-specific antibody. Alpha thalassemia mental retardation X linked syndrome
(ATRX) was retained in the tumor cells with impression of glioblastoma grade 4 IDH
and ATRX wild-type.
Discussion
Glioblastoma multiforme (GBM) is the most common primary intracranial tumor in adults.
Although it presents at all ages, a peak incidence is seen around the sixth decade
and a second peak in the first decade.[6]
[7] The male to female ratio is 2:1.[6] The cerebellum acts as the primary site for GBM and accounts for only 0.24% to 1.00%
of all the intracranial occurences.[8] Symptoms associated with cerebellar glioblastoma are very nonspecific such as headache,
gait disturbance, vertigo, nausea, vomiting, and ataxia. And a few others such as,
dizziness, neck pain, and mental confusion can be present.[8]
[9] Our patient did have hydrocephalus as also seen in four out of nine patients in
the study by Kuroiwa et al.[8] The pathogenesis of cerebellar glioblastoma is still partially understood even after
years of research confirming its rarity. Two subsets of cerebellar GBM have been reported
by Grahovac et al.[10] They can occur de novo as in the primary type or from previous low-grade astrocytoma
as in the secondary type.[11] Primary glioblastomas affect mostly elderly patients and generally are characterized
by the loss of heterozygosity 10 q (LOH 10q) (70%), epidermal growth factor receptor
amplification (36%), and TP53 mutation at a frequency of lower than 30%,[11] whereas secondary glioblastomas are seen in younger patients and often contain TP53
mutation (65%).
The diagnosis of cerebellar GBM is always uncertain preoperatively. Computed tomography
(CT) and MRI are helpful in asserting toward the diagnosis. Cerebellar metastases,
abscess, and cerebellar infract is similar with GBM on imaging; therefore, differential
diagnosis from these diseases is difficult.[5]
[8]
[12]
Metastatic tumor is the most common differential diagnosis in adults. Solid tumors
with contrast enhancement or those with central hypodensity suggesting necrosis can
be mistaken for cerebellar GBM. Occhiogrosso et al found little peritumoral edema
in patients with cerebellar GBM, and Zito et al stated that CT was helpful in differentiating
GBM from metastasis of the cerebellum via peritumoral edema or mass effect.[6]
[13] For good tissue resolution and omitting major bone artifacts in differentiating
the lesions, MRI is a very precise diagnostic tool. Differences in vascularity and
metabolite levels in the periphery of a tumor have been helpful in differentiation
of metastases and GBMs. Metastasis may demonstrate cystic components or show hypointensity
on T2-weighted images, suggesting intratumoral hemorrhage, calcification, or mucinous
components as well as that is rare with GBM.
On CT, cerebellar GBM shows normal-appearing T2-weighted images were as those with
abscess are well-defined, thin-walled enhancing rim on contrast-enhanced T1-weighted
images.[14] Data of cerebellar GBM worldwide are very scarce and so is true for India.[9]
[15]
[16]
[17]
[18]
[19]
[20]
[21] Previously, one case report of cerebellar GBM with cerebellopontine angle extension
reported by Jindal et al and a case series of five patients from different centers
reported by Gopalakrishnan et al in 2011 from India. [Table 1] provides a review of the literature for the cerebellar GBM with an average survival
period following surgical intervention. Adams et al analyzed the SEER (Surveillance,
Epidemiology and End results) database from 1973 to 2009 and concluded that patients
with cerebellar GBM had prolonged survival as compared with supratentorial GBM. Factors
associated with prolonged survival in these patients are younger age at presentation,
radiation therapy and “Asian or Pacific Islander” race.[22] These findings were also observed in our case report as the age of first presentation
was 31 years, received radiotherapy, and he belonged to the Asian island.
Table 1
Review of cerebellar glioblastoma published in the literature
|
Author
|
No. of patients
|
Mean age
|
Location
|
Treatment
|
CT/RT
|
Median overall survival
|
|
Babu et al[15] (1975–2009)
|
247
|
59
|
Cerebellum
|
Resection(203)
Biopsy (37)
Unknown (7)
|
UK
|
7 months
|
|
Demir et al[9] (2005)
|
2
|
22.5
|
Cerebellum
|
GTR 1
STR 1
|
Yes
|
7 months
|
|
Weber et al[16] (2006)
|
45
|
50.3
|
Cerebellum
|
GTR (9)
STR (29)
Biopsy (5)
|
Yes
|
9.9 months
|
|
Jindal et al[17] (2006)
|
1
|
15
|
Cerebellum + CP angle
|
GTR
|
Yes
|
3 months
|
|
Hur et al[18] (2008)
|
1
|
69
|
Cerebellum
|
GTR
|
Yes
|
No recurrence up to 1 year
|
|
Gopalakrishnan et al[19] (2011)
|
5
|
50
|
Cerebellum
|
GTR
|
Yes
|
9 months
|
|
Hong et al[20] (2018)
|
8
|
36 ± 26
|
Cerebellum
|
GTR 4
STR 4
|
Yes
|
5.5 months (7 patient)
Still alive after 74 months (1 patient)
|
|
Kluska[21] (2020)
|
1
|
46
|
Cerebellum
|
Biopsy
|
Yes
|
Unknown
|
|
Present case (2021)
|
1
|
34
|
Cerebellum
|
GTR
|
Yes
|
72 months
|
Conclusion
Cerebellar GBM is rare and should be considered in the differential diagnosis of a
cerebellar mass lesion. MRI and contrast enhancement are two most important tools
for its characterization from its differentials. Although the median survival described
in the literature is ∼7 months, the overall survival in our case is 6 years after
recurrence.
