Adult medulloblastoma and the "dural-tail" sign: rare mimic of a posterior petrous meningioma

Medulloblastoma at the cerebello-pontine angle resembling vestibular schwannoma: A case report and review of the literature

Cerebello-pontine angle (CPA) tumors account for only less than 10 % of intracranial tumors, it usually affects children at a young age with the midline being the most favorable location. Our adult patient demonstrated a very unusual site for medulloblastoma at the CPA. Less than 50 cases all around the world have been reported in the English literature for Medulloblastoma to be located at the CPA, and most of them in pediatric age group.

We report a 43 year old female patient who presented to our neurosurgical ward in Jerusalem with a 4 months history of progressive decreased hearing at the left side, accompanied with tinnitus, dizziness, and imbalance on walking. Medulloblastoma at the CPA was one of the differential diagnosis and was confirmed at our histopathology unit after gross total resection of the tumor, the surgery followed by radiotherapy and the patient was well after 9 months after procedure.

MB-CPA is a relatively rare tumor, and the early diagnosis make a difference in the management, prognosis, and outcomes, so it should be considered as a differential diagnosis of a lesion of the CPA.

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Medulloblastoma at the Cerebello-Pontine Angle (CPA MB) is a rare aggressive tumor that can mostly occur in children and extremely rare in adults.

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Aggressive surgical resection is the first line in management.

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Post-operative radiation therapy and/or chemotherapy play a role in reducing recurrence.

Low apparent diffusion coefficient in an extracranial brain tumor: a case report

Background

Medulloblastoma is well known as the most common malignant brain tumor identified in children, frequently found at an intra-axial location in the posterior cranial fossa. Extra-axial medulloblastoma is uncommon and often misdiagnosed. We believe that a thorough understanding of atypical medulloblastoma cases is important in daily practice.

Case presentation

We present the unique case of a 39-year-old woman of Asian descent who suffered from headaches and right-sided hearing impairment. A right extra-axial medulloblastoma with an extremely low apparent diffusion coefficient of 0.404 × 10⁻³ mm²/second was detected on magnetic resonance imaging. The initial diagnosis suggested schwannoma or hemangioblastoma. However, the postoperative histopathologic findings indicated medulloblastoma (World Health Organization grade IV). Pre- and postoperative magnetic resonance imaging revealed no drop metastasis, but adjuvant radiation therapy was still required as a standard treatment therapy

Conclusions

Extra-axial medulloblastoma is an uncommon tumor that is often mistaken for other cerebellopontine angle neoplasms. We describe a rare example of extra-axial medulloblastoma, characterized by a low apparent diffusion coefficient. When evaluating an atypical cerebellopontine angle neoplasm, the apparent diffusion coefficient should be considered a relevant indicator.

Extra-axial adult cerebellopontine angle medulloblastoma: Revisiting a rare entity

A purely extra-axial position of medulloblastoma in adults at cerebellopontine (CP) angle is extremely rare. To the best of our knowledge, only ten cases have been reported till date. The authors report a case of extra-axial medulloblastoma in a 30-year-old female located at right CP angle. It was surgically treated with a provisional diagnosis of meningioma. Histopathological diagnosis of desmoplastic/nodular medulloblastoma was made with the routine hematoxylin eosin (HE) stain and immunohistochemical markers. This case report highlights the fact that, although extremely rare, the possibility of an extra-axial CP angle mass being a medulloblastoma still needs to be considered in the differential diagnoses, even in adults.

Extra-axial Desmoplastic Medulloblastoma in Adult Cerebellopontine Angle: Case Report and Noninvasive Molecular Subgrouping Utilizing Magnetic Resonance Imaging-Based Radiomics Nomogram

Cerebellopontine angle (CPA) is an atypical site for adult medulloblastoma (MB) with only 12 cases reported in pure extra-axial location. None was predicted on preoperative imaging while the most common misdiagnosis was petrous meningioma. We add the 13^th case to this list, attempting to reiterate the radiological features for preoperative prediction of this rare pathology on conventional magnetic resonance imaging (MRI). Molecular subtyping also is not yet reported for adult extra-axial CPA MB. We propose the routine use of MRI-based nomograms, in atypical CPA extra-axial masses, for noninvasive prediction of molecular subgroup, especially in resource-limited setups that lack the facility of genetic profiling.

Extra-axial tentorial medulloblastoma: a rare presentation of a common posterior fossa tumour

Medulloblastoma is a common paediatric posterior fossa tumour typically presenting as midline intra-axial mass involving the cerebellar vermis and/or roof of fourth ventricle with typical radiological features. These can be extra-axial in extremely rare instances with less than 50 cases reported so far in literature. We present a case of 18-year-old boy presenting with ataxia and headache. MRI showed dural mass (involving the left tentorium cerebellum) with typical imaging features of extra-axial lesion. The patient underwent near total excision of the tumour. Histopathology along with immunohistochemistry revealed the mass to be medulloblastoma. We present this case to highlight rarity of this location for medulloblastoma and the importance of considering this in the differential diagnosis of atypical posterior fossa extra-axial lesions. This can help in performing other relevant preoperative workup similar on the lines of medulloblastoma and planning of relevant management.

Posterior fossa extra-axial variations of medulloblastoma: a pictorial review as a primer for radiologists

Manifestations of an atypical variant of medulloblastoma of the posterior fossa in extra-axial locations have been reported, and key questions concerning its interpretation have been raised previously. This review illustrated the clinico-radiological and histopathological features of the posterior fossa extra-axial medulloblastoma and described possible management strategies. We thoroughly reviewed all atypical anatomical locations of medulloblastoma reported within the posterior fossa and extra-axial spaces. The main characteristics of diagnostic imaging and histopathological results, primarily the distinctive radiopathological characteristics, were summarized to distinguish between intra- and extra-axial medulloblastoma, or pathologies mimicking this tumor. Most cases of posterior fossa extra-axial medulloblastoma have been reported in the cerebellopontine angle, followed by the tentorial and lateral cerebellar locations. The dural tail sign, which is commonly observed in meningioma, is rarely seen in intra- or extra-axial medulloblastoma and might be associated with other benign or malignant lesions. In addition to magnetic resonance imaging, the proposed new imaging techniques, including advances in modern neuroimaging modalities, were discussed, as potentially efficient modalities for characterizing extra-axial medulloblastoma. Radionuclide imaging and magnetic resonance perfusion imaging are practical alternatives to limit the number of differential diagnoses. We believe that medulloblastoma cases are likely under-reported because of publication bias and frequent tumors in unusual locations. Addressing these issues would help establish a more accurate understanding of this entity.

Historadiological Correlation of Cerebellopontine Angle Tumors: Series of 122 Cases

Cerebellopontine angle (CPA) tumours, are diverse pathologically with regard to the site of tumour origin and displacement of the neurovascular structures. In general CPA tumours are divided into acoustic and non-acoustic tumours. The aim of the present study was to see the spectrum of lesions at cerebellopontine angle and their historadiological correlation. A retrospective analysis of 122 cases of CPA tumors diagnosed in the Department of Pathology, IHBAS was done from January 2004 to August 2019. There were 56 males and 66 females in the age group of 8-68 years. Clinical history ranged from 10 days to 5 years. Clinical symptoms included hearing deficit, visual loss, facial nerve dysfunction, nausea, vomiting, headache, seizures, unsteadiness and disequilibrium. Historadiological correlation was found in 112 cases (91%).In our series of CPA tumors, nonacoustic tumors were more frequent than in previous studies. We found that presence of intrameatal fraction is not exclusive only for schwannomas. There can be a rare occurrence of medullobastoma/small round cell tumor in CP angle. The final pathological verification can at times give unexpected results. Immunohistochemistry did not have a significant role in diagnosis of cerebellopontine angle tumors.

Medulloblastomas in cerebellopontine angle: Epidemiology, clinical manifestations, imaging features, molecular analysis and surgical outcome

Cerebellopontine angle (CPA) medulloblastoma is rare and short of system description. We attempted to clarify its epidemiology, clinical manifestations, imaging features, pathological and molecular types, and surgical outcomes. 8 patients from 7 to 52 years old were enrolled in this retrospective study, with mean age 21.6 ± 16.4 years. The most frequent symptoms were raised intracranial pressure (100%), followed by cerebellar signs (50%), decreased hearing (50%), facial paralysis (50%), abducent paralysis (50%), and facial paresthesia (37.5%). MRI demonstrated a solid CPA lesion with heterogeneously weak or significant enhancement after gadolinium administration, accompanied with peritumoral oedema (75%), cystic change (62.5%) and dural tail sign (50%), while CT showed petrous bone and internal auditory canal intact. All cases received tumor excision, with 6 (75%) cases undergoing gross total resection, and the remaining (25%) getting partial excision. Pathological examination confirmed 5 (62.5%) classic, 2 (25%) desmoplastic, and 1 (12.5%) anaplastic. Further molecular analysis identified 5 (62.5%) WNT and 3 (37.5%) SHH. Immediately after the primary surgery, 7 (87.5%) cases gained improvement of the symptoms and signs and 1 (12.5%) kept the preoperative status stable. Follow up was available ranged from 5 to 34 months, during that period 5 cases kept symptom free and 3 cases recurred/progressed. In conclusion, CPA medulloblastoma is rare and lacking of special clinical manifestations and radiological features, and should be considered in the differential diagnosis of CPA lesions. In this series the most frequent pathological and molecular type is classic and WNT. Microsurgery excision is effective to prevent progressive decline of neurological status.

A Rare Extra-Axial Midline Tentorial Adult Medulloblastoma with Dural-Tail Sign Mimicking a Meningioma

Medulloblastomas are categorized as the World Health Organization Grade IV neoplasms. Only 33 cases have been reported of extra-axial, mostly in the cerebellar pontine angle and lateral cerebellar hemisphere, medulloblastomas in the current literature. Our study showcases the first case of an extremely rare presentation of an extra-axial midline tentorial adult medulloblastoma with the dural-tail sign mimicking a meningioma. To achieve the best possible outcome, a high index of suspicion for medulloblastoma is critical especially in young patient with an atypical posterior fossa mass as treatment regimens drastically different between a medulloblastoma and a meningioma.

Prevalence and Surgical Implications of Dural Enhancement at the Porus Acusticus in Vestibular Schwannomas

OBJECTIVE

Demonstrate the association of radiographic dural enhancement with increased tumor adherence at the porus acusticus, which may influence completeness of resection and facial nerve outcome.

STUDY DESIGN

Case series with chart review.

SETTING

Academic referral center.

SUBJECTS AND METHODS

A total of 205 consecutive patients with histopathologically confirmed vestibular schwannoma (VS) were evaluated. Patients with tumors exhibiting dural enhancement on postgadolinium T1-weighted magnetic resonance imaging were identified and compared with matched controls. Completeness of resection, intraoperative details, and facial nerve outcomes were analyzed.

RESULTS

Excluding strictly intracanalicular tumors (n = 32, 16%) and those with NF2 (n = 10, 4.9%), the presence of dural enhancement was radiographically confirmed in 16 (9.8%) cases. Paired analysis did not reveal significant baseline differences between cases and controls. Subtotal resection was performed in 5 (31%) of the 16 patients with tumors exhibiting dural enhancement, in contrast to 1 (3%) of the matched controls (P = .01). Four (25%) demonstrated increased tumor adherence at the porus acusticus intraoperatively, compared with 1 control (3%, P = .04). Long-term facial nerve function was similar between cases and controls (81% vs 84% House-Brackmann I-II function, P = 1.00).

CONCLUSION

Dural enhancement is present in approximately 10% of extracanalicular VS. Dural enhancement at the porus acusticus may represent hypervascularity, dural reaction, or infiltration, and portends increased tumor adherence and greater likelihood of subtotal resection to preserve facial nerve function. To our knowledge, this is the first series that reports the prevalence of this phenomenon in VS and the potential surgical implications. Recognition preoperatively may be valuable toward patient counseling.

Atypical medulloblastoma: A case series

Medulloblastoma is common in children as a tumor of midline posterior fossa, which arises from vermis and appears as a homogenously enhancing hyperdense mass on computed tomography scan and is associated with the clinical picture of posterior fossa syndrome. This unique clinic-radiological pattern in considered “typical” medulloblastoma, but medulloblastomas does not follow the typical clinic-radiological pattern in a significant number of children and adult cases. We review here the previous reports of atypical or uncommon features of medulloblastoma and add our very rare atypical cases of medulloblastomas to this list. Medulloblastoma should be considered in all midline posterior fossa tumors, hemisphere and cerebellopontine angle despite having clinical and radiological features suggestive of other tumors. Definitive diagnosis requires histologic confirmation in all cases.

Review of cerebellopontine angle medulloblastoma

Cerebellopontine angle (CPA) medulloblastomas (MB) are rare lesions with few cases previously described in the literature. We report two further cases of CPA MB. The patients were a 22-year-old man and a 26-year-old woman with a mass developing in the CPA. The preoperative radiological diagnosis was vestibular schwannoma in the first case and petrosal meningioma in the second case. The patients were operated on through a retrosigmoid approach. The intraoperative findings revealed an intra-axial tumour and the histological diagnosis was classic type of MB in both cases. We review the literature and discuss pathological and radiological features and possible pathogenesis of CPA MB, underlining the necessity to consider MB in the differential diagnosis of CPA lesions.

(1)H magnetic resonance spectroscopy and diffusion weighted imaging findings of medulloblastoma in 3.0T MRI: A retrospective analysis of 17 cases

¹H magnetic resonance spectroscopy and diffusion weighted imaging features of the cerebellar vermis in 17 medulloblastoma patients were retrospectively analyzed, and 17 healthy volunteers were selected as controls. ¹H magnetic resonance spectroscopy showed that in all 17 medulloblastoma patients, N-acetyl aspartate and creatine peaks were significantly decreased, the choline peak was significantly increased, and there was evidence of a myo-inositol peak. Further, 11 patients showed a low taurine peak at 3.4 ppm, five patients showed a lipid peak at 0.9–1.3 ppm, and three patients showed a negative lactic acid peak at 1.33 ppm. Compared with the control group, the ratios of N-acetyl aspartate/choline and N-acetyl aspartate/creatine were significantly decreased, and the ratio of choline/creatine was increased, in medulloblastoma patients. Diffusion weighted imaging displayed hyperintensity and decreased apparent diffusion coefficient in medulloblastoma patients. These findings indicate that ¹H magnetic resonance spectroscopy and diffusion weighted imaging are useful for qualitative diagnosis of medulloblastoma.

Meningeal tumors histologically mimicking meningioma

A number of meningeal neoplastic lesions may radiologically and clinically simulate meningioma. In the present paper, we review meningeal non-meningothelial tumors which may also mimic different histotypes of meningioma at the histological examination. Awareness that these lesions exist may facilitate their recognition and correct diagnosis, which is of fundamental importance for prognosis and an appropriate therapeutic approach. Histological and immunohistochemical clues for the differential diagnosis are discussed.

Magnetic resonance spectroscopy findings in non-enhancing desmoplastic medulloblastoma

Medulloblasoma is a common posterior fossa tumor seen in children and presents with some typical features like midline vermian location and fairly homogeneous enhancment. Desmoplastic variety of medulloblastoma is usually seen in the adults and is known to show some atypical features like lateral cerebellar location, variable enhancement, and early meningeal infilteration. Therefore medulloblastoma should always be considered in differential diagnosis of posterior fossa mass in adults even when typical imaging findings are not that of medulloblastoma. Enhancement pattern can be variable in these tumors varying from mild to striking. Occasionally, totally non-enhancing tumors are encountered, which can cause further diagnostic confusion. We describe the magnetic resonance (MR) and MR spectroscopy findings in a case of midline vermian mass, which did not show any enhancement on post-contrast images, and was subsequently proven to be desmoplastic medulloblastoma. On MR spectroscopy, the mass showed elevated choline peak consistent with mitotic lesion. No significant lipid lactate leak was seen, which is also consistent with the ususally homogeneous nature of these tumors. Moreover, it displayed taurine peak at 3.4 ppm which is considered fairly specific for medulloblastoma. Therefore, MR spectroscopy findings can be helpful in the diagnosis of medulloblastoma in adults when MR imaging findings can be nonspecific.

A review on dural tail sign

“Dural tail sign” (DTS) which is a thickening of the dura adjacent to an intracranial pathology on contrast-enhanced T1 MR Images, was first thought to be pathognomonic of meningioma, however, many subsequent studies demonstrated this sign adjacent to various intra- and extra-cranial pathologies and in spinal lesions. In this paper we outline the history, accompanying pathologies and the differentiation and probable pathophysiology of DTS. We also discuss whether we can predict tumoral involvement of the dural tail before surgery and whether the dural tail adjacent to a tumor should be resected.