|Year : 2007 | Volume
| Issue : 2 | Page : 82-84
Fourth ventricular medullomyoblastoma: A case report with review of literature
P Patel, S Annapurneswari, S Ghosh
Department of Neurosurgery, Apollo Specialty Hospital, Chennai, India
Department of Neurosurgery, Apollo Specialty Hospital, 320- Anna Salai, Chennai - 600 035
Source of Support: None, Conflict of Interest: None
| Abstract|| |
Medullomyoblastoma (MMB) is a rare embryonal cerebellar neoplasm with both primitive neuroectodermal and striated muscle components. It occurs exclusively in children. It typically arises from the cerebellar vermis. There are only 54 case reports in the published literature. We report an additional case of a 7-year-old boy with fourth ventricular MMB that is unique in its site of origin, intratumoral hemorrhage and calcification.
Keywords: Fourth ventricular tumor, medullomyoblastoma
|How to cite this article:|
Patel P, Annapurneswari S, Ghosh S. Fourth ventricular medullomyoblastoma: A case report with review of literature. J Pediatr Neurosci 2007;2:82-4
| Introduction|| |
Medullomyoblastoma is a rare embryonal cerebellar neoplasm and occurs exclusively in children. ,,,,,, Marinesco and Goldstein in 1933 first described the biphasic nature of MMB with both a primitive neuroectodermal and striated muscle components.  Since then, there have been only 54 additional case reports in the literature. ,,,,,,,, MMB is a unique variant of medulloblastoma with more aggressive nature. , The histogenesis of the myogenic component of MMB is still a subject of controversy. ,,,,,
| Case Report|| |
A 7-year-old boy presented with complaints of imbalance while walking, of 3 months' duration . Since 15 days, he had difficulty in sitting due to severe truncal ataxia and inability to see objects on the right side. He had multiple episodes of vomiting with history of on-and-off nasal regurgitation and moderate-to-severe occipital headache since last 1 week. On examination he had bilateral papilledema, right side conjugate gaze paresis; gaze evoked jerky horizontal nystagmus with torsion component, more on looking towards the right side. Lower cranial nerves (ninth and tenth) were minimally affected. He had severe truncal ataxia with bilateral cerebellar signs and normal power in all the four limbs.
CT showed large midline mass in the posterior fossa with intrinsic calcification, hemorrhage and obstructive hydrocephalus [Figure - 1]A, B. MRI brain revealed large (4 cm × 5 cm × 5.5 cm) mass in the fourth ventricle involving the ependymal lining and extending from cerebral aqueduct to cerebellomedullary junction craniocaudally with extension into foramen of Magendie and Luscha with obstructive hydrocephalus. T1WI showed heterogeneously hypo-intense mass with heterogeneous enhancement with area of necrosis [Figure - 2]A, C. The tumor was compressing and displacing brain stem anteriorly against clivus with superior and inferior cerebellar herniation [Figure - 2]D, F. T2WI showed hypo-intense to hyperintense signals [Figure - 2]B, E. Right side ventriculo-peritoneal shunt was done. He underwent midline sub-occipital craniotomy and total excision of tumor. Vermis was stretched and tumor was soft to firm, moderately vascular with partly hemorrhagic and necrotic suckable area. Tumor was occupying the fourth ventricle and extending into the aqueduct, foramen of Magendie and Luscha.
Histopathology revealed pattern-less sheets of undifferentiated cells with hyperchromatic pleomorphic nuclei and bundles of spindled cells with abundant eosinophilic cytoplasm [Figure - 3]A. Few definite strap cells with striation were present. Numerous mitotic figures, areas of necrosis and small foci of calcification were present. Immunohistochemical study was positive for desmin [Figure - 3]B, synaptophysin [Figure - 3]C with focal positivity for GFAP [Figure - 3]D and chromogranin.
In the immediate postoperative period, he had mild weakness of left side limbs, which improved gradually along with marked improvement in ataxia. Radiation therapy with a total dose of 4950 cGy on the primary site and a total of 3750 cGy to the whole cranium was given. Next he underwent five cycles of chemotherapy with vincristine, CCNU, cisplatin and methylprednisolone. At follow-up of 8 months, there is no evidence of tumor on CT brain [Figure - 4]A, B. He is able to walk with minimal support with improving right side gaze paresis.
| Discussion|| |
Medullomyoblastoma (MMB) is a rare embryonal tumor, well described by Russel and Rubinstein and also by Burger and Scheithauer as a variant of medulloblastoma. ,,,,,,, Marinesco and Goldstein first described MMB in 1933; and since then, there have been only 54 additional case reports in the literature. ,,,,,,,, Microscopically MMB is biphasic, containing both a primitive neuroectodermal and striated muscle components. ,,,,,,,,
MMB arises exclusively within the infratentorial compartment, and its typical location is the cerebellar vermis. ,, Tumor with extension or invasion of cerebellar hemisphere, brain stem, fourth ventricle and cerebellopontine angle has also been reported. ,,, Sang-Yoo Park et al. have reported the only case of MMB arising in the cerebellopontine angle.  According to our literature review, this is the first case of purely fourth ventricular MMB with intratumoral hemorrhage and calcification.
Several hypotheses have been put forward regarding the origin of the rhabdomyoblastic component in MMB. ,,,,, First proposed by Russel and Rubinstein and later on supported by Misugi and Liss, the coexistence of areas of well-differentiated teratoma has been viewed as evidence that MMB may constitute a variant of malignant teratoma. ,,, However, the usual absence of other tissue elements argues strongly against this hypothesis. Walter and Brucher in 1979 postulated that myogenic component derives from the multipotential endothelial cells.  According to Wills et al., myoblastoma component originates from the pluripotential mesenchymal cells present in or near the tumor.  The last hypothesis by Lewis suggests that primitive neuroectodermal cells are pluripotential and possess myogenesis capabilities. 
Of the 54 cases previously reported in the literature, nearly 90% were aged less than 10 years and only 3 were adults. ,,, The male-to-female ratio was 3.9:1. Biological behavior, clinical characteristics and metastatic pattern of MMB are nearly similar to those of classical medulloblastoma; this was supported by the two largest reported series of MMB by Mahapatra et al. (n=7) and Helton et al. (n=6). ,,, The clinical symptoms usually last for a short period - from a few weeks to months before diagnosis. ,, In our case worsening of the symptoms may be due to intratumoral hemorrhage, which is not a common finding.
In the published cases of MMB, imaging has been limited predominantly to CT scan, with only seven cases studied with MRI. ,,,,, On CT imaging, MMB resembles hyperdense infratentorial mass with variable enhancement and frequent association with hydrocephalus. On MRI, tumor reveals iso- to hypo-intense signal on T1WI, with variable T2WI signals. Tumors exhibit variable enhancement, and nearly 50% cases have large area of necrosis. ,,,
Histopathologically, all MMBs presented in the literature have been biphasic with focal myogenic differentiation. ,,,, The additional muscle component consists of striated muscle fibers collected in bundles or around vessels. Bundles of spindled cells with abundant eosinophilic cytoplasm are sometimes accompanied by tadpole-shaped cells and/ or strap cells with discernible cross striations. Immunohistochemically, muscle cells are reactive for myoglobin and myosin. ,,,,,,, On electron microscopy, the primitive myoblastic cells have rudimentary 'Z line'-like densities.  Though biphasic in nature, MMB clearly harbors significant heterogeneity in the form of neuronal/ ganglionic differentiation or glial/ astrocytic differentiation and pigmented/ melanotic cells. ,, In a series of six cases, Helton et al. summarized frequent association between biphasic nodularity and the presence of discrete rhabdomyoblastic and primitive neuroectodermal islands. 
Though there are some differences in treatment among published cases, general approach remains similar - consisting of radical excision, craniospinal irradiation and chemotherapy. ,,,, In some cases, chemotherapy was indicated only when there was tumor recurrence or dissemination of tumor in the CSF. Despite all possible treatment modalities used in the published cases, postoperative survival of longer than 1 year was reported in only nine patients. ,,, Helton et al. reported the longest postoperative survival of 187 months. 
| Conclusion|| |
Medullomyoblastoma is a unique variant of medulloblastoma with more aggressive nature. Though rare, it can present as fourth ventricular tumor with intratumoral hemorrhage and calcification. Immunohistochemical findings help to differentiate MMB from other tumors with similar location and radiological findings.
| References|| |
|1.||Marinesco G, Goldstein M. The south unites forms anatomique, non encore decrite, of medulloblastome, Medullo-myoblastome. Ann Anat Pathol 1933;10:513-25. |
|2.||Helton KJ, Fouladi M, Boop FA, Perry A, Dalton J, Kun L, et al . Medullomyoblastoma: A radiographic and clinicopathologic analysis of six cases and review of the literature. Cancer 2004;101:1445-54. [PUBMED] [FULLTEXT]|
|3.||Park SY, Kim JH, Kim KT, Kim YJ, Kim TH, Hwang K, et al . A case of Medullomyoblastoma of cerebellopontine angle mimicking acoustic neuroma. Yonsei Med J 2004;45:719-22. [PUBMED] [FULLTEXT]|
|4.||Walter GF, Brucher JM. Ultrastructural study of medullomyoblastoma. Acta Neuropathol (Berl) 1979;48:211-4. [PUBMED] |
|5.||Mahapatra AK, Sinha AK, Sharma MC. Medullomyoblastoma: A rare cerebellar tumor in children. Childs Nerv Syst 1998;14:312-6. [PUBMED] [FULLTEXT]|
|6.||Rao C, Friedlander ME, Klein E, Anzil AP, Sher JH. Medullomyoblastoma in an adult. Cancer 1990;65:157-63. [PUBMED] |
|7.||Lata M, Mahapatra AK, Sarkar C, Roy S. Medullomyoblastoma: A case report. Indian J Cancer 1989;26:240-6. |
|8.||Cheema ZF, Cannon TC, Leech R, Brennan J, Adesina A, Brumback RA. Medullomyoblastoma: Case report. J Child Neurol 2001;16:598-9. [PUBMED] |
|9.||Arunkumar MJ, Chacko G, Chandi SM, Chandi MJ. Medullomyoblastoma: A case report. Neurol India 1999;47:55-7. |
|10.||Russell DS, Rubinstein LJ. Pathology of tumours of the nervous system. Arnold E, editor. Great Britain; 1989. p. 687-9. |
|11.||Lewis AJ. Medulloblastoma with striated muscle fibers: Case report. J Neurosurg 1973;38:642-6. [PUBMED] |
|12.||Chowdhury C, Roy S, Mahapatra AK, Bhatia R. Medullomyoblastoma: A teratoma. Cancer 1985;55:1495-500. [PUBMED] |
|13.||Misugi K, Liss L. Medulloblastoma with cross striated muscle: A fine structural study. Cancer 1970;25:1279-85. [PUBMED] |
|14.||Dickson DW, Hart MN, Menezes A, Cancilla PA. Medullomyoblastoma with glial and rhabdomyoblastic differentiation: A myoglobin and glial fibrillary acidic protein immunohistochemical and ultrastructural study. J Neuropathol Exp Neurol 1983;42:639-47. [PUBMED] |
|15.||Holl T, Kleihues P, Yasargil MG, Wiestler OD. Cerebellar medullomyoblastoma with advanced neuronal differentiation and hamartomatous component. Acta Neuropathol (Berl) 1991;82:408-13. |
[Figure - 1], [Figure - 2], [Figure - 3], [Figure - 4]