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Neurology India
Medknow Publications on behalf of the Neurological Society of India
ISSN: 0028-3886 EISSN: 1998-4022
Vol. 58, Num. 5, 2010, pp. 768-770

Neurology India, Vol. 58, No. 5, September-October, 2010, pp. 768-770

Case Report

Germinoma of medulla

R Neelima1, A Mathew2, TR Kapilamoorthy3, VV Radhakrishnan1

1 Department of Pathology, Sree Chitra Tirunal Institute of Medical Sciences and Technology (SCTIMST), Trivandrum, Kerala, India
2 Department of Neurosurgery, Sree Chitra Tirunal Institute of Medical Sciences and Technology (SCTIMST), Trivandrum, Kerala, India
3 Department of Imaging Sciences and Interventional Radiology, Sree Chitra Tirunal Institute of Medical Sciences and Technology (SCTIMST), Trivandrum, Kerala, India

Correspondence Address:
V V Radhakrishnan
Department of Pathology, Sree Chitra Tirunal Institute of Medical Sciences and Technology (SCTIMST), Trivandrum, Kerala
India

Date of Acceptance: 21-Jul-2010

Code Number: ni10210

PMID: 21045508

DOI: 10.4103/0028-3886.72190

Abstract

Germinoma occurring in the medulla oblongata is extremely rare. We report a case of primary intracranial germinoma arising in the medulla oblongata of a 24-year-old postpartum female who presented with progressive weakness of upper and lower limbs, seventh nerve palsy, and decreased palatal movements. Her MR imaging showed a heterointense mass lesion in the posterior portion of upper medulla, the histology of which was reported as germinoma. Germ cell tumors should be considered in the differential diagnosis of tumors occurring in the brain stem.

Keywords: Germinoma, intraoperative frozen sections, medulla oblongata, rare, squash preparations

Introduction

Primary germ cell tumors (GCTs) account for 3% of all intracranial tumors of the central nervous system. [1] Intracranial GCTs mainly arise from the pineal region, suprasellar region, or basal ganglia. [2] However, GCTs are also reported to occur in unusual anatomical locations within the central nervous system which include the basal ganglia, thalamus, fourth ventricle, brainstem, and spinal cord. [3] It needs to be emphasized that GCTs occurring in these unusual locations pose considerable diagnostic challenges and could affect treatment modalities. In this report we describe the clinical, imaging and histopathological features of a case of germinoma arising from the medulla. Specific help that can be utilized in the pre-operative diagnosis as well as in the management of germinoma occurring in medulla are highlighted.

Case Report

A 24-year-old postpartum female was admitted in our institute with a history of headache of 1 year duration. The headache was holocranial, moderate to severe in intensity, and not associated with nausea or vomiting. During the course of illness, she had eight episodes of loss of consciousness. Each of these episodes were preceded by giddiness and followed by deviation of angle of mouth to right side as well as tonic posturing of both upper and lower limbs. Two months prior to admission she developed unsteadiness while walking. Three weeks prior to admission she also developed weakness of upper and lower limbs. There was no history of visual disturbances. Neurological examination revealed bilateral papilledema, left lower motor neuron type of seventh nerve palsy, decreased palatal movements on the right side, wasting of tongue muscles, deviation of tongue to the left side on protrusion, and exaggerated deep tendon reflexes. There were also features suggestive of cerebellar signs on the left side.

Computed tomography scan of the brain revealed a multilobulated lesion composed of solid and cystic components in the posterior fossa involving the fourth ventricle, medulla, vermis, and both cerebellar hemispheres. MR imaging revealed a well-defined lobulated heterogeneous mass lesion situated in the posterior portion of upper medulla encroaching the lower half of the fourth ventricle. The lesion showed well-defined T2 hyperintense cystic areas with iso- to hyperintense solid areas. A postcontrast study showed intense enhancement of the solid part of the lesion [Figure - 1].

The patient underwent surgery and the mass was approached via a midline suboccipital approach. During surgery the tumor was seen surfacing below vermis in midline, with the tonsils pushed laterally by the tumor. The tumor was seen in the lower half of fourth ventricle, with no plane of demarcation from the brainstem. Vermis and cerebellar hemispheres were free of tumor invasion. Frozen sections of the tissue provided during surgery were reported as glioma. Gross total decompression was done with part of tumor pseudocapsule left behind. Generous samples of the tissue were subjected to routine histopathological studies. Hematoxylin and eosin stains revealed a neoplasm composed of cells arranged in lobules and in a diffuse pattern and being intersected by fibrocollagenous connective tissue. The neoplastic cells had abundant granular cytoplasm and a vesicular nucleus. Dense lymphomononuclear aggregates were seen within the lobules as well as in fibrovascular connective tissue septa [Figure - 2]a. In none of the microscopic fields other germ cell elements were demonstrated. These above features were classical for germinoma. A majority of the cells yielded positive immunostaining for placental alkaline phosphatase thus confirming the diagnosis of germinoma [Figure - 2]b.

Discussion

Intracranial germ cell tumors are regarded as morphological homologues of germinal neoplasms arising from the gonadal and extragonadal locations. The precise histogenesis of intracranial germ cell tumors is not well defined. However three possible mechanisms are proposed. (a) Germ cell tumors are assumed to represent the neoplastic off springs of primordial germ cells that migrate in an aberrant fashion. (b) Germ cell tumors can arise from a variety of displaced embryonic tissues that previously occur in developing neural tube. (c) These tumors could also originate from pleuripotential embryonic stem cells. [4] It is thought to be due to entrapment of migrating totipotential cells during early period of rostral neural tube development. [5] An embryonic stem cell origin could account for the occurrence of certain germ cell tumors such as yolk sac tumor and embryonal carcinoma. Most of the germ cell tumors are sporadic and no definite genetic predilection have been so far established. However intracranial germ cell tumors are known to be associated with Klinefelters syndrome as well as neurofibromatosis I. [6] Intracranial GCTs occurring in the medulla oblongata are extremely rare. A review of literature till 2009 indicated that there were seven documented cases of germinomas that occurred in medulla oblongata. [5],[6],[7],[8],[9],[10],[11] The first documented case of germ cell tumor of medulla oblongata was by Hashimoto et al in 1992. [6]

Earlier published cases of GCTs occurring in medulla with relevant clinical and imaging features are summarized in [Table - 1]. From the review, it is apparent that the neuroimaging features in all these seven cases were interpreted as astrocytic or ependymal neoplasms. In none of these cases including the present case, a diagnosis of GCT was made. The diagnosis of germinoma in all these seven cases could be made only after proper histopathological examination of the tissue provided.

One of the objectives in neurosurgical management of intracranial germ cell tumors is to minimize the neurological deficits that can occur following surgery. In the vast majority of patients an accurate preoperative diagnosis by neuroimaging is not possible owing to rarity of this tumor. Secondly there are no definite imaging features that would distinguish germ cell tumors from other neoplastic lesions arising in this site. An accurate diagnosis given during frozen sections or squash preparations during the surgical procedure is extremely useful to the surgeon as the management protocol can be altered based on the diagnosis. It will also be useful as these patients need not be subjected to a major neurosurgical procedure thereby reducing the patient's hospital stay duration to a significant extent. An accurate diagnosis of germinoma assumes greater clinical significance as this neoplasm responds well to radiotherapy with good clinical recovery.

Germinoma can be associated with other germ cell elements such as Yolk sac tumor, embryonal carcinoma, and choriocarcinoma. Owing to sampling limitations in frozen sections or intraoperative squash preparations, these other germ cell elements may not be included and hence the diagnosis can be missed. Hence preoperative measurement of tumor markers-PLAP, AFP, and HCG in CSF specimen will detect the co-existence of the other germ cell elements in the tumor. This has great clinical relevance in the early diagnosis as well as management of germ cell tumors. [3]

Germinomas have a tendency to disseminate along the CSF pathway and hence routine CSF cytology for tumor cells can also be regarded as one of the preoperative diagnostic modalities. A complete CNS evaluation including brain and spine MRI for the presence of multiple fluid levels (hemorrhages) as well as cysts with solid areas can give us a clue regarding the presence of mixed germ cell elements in the tumor. [12]

Conclusion

Though rare germ cell tumors must be considered as a differential diagnosis of intrinsic brain stem tumors, an accurate preoperative diagnosis of intracranial germinoma is extremely useful for the management and prognosis of the patient. Even though histopathological diagnosis remains the "cornerstone" in making the diagnosis, diagnosis by means of intraoperative frozen sections or squash preparations helps in deciding further treatment options instead of complete decompression of the tumor. This can be supported by the estimation of tumor markers in CSF and serum, CSF cytology study as well as correlating with the findings in CT and MRI. [12]

Acknowledgement

I express my sincere gratitude to the Director of our institute for permitting me to publish this article.

References

1.Yasunobu I, Katsuyoshi M, Hiroyasu S, Masyoshi K. Intramedullary spinal cord germinoma: Case report and review of the literature. Neurosurgery 1996;38:187-94.  Back to cited text no. 1    
2.Koizumi H, Oka H, Utsuki S, Sato S, Tanizaki Y, Shimizu S, et al. Primary germinoma arising from the midbrain. Acta Neurochir 2006;148:1197-200.  Back to cited text no. 2    
3.Koh EJ, Phi JH, Park SH, Kim IO, Cheon JE, Wang KC, et al. Mixed Germ cell tumor of the Midbrain: Case report. J Neurosurg Pediatr 2009;4:137-42.  Back to cited text no. 3    
4.Paul Kleihues, Webster K. Cavenee, International agency for research on cancer. World Health Organisation - Pathology and genetics of tumours of the nervous system. 2000.  Back to cited text no. 4    
5.Yen PS, Chen AS, Chen CJ, Chuang HL, Scott RM. Primary medulla oblongata germinoma: Case report. J Neurooncol 2003;62:339-42.  Back to cited text no. 5    
6.Hashimoto M, Hatasa M, Shinoda S, Masuzawa T. Medulla oblongata germinoma in association with Klinefelter syndrome. Surg Neurol 1992;37:384-7.  Back to cited text no. 6  [PUBMED]  
7.Saito A, Yamashita T, Ishiwata Y, Hirata K, Kubuwara T. A case of germinoma of the fourth ventricle. Shoni No shinkei 1983;8:43-8.  Back to cited text no. 7    
8.Poungvarin N, Nimmannitya J, Issaragrisil R, Sangruchi T. Brainstem germinoma presenting as intermittent apnoea: A rare entity: Report of one patient and review of literature. J Med Assoc Thai 1991;74:55-60  Back to cited text no. 8    
9.Tashiro T, Yoshida J, Wakabayasi T, Sugita K. Primary intracranial germinoma involving the medulla oblongata: Neurol Med Chir (Tokyo) 1993;33:251-4.  Back to cited text no. 9    
10.Sugiyama K, Uozumi T, Sogabe S, Arita K, Meada H, Ikawa F. Germinoma of the medulla oblongata: Case report; Neurol Med Chir (Tokyo) 1994;34:291-4.  Back to cited text no. 10    
11.Nakajima H Iwai Y, Yamanaka K, Yasui T, Kishi H. Primary intracranial germinoma in the medulla oblongata: Surg Neurol 2000;53:448-51.  Back to cited text no. 11    
12.Echevarría ME, Fangusaro J, Goldman S. Pediatric central nervous system germ cell tumors: A review. Oncologist 2008;13:690-9.  Back to cited text no. 12    

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