Medulloepithelioma is a rare, primitive, fast-growing brain tumour thought to stem from cells of the embryonic medullary cavity.[1] Tumours originating in the ciliary body of the eye are referred to as embryonal medulloepitheliomas,[1] or diktyomas.[2]
Medulloepithelioma | |
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Histopathology of medulloepithelioma showing characteristic neural tube like strands. | |
Specialty | Neurosurgery, Neuro-oncology |
A highly malignant undifferentiated primitive neuroepithelial tumour of children, medulloepithelioma may contain bone, cartilage, skeletal muscle, and tends to metastasize extracranially.[2]
Medulloepithelioma have been reported to occur in the cerebral hemispheres, brainstem, cerebellum, and peripheral sites.[3][4][5][6]
Due to rapid growth of the tumour, patients typically present with increased intracranial pressure, seizures, and focal neurologic signs.[7]
Imaging studies such as Computerized Tomography (CT) and Magnetic Resonance Imaging (MRI) can aid diagnosis. Medulloepithelioma appears isodense or hypodense with variable heterogeneity and calcification on non-contrast CT scan, and enhances with contrast.[3] This radiographical finding is consistent with a primitive neuroectodermal tumour, especially in children.[6] Blood studies and imaging studies of the abdomen may be used to detect metastases.[6]
Needle aspiration biopsy can be used to aid diagnosis.[6] Definitive diagnosis requires histopathological examination of surgically excised tumour tissues.[citation needed]
Histologically, medulloepithelioma resemble a primitive neural tube and with neuronal, glial and mesenchymal elements.[8][9] Flexner-Wintersteiner rosettes may also be observed.[10]
Immunohistochemically, neural tube-like structures are vimentin positive in the majority of medulloepitheliomas.[11] Poorly differentiated medulloepitheliomas are vimentin negative.[citation needed]
Medulloepithelioma was originally classified as the most primitive neoplasm of the Central Nervous System (CNS) by Bailey and Cushing in 1926.[4] Rorke et al.[12] classified this tumour into two subtypes:
Total resection of the tumour, followed by radiation therapy is the standard treatment modality.[3] Medulloepithelioma of the ciliary body may necessitate enucleation of the eye.[13][14] Radiation therapy alone may prolong survival.[3] Aggressive chemotherapy with autologous bone marrow transplant is used for metastatic medulloepitheliomas.[6]
Medulloepithelioma carries a dismal prognosis with a median survival of 5 months.[3][15][16][17]
Medulloepithelioma most commonly affect children between 6 months and 5 years; rarely, this tumour may occur congenitally or beyond this age range.[8][18][19] Incidence is equal in males and females.[3]