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Synonyms and Keywords: Medullary epithelioma
Medulloepithelioma is a rare, primitive, fast-growing brain tumor thought to stem from cells of the embryonic medullary cavity. Tumors originating in the ciliary body of the eye are referred to as embryonal medulloepitheliomas or diktyomas. Medulloepithelioma was first discovered by Bailey and Cushing in 1926. The pathogenesis of medulloepithelioma is characterized by highly malignant undifferentiated primitive neuroepithelial tumor. Tumors generally originate in the ciliary body of the eye. It most commonly manifests in the cerebral hemispheres, brainstem, cerebellum, and in peripheral sites. Medulloepithelioma arises from primitive medullary epithelium, which is normally involved in the embryonic formation of CNS. Medulloepithelioma is more commonly observed among patients between 6 months and 5 years old. On CT, findings of medulloepithelioma, include an isodense or hypodense lesion with variable heterogeneity and calcification. Surgery is the mainstay of therapy for medulloepithelioma. Total resection in conjunction with radiation therapy is the most common approach to the treatment of medulloepithelioma.
Medulloepithelioma was first discovered by Bailey and Cushing in 1926.
Medulloepithelioma may be classified into 3 groups:
- Medulloepithelioma not otherwise specified
- Medulloepithelioma with differentiation into astrocytes, oligodendrocytes; ependymal cells
- Medulloepithelioma with neuronal cells, other cells (melanocytes, mesenchymal cells), and mixed cellular elements
The pathogenesis of medulloepithelioma is characterized by:
- A highly malignant undifferentiated primitive neuroepithelial tumor
- Tumors generally originate in the ciliary body of the eye
- Located in cerebral hemispheres, brainstem, cerebellum, and peripheral sites
The germline DICER1 gene mutation has been associated with the development of medulloepithelioma.
There are no characteristic gross pathology findings associated with medulloepithelioma.
On microscopic histopathological analysis, characteristic findings of medulloepithelioma may include:
- Small round blue cell tumor
- Focal differentiation into astrocytic, neuronal or ependymal phenotypes possible
- May have true rosettes (slit-like/oval)
- Growth in streams or palisades
- Vascular endothelial proliferations
- Fibrillary background in tumors with advanced neuronal maturation
- Variable mitotic activity
On immunohistopathological analysis, characteristic findings of medulloepithelioma may include:
- Positive S-100
- Positive INI1
- Positive LIN28
The cause of medulloepithelioma is unknown.
Differentiating Medulloepithelioma from Other Diseases
Medulloepithelioma must be differentiated from other diseases that cause vision loss, ocular mass, and headache such as:
Epidemiology and Demographics
Medulloepithelioma is a rare disease.
Medulloepithelioma is most commonly observed among patients between 6 months and 5 years old.
Medulloepithelioma affects men and women equally.
There is no racial predilection for medulloepithelioma.
There are no known associated risk factors in the development of medulloepithelioma.
Natural History, Complications and Prognosis
- Patients with medulloepithelioma may be initially asymptomatic. Early clinical features include vision loss, irritability, and neurological deficit. If left untreated, patients with medulloepithelioma may progress to mortality.
Common complications of medulloepithelioma include:
The prognosis of medulloepithelioma is generally poor; the median survival time of patients with medulloepithelioma is approximately 5 months.
History & Symptoms
Medulloepithelioma is usually asymptomatic. Symptoms of medulloepithelioma may include:
Patients with medulloepithelioma usually are well-appearing. Physical examination may be remarkable for:
- Paralysis of a limb (monoparesis) or hemiparesis
- Paralysis of the head and eye movements
- Total loss of vision
There are no specific laboratory findings associated with medulloepithelioma.
On CT, findings of medulloepithelioma include isodense or hypodense lesions with variable heterogeneity and calcification.
There is no medical treatment for medulloepithelioma; the mainstay of therapy is surgery.
Surgery is the mainstay of therapy for medulloepithelioma. Total resection in conjunction with radiation therapy is the most common approach to the treatment of medulloepithelioma.
There are no primary preventive measures available for medulloepithelioma.
- McGraw-Hill Concise Dictionary of Modern Medicine. © 2002 by The McGraw-Hill Companies, Inc.
- Definition of Medulloepithelioma, from Online Medical Dictionary. Retrieved 7 January 2010.
- Russel DS, Rubinstein LJ. Pathology of tumors the nervous system, 5th ed. Baltimore: Williams & Wilkins 1989; pp. 247-51.