Medulloepithelioma: Difference between revisions
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==References== | ==References== | ||
Revision as of 21:31, 29 April 2016
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1] Associate Editor(s)-in-Chief: Maria Fernanda Villarreal, M.D. [2]
Synonyms and keywords: Medullary epithelioma;
Overview
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.[1][2] 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, and normally located in cerebral hemispheres, brainstem, cerebellum, and peripheral sites
Historical Perspective
- Medulloepithelioma was first discovered by Bailey and Cushing, in 1926.
Classification
- Medulloepithelioma may be classified into 3 groups:
- Medulloepithelioma not otherwise specified
- Medulloepithelioma with differentiation into astrocytes, oligodendrocytes; ependymal cells
- Medulloepithelioma with neuronal cells; others (melanin, mesenchymal cells); and mixed cellular elements
Pathophysiology
- 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
- Medulloepithelioma arises from primitive medullary epithelium, which is normally involved in the embryonic formation of CNS.
- The germline DICER1 gene mutation has been associated with the development of medulloepithelioma.
- On gross pathology, characteristic findings of medulloepithelioma, include:
- There are no remarkable findings
- On microscopic histopathological analysis, characteristic findings of medulloepithelioma, 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 possible
- Vascular endothelial proliferations.
- Fibrillary background in tumours with advanced neuronal maturation
- Variable mitotic activity
- On inmunohistochemistry, characteristic findings of medulloepithelioma, include:
- Positive S-100
- Positive INI1
- Positive LIN28
Causes
- The causes of medulloepithelioma are not fully understood.
Differentiating Medulloepithelioma from Other Diseases
- Medulloepithelioma must be differentiated from other diseases that cause vision loss, eye mass, and headache, such as:
- Brain tumors
- Intraocular lymphoma
- Anterior chamber cyst
Epidemiology and Demographics
- Medulloepithelioma is a rare disease.
Age
- Medulloepithelioma is more commonly observed among patients aged between 6 months and 5 years old.[3]
- Medulloepithelioma is more commonly observed among children.
Gender
- Medulloepithelioma affects men and women equally.
Race
- There is no racial predilection for medulloepithelioma.
Risk Factors
- There are no associated risk factors in the development of medulloepithelioma.
Natural History, Complications and Prognosis
- In some cases 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 develop serious neurological deficit.
- Common complications of medulloepithelioma, include:
- Optical nerve injury
- Increased intracranial pressure
- Prognosis is generally poor, and the median survival time of patients with medulloepithelioma is approximately 5 months.
Diagnosis
Symptoms
- Medulloepithelioma is usually asymptomatic.
- Symptoms of medulloepithelioma may include the following:
- Headache
- Fatigue
- Tinnitus
Physical Examination
- Patients with medulloepithelioma usually appear [general appearance].
- Physical examination may be remarkable for:
- Paralysis of a limb (monoparesis) or a larger area on one side of the body (hemiparesis)
- Paralysis head and eye movements
- Total loss of vision
Laboratory Findings
- There are no specific laboratory findings associated with medulloepithelioma.
Imaging Findings
- On CT, findings of medulloepithelioma, include:
- The lesion is isodense or hypodense with variable heterogeneity and calcification
- On MRI, findings of medulloepithelioma, include:
- The image below demonstrates an example of medulloepithelioma
Treatment
Medical Therapy
- There is no treatment for medulloepithelioma; the mainstay of therapy is surgery.
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.
Prevention
- There are no primary preventive measures available for medulloepithelioma.
References
- ↑ 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.