Subependymoma
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]Associate Editor(s)-in-Chief: Mohamadmostafa Jahansouz M.D.[2]Sujit Routray, M.D. [3]
Pathophysiology
Pathogenesis
- Subependymoma arises from subependymal glial cells, although it can also arise from astrocytes from the subependymal plate, ependymal cells, and mixed ependymal and astrocytic cells.[1][2]
Gross Pathology
- Subependymoma is most commonly seen in the fourth ventricle, but can arise anywhere where there is ependyma. The distribution in the ventricular system is as follows:[3][2]
- Fourth ventricle: 50-60%
- Lateral ventricles (usually frontal horns): 30-40%
- Third ventricle: rare
- Central canal of the spinal cord: rare
- On gross pathology, subependymoma is characterized by a small, white to grey, firm, well circumscribed, solid, avascular mass attached to the ventricular wall by a narrow pedicle.[1][2]
Microscopic Pathology
- On microscopic histopathological analysis, subependymoma is characterized by microcystic spaces and bland appearing cells without appreciable nuclear atypia or mitoses. The nuclei tend to form clusters. No high grade features (mitoses, Ki-67 / MIBI index > 1.5%, necrosis) are present. Loose pseudorosettes are observed.[3]
Immunohistochemistry
- Subependymoma is demonstrated by positivity to tumor marker such as GFAP.[3]
- Also mixed populations of cells may be variably positive for:[4]
Differentiating Subependymoma from other Diseases
- Subependymoma must be differentiated from:[5][2]
- Neoplasms of the ventricular wall and septum pellucidum
- Neoplasms of the choroid plexus
- Others
Epidemiology and Demographics
Prevalence
- Subependymoma constitutes approximately 1% of all intracranial tumors.[1]
Age
- Subependymoma is a rare disease that tends to affect middle-aged adults and the elderly population (typically 5th to 6th decades).[6]
Gender
- Males are more commonly affected with subependymoma than females. The male to female ratio is approximately 2.3 to 1.[6]
Natural History, Complications and Prognosis
Natural History
- If left untreated, patients with subependymoma may progress to develop seizures and obstructive hydrocephalus.[7]
- Subependymoma is a slow growing tumor with an indolent course.
Complications
- Obstructive hydrocephalus is a common complication of subependymoma.[7]
Prognosis
History and Symptoms
History
- When evaluating a patient for subependymoma, you should take a detailed history of the presenting symptom (onset, duration, and progression), other associated symptoms, and a thorough family and past medical history review.
Symptoms
- Typically patients of subependymoma are asymptomatic and small lesions are discovered incidentally.
- Symptoms of subependymoma include:[9]
- Symptoms due to elevated intracranial pressure
- Neurological symptoms
- Seizures
- Sudden loss of awareness
- Transient loss of memory
CT
- Head CT scan is helpful in the diagnosis of subependymoma. On CT scan, subependymoma is characterized by:[10]
- Iso- and hypodense intraventricular mass
- Positive mass effect
- No enhancement
- If large, it may have cystic or even calcific components
- No vasogenic edema
MRI
- Brain MRI is helpful in the diagnosis of subependymoma. On MRI, subependymoma is characterized by:
| MRI component | Findings |
|---|---|
|
T1 weighted image |
|
|
T2 weighted image |
|
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T1 weighted image with contrast |
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Biopsy
- Biopsy of the subependymoma tumor, taken through a needle during a simple surgical procedure, helps to confirm the diagnosis.[11]
Treatment
- The predominant therapy for subependymoma is surgical resection.
References
- ↑ 1.0 1.1 1.2 1.3 Saad AF, Bidiwala SB, Layton KF, Snipes GJ, Opatowsky MJ (2013). "Fourth ventricular subependymoma presenting as worsening headache". Proc (Bayl Univ Med Cent). 26 (1): 52–4. PMC 3523772. PMID 23382616.
- ↑ 2.0 2.1 2.2 2.3 Jain A, Amin AG, Jain P, Burger P, Jallo GI, Lim M; et al. (2012). "Subependymoma: clinical features and surgical outcomes". Neurol Res. 34 (7): 677–84. doi:10.1179/1743132812Y.0000000064. PMC 4618470. PMID 22747714.
- ↑ 3.0 3.1 3.2 Pathology of subependymoma. Dr Bruno Di Muzio and A.Prof Frank Gaillard et al. Radiopaedia 2016. http://radiopaedia.org/articles/subependymoma. Accessed on January 12, 2016
- ↑ D'Amico RS, Praver M, Zanazzi GJ, Englander ZK, Sims JS, Samanamud JL; et al. (2017). "Subependymomas Are Low-Grade Heterogeneous Glial Neoplasms Defined by Subventricular Zone Lineage Markers". World Neurosurg. 107: 451–463. doi:10.1016/j.wneu.2017.08.009. PMID 28804038.
- ↑ Intraventricular neoplasms and lesions. Dr Henry Knipe and Dr Vinod G Maller et al. Radiopaedia 2016. http://radiopaedia.org/articles/intraventricular-neoplasms-and-lesions. Accessed on January 12, 2016
- ↑ 6.0 6.1 Epidemiology of subependymoma. Dr Bruno Di Muzio and A.Prof Frank Gaillard et al. Radiopaedia 2016. http://radiopaedia.org/articles/subependymoma. Accessed on January 12, 2016
- ↑ 7.0 7.1 Clinical presentation of subependymoma. Dr Bruno Di Muzio and A.Prof Frank Gaillard et al. Radiopaedia 2016. http://radiopaedia.org/articles/subependymoma. Accessed on January 12, 2016
- ↑ Prayson RA, Suh JH (1999). "Subependymomas: clinicopathologic study of 14 tumors, including comparative MIB-1 immunohistochemical analysis with other ependymal neoplasms". Arch Pathol Lab Med. 123 (4): 306–9. doi:10.1043/0003-9985(1999)123<0306:S>2.0.CO;2. PMID 10320142.
- ↑ KE, Changshu. "Subependymoma: a case report and the review of literatures". doi:10.3969/j.issn.1672-6731.2011.01.021.
- ↑ Radiographic features of subependymoma. Dr Bruno Di Muzio and A.Prof Frank Gaillard et al. Radiopaedia 2016. http://radiopaedia.org/articles/subependymoma. Accessed on January 12, 2016
- ↑ Diagnosis of subependymoma. Wikipedia 2016. https://en.wikipedia.org/wiki/Subependymoma. Accessed on January 8, 2016