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Molecular Testing for Schwannoma

Last updated March 3, 2017

Approved by: Krish Tangella MD, MBA, FCAP

Molecular Testing for Schwannoma is a genetic test that is helpful in aiding a diagnosis of schwannoma.

What are other Names for this Test? (Equivalent Terms)

  • Gene Mutation Analysis for Schwannoma
  • Test for Molecular Diagnosis of Schwannoma

What is Molecular Testing for Schwannoma? (Background Information)

  • Molecular Testing for Schwannoma is a genetic test that is helpful in aiding a diagnosis of schwannoma. The lab test results may also be subsequently useful in taking appropriate treatment decisions
  • Schwannomas are a group of tumors that arise from the Schwann cells around the nerves; these tumors are essentially nerve sheath tumors. They are commonly seen in young, middle-aged, and slightly older adults
  • There are several histological variants of schwannomas, which include:
    • Cellular schwannoma
    • Plexiform schwannoma
    • Microcystic (reticular) schwannoma
  • In case of the presence of multiple schwannomas (in a minority of cases), the risk factors include the presence of neurofibromatosis type 2 (NF2) and a positive family history of schwannoma
  • Schwannomas may be asymptomatic (in many cases) or symptomatic. The signs and symptoms are commonly based upon the location of the tumor and can be wide-ranging

The cause of schwannoma (including its variants) is due to genetic mutations. Currently, studies indicate defects in the following genes:

  • NF2

Additionally, the following chromosomal anomalies may be noted:

  • Monosomy or partial loss of material on chromosome 22

The above genetic abnormalities can be detected using molecular studies, which may play a significant role in identifying the tumor type, and in some cases, helping the healthcare provider take appropriate treatment decisions.

The molecular testing, in general, can be performed using a variety of methods. Some of these methods include:

  • In situ hybridization technique, such as fluorescence in situ hybridization (FISH)
  • Immunohistochemistry (IHC)
  • Next-generation sequencing (NGS)
  • Polymerase chain reaction (PCR)
  • Comparative genomic hybridization (CGH)
  • Karyotyping including spectral karyotyping
  • mRNA analysis
  • Tissue microarrays (TMAs)
  • Southern blot test
  • Northern blot test
  • Western blot test
  • Eastern blot test

The methodology used for schwannoma may vary from one laboratory to another. 

Note: Molecular testing has limitations due to the molecular method and genetic mutational abnormalities being tested. This can affect the results on a case-by-case basis. Consultation with your healthcare provider will help in determining the right test and right molecular method, based on individual circumstances.

What are the Clinical Indications for performing the Molecular Testing for Schwannoma Test?

Molecular Testing for Schwannoma is undertaken in the following situations: 

  • To assist (and in some cases, confirm) the initial diagnosis of schwannoma
  • To distinguish other tumors/conditions that have similar histological features, when examined by a pathologist under the microscope
  • To help in determining treatment options
  • To confirm recurrence of the tumor: Tumor recurrence can either be at the original tumor site, or at a distant location (away from the initial site)

How is the Specimen Collected for Molecular Testing for Schwannoma?

Following is the specimen collection process for Molecular Testing for Schwannoma:

The specimen sample requirements may vary from lab to lab. Hence, it is important to contact the testing lab for exact specimen requirements, before initiating the testing process.

  • Sample required:
    • Fresh tumor tissue during biopsy
    • Formalin-fixed paraffin-embedded solid tumor tissue (FFPE tumor tissue), often referred to as paraffin block of the tumor
    • Unstained tissue slides
  • Process of obtaining the sample: As outlined by the laboratory testing facility
  • Preparation required: As outlined by the laboratory testing facility


  • Depending on the location of testing, it may take up to 2 weeks’ turnaround time, to obtain the test results
  • Occasionally, additional samples may be required to either repeat the test or to perform follow-up testing
  • Many hospitals preserve the paraffin blocks for at least 7 years. In general, older paraffin blocks (over 5 years) may affect the detection of specific mutations, due to degradation of the tumor specimen over time

Cost of Molecular Testing for Schwannoma:

  • The cost of the test procedure depends on a variety of factors, such as the type of your health insurance, annual deductibles, co-pay requirements, out-of-network and in-network of your healthcare providers and healthcare facilities
  • In many cases, an estimate may be provided before the test is conducted. The final amount may depend upon the findings during the test procedure and post-operative care that is necessary (if any)

What is the Significance of the Molecular Testing for Schwannoma Result?

The significance of Molecular Testing for Schwannoma is explained:

  • Presence of a positive test result helps aid, and in some cases, confirm the diagnosis of schwannoma
  • The result can help exclude other tumors with similar histological features
  • It can help determine the prognosis of the patient
  • In some cases, the test results may help in taking treatment decisions

The laboratory test results are NOT to be interpreted as results of a "stand-alone" test. The test results have to be interpreted after correlating with suitable clinical findings and additional supplemental tests/information. Your healthcare providers will explain the meaning of your tests results, based on the overall clinical scenario.

Additional and Relevant Useful Information:

  • Many laboratories may not have the capability to perform this test. Only highly-specialized labs with advanced facilities and testing procedures may perform this test
  • Additional mutations are still being discovered in many of these tumors. This may further contribute towards tumor diagnosis and treatment. Please consult with your healthcare provider for any information updates

Certain medications that you may be currently taking may influence the outcome of the test. Hence, it is important to inform your healthcare provider of the complete list of medications (including any herbal supplements) you are currently taking. This will help the healthcare provider interpret your test results more accurately and avoid unnecessary chances of a misdiagnosis.

What are some Useful Resources for Additional Information?

The following DoveMed website link is a useful resource for additional information:


Please visit our Laboratory Procedures Center for more physician-approved health information:


References and Information Sources used for the Article:

https://ghr.nlm.nih.gov/primer/testing/genetictesting (accessed on 02/17/2017)

https://www.cdc.gov/mmwr/preview/mmwrhtml/rr5806a1.htm (accessed on 02/17/2017)

http://www.nature.com/gim/journal/v10/n5/full/gim200852a.html (accessed on 02/17/2017)

http://pediatrics.aappublications.org/content/106/6/1494 (accessed on 02/17/2017)

https://rarediseases.info.nih.gov/diseases/4767/benign-schwannoma (accessed on 02/17/2017)

http://www.nfauk.org/what-is-neurofibromatosis/schwannomatosis/ (accessed on 02/17/2017)

http://www.neuro-oncologyassociates.com/Pages/schwannoma.aspx (accessed on 02/17/2017)

Helpful Peer-Reviewed Medical Articles:

Carrano, A. V., et al. Measurement and purification of human chromosomes by flow cytometry and sorting. Proceedings of the National Academy of Sciences 76, 1382–1384 (1979)

Drets, M. E., & Shaw, M. W. Specific banding patterns of human chromosomes. Proceedings of the National Academy of Sciences 68, 2073–2077 (1971)

Druker, B. J. Perspectives on the development of a molecularly targeted agent. Cancer Cell 1, 31–36 (2002)

Parra, I., & Windle, B. High resolution visual mapping of stretched DNA by fluorescent hybridization. Nature Genetics 5, 17–21 (1993) doi:10.1038/ng0993-17

Pinkel, D., et al. High resolution analysis of DNA copy number variation using comparative genomic hybridization to microarrays. Nature Genetics 20, 207–211 (1998) doi:10.1038/2524

Speicher, M. R., et al. Karyotyping human chromosomes by combinatorial multi-fluor FISH. Nature Genetics 12, 368–375 (1996) doi:10.1038/ng0496-368

Agaimy, A., Märkl, B., Kitz, J., Wünsch, P. H., Arnholdt, H., Füzesi, L., ... & Chetty, R. (2010). Peripheral nerve sheath tumors of the gastrointestinal tract: a multicenter study of 58 patients including NF1-associated gastric schwannoma and unusual morphologic variants. Virchows Archiv, 456(4), 411-422.

Antonescu, C. R., Perry, A., & Woodruff, J. M. (2013). Schwannoma (including variants). World Health Organization Classification of Tumours of Soft Tissue and Bone. Fletcher CDM, Bridge JA, Hogendoorn PCW and Mertens F (eds). 4th edition. IARC Press, Lyon, pp170-172.

Carter, J. M., O'hara, C., Dundas, G., Gilchrist, D., Collins, M. S., Eaton, K., ... & Folpe, A. L. (2012). Epithelioid malignant peripheral nerve sheath tumor arising in a schwannoma, in a patient with “neuroblastoma-like” schwannomatosis and a novel germline SMARCB1 mutation. The American journal of surgical pathology, 36(1), 154.

Suchak, R., Luzar, B., Bacchi, C. E., Maguire, B., & Calonje, E. (2010). Cutaneous neuroblastoma‐like schwannoma: a report of two cases, one with a plexiform pattern, and a review of the literature. Journal of cutaneous pathology, 37(9), 997-1001.

Chetty, R. (2011). Reticular and microcystic schwannoma: a distinctive tumor of the gastrointestinal tract. Annals of diagnostic pathology, 15(3), 198-201.

Tang, S. X., Sun, Y. H., Zhou, X. R., & Wang, J. (2014). Bowel mesentery (meso-appendix) microcystic/reticular schwannoma: Case report and literature review. World Journal of Gastroenterology: WJG, 20(5), 1371.

Voltaggio, L., Murray, R., Lasota, J., & Miettinen, M. (2012). Gastric schwannoma: a clinicopathologic study of 51 cases and critical review of the literature. Human pathology, 43(5), 650-659.

Lisle, A., Jokinen, C., & Argenyi, Z. (2011). Cutaneous pseudoglandular schwannoma: a case report of an unusual histopathologic variant. The American Journal of Dermatopathology, 33(5), e63-e65.

Ciau, N., Eisele, D. W., & Zante, A. (2014). Epithelioid schwannoma of the facial nerve masquerading as pleomorphic adenoma: A case report. Diagnostic cytopathology, 42(1), 58-62.

Reviewed and Approved by a member of the DoveMed Editorial Board
First uploaded: March 3, 2017
Last updated: March 3, 2017