Malignant peripheral nerve sheath tumors with t(X;18). A pathologic and molecular genetic study

Area of Science:

• Oncology
• Pathology
• Genetics

Background:

• Spindle cell sarcomas pose diagnostic challenges due to histological similarities.
• Immunohistochemistry and electron microscopy can aid differentiation but may be inconclusive.
• Cytogenetic and molecular genetic analyses offer advanced diagnostic tools.

Purpose of the Study:

• To evaluate the specificity of the chromosomal translocation t(X;18) for diagnosing synovial sarcoma.
• To investigate the presence of t(X;18) in other spindle cell tumors.

Main Methods:

• Reverse transcriptase-polymerase chain reaction (RT-PCR) was used to detect t(X;18).
• RNA was extracted from formalin-fixed, paraffin-embedded tissues of various soft tissue and spindle cell tumors.
• The study cohort included synovial sarcomas and malignant peripheral nerve sheath tumors.

Main Results:

• The t(X;18) translocation was detected in 85% of the studied synovial sarcomas.
• Notably, 75% of the malignant peripheral nerve sheath tumors also exhibited the t(X;18) translocation.
• This indicates a lack of specificity for synovial sarcoma diagnosis.

Conclusions:

• The chromosomal translocation t(X;18) is not a specific diagnostic marker for synovial sarcoma.
• The high prevalence of t(X;18) in malignant peripheral nerve sheath tumors has significant diagnostic implications.
• Rethinking the diagnostic criteria for these tumors is necessary.