Peripheral nerve fibromyxoid sarcoma.

Area of Science:

• Oncology
• Pathology
• Surgical Oncology

Background:

• Low-grade fibromyxoid sarcoma (LGFMS) is a rare soft tissue neoplasm often challenging to diagnose due to its subtle presentation.
• LGFMS can be mistaken for other benign or malignant soft tissue tumors, necessitating accurate diagnostic methods.
• Metastatic potential of LGFMS underscores the importance of early and correct identification.

Observation:

• A 49-year-old male presented with a slow-growing thigh mass, initially suspected as schwannoma or perineurioma based on imaging and biopsy.
• The tumor, approximately 5 cm, originated from a saphenous nerve branch, presenting with local discomfort and intermittent numbness.
• Histopathological examination and fluorescence in situ hybridization (FISH) confirmed the diagnosis of LGFMS.

Findings:

• The case represents the first documented instance of LGFMS associated with a peripheral nerve.
• Histopathology revealed characteristic features of fibromyxoid sarcoma, with FISH analysis being crucial for confirmation.
• Radical reexcision achieved clear surgical margins, and the patient experienced a full recovery with no neurological deficits.

Implications:

• This case expands the known spectrum of LGFMS presentation, particularly its association with peripheral nerves.
• It highlights the diagnostic difficulties and the need for advanced techniques like FISH in equivocal cases.
• Successful surgical management and long-term follow-up demonstrate favorable outcomes for LGFMS with appropriate treatment.