Multiple Schwannomas of the Lower Extremity

Area of Science:

• Oncology
• Genetics
• Pathology

Background:

• Schwannomas are nerve sheath tumors, typically benign.
• Multiple schwannomas can indicate genetic syndromes like neurofibromatosis type 2 (NF2) or schwannomatosis.
• INI1 (SMARCB1) gene alterations are linked to tumor suppression and various neoplasms.

Observation:

• A 72-year-old male presented with multiple subcutaneous nodules on the left foot, ankle, and a history of groin masses.
• Magnetic resonance imaging revealed high-T2-weighted signal intensity masses in the plantar heel and ankle.
• Surgical excision and subsequent pathological analysis confirmed the masses as schwannomas.

Findings:

• Immunohistochemistry demonstrated a mosaic pattern of INI1 expression in the tumor tissue.
• The clinical presentation and pathological findings were consistent with a diagnosis of multiple schwannomas.
• Given the patient's history, neurofibromatosis type 2 was considered the more probable underlying diagnosis.

Implications:

• This case highlights the importance of considering genetic syndromes in patients with multiple schwannomas.
• INI1 expression patterns can provide clues for diagnosis and potential genetic counseling.
• Accurate diagnosis is crucial for appropriate patient management and prognosis, especially in suspected NF2 cases.