Carpal Tunnel Syndrome Caused by a Lipoma

Abstract

Aims: This report highlights the importance of considering rare local etiologies, such as lipomas, in carpal tunnel syndrome (CTS), even in bilateral presentations where systemic causes are initially presumed, emphasizing the diagnostic value of thorough surgical exploration. Presentation of Case: A 65-year-old woman on hemodialysis presented with bilateral CTS confirmed by electrodiagnostic studies. Following successful left-hand release (attributed to amyloid deposition), a right-hand carpal tunnel release one year later unexpectedly revealed per-operatively a 1 x 1.5 cm lipoma compressing the median nerve. Histopathology confirmed the diagnosis. Post-operatively, she achieved complete symptom resolution on both sides. Discussion: While CTS is frequently idiopathic or associated with systemic conditions like chronic renal failure, rare local causes like space-occupying lesions (SOLs) can compress the median nerve. Although typically suspected in unilateral cases (5.5-12.5% incidence), SOLs can be present in bilateral CTS, complicating pre-operative diagnosis when other systemic etiologies exist, and no imaging has been performed. The lipoma was only discovered due to a systematic, extensive surgical approach, highlighting that symptoms may persist if an underlying local issue is not addressed. Conclusion: Clinicians should consider uncommon local etiologies, including lipomas, in CTS, especially in atypical or unresponsive cases. Thorough surgical exploration is crucial for identifying and treating these rare space-occupying lesions, leading to complete symptom resolution and improved patient outcomes in unusual circumstances.