gms | German Medical Science

Objectives/Interrogation: An epidermoid cyst is one of the common benign tumor-like conditions in the hand. We report the rare case that an epidermoid cyst induced significant neuralgia of the finger.

Methods: A 56-year-old female presented with significant neuralgia and mass of the right ring finger. 3 years prior to presentation, she had been bitten by a dog. After then, she recognized a growing mass at the site of bitten. 11 days prior to presentation, she recognized the sudden strong pain with her right ring finger as much as jumping up and down. On physical examination, a soft elastic mass was noted on the radial volar aspect of middle phalanx of her ring finger, with strong positive Tinel's sign from the radial volar aspect of metacarpophalangeal to middle phalanx. The Pain visual analog scale (VAS) of the ring finger was 5 / 10. MRI demonstrated a 1.1 × 1.1-cm round, well-circumscribed mass at the middle phalanx of her ring finger with low intensity on T1-weighted and high intensity on T2-weighted. We concluded the significant neuralgia was induced caused by the mass, then we performed surgical excision 6 days after from presentation. Capsule of mass adhered to surrounding tissues and the mass was filled with ash color myxoid substance. The digital nerve was wrapped by the mass and had hypertrophy from the mass to 3cm proximately. The site of nerve hypertrophy was filled with ash color myxoid substance from the mass. After excision of the mass, we squeezed the myxoid substance out from the digital nerve. After then, she had the improvement from the significant neuralgia. Histological examination confirmed the diagnosis of an epidermoid cyst. 1 and a half years following the excision, there was no evidence of recurrence and she remained the improvement that the pain VAS was 0 / 10.

Results and Conclusions: We concluded her significant neuralgia was happened when the myxoid substance of epidermoid cyst strayed into the digital nerve after epidermoid cyst adhered to the nerve.