An Unusual Case Of Unrelenting Forearm Pain

HISTORY: A 23-year-old right hand dominant female presented with a 9-month history of persistent right forearm pain. Initially, the pain was concentrated in her right wrist and radiated down to her index and middle fingers causing numbness and tingling. Her symptoms were worst at night, and she had some difficulty grasping objects. She was diagnosed with carpal tunnel syndrome and managed conservatively with bracing and NSAIDs. Despite this, her pain worsened and started radiating up into her lateral forearm. An EMG at that time was unremarkable so she was diagnosed with extensor tendinitis and started occupational therapy. She returned to the office stating therapy acutely exacerbated her symptoms and she now had diffuse pain across her right lateral forearm with numbness and tingling in her hand. Her symptoms worsened with activity and improved with rest. She also reported a lump in her forearm that she had not felt previously. PHYSICAL EXAMINATION: On examination, her right forearm had no lesions or obvious deformities. She was diffusely tender to palpation along the dorsal forearm and lateral epicondyle, which worsened with passive pronation and wrist flexion. A mass was palpated in the ulnar aspect with a positive Tinel’s over the mass. She had preserved strength, full range of motion in her wrist and elbow, and could perform thumb opposition. She endorsed pain and hyperesthesia in the radial sensory distribution over the dorsum of the right hand, but normal sensation in the median and ulnar distributions. Her right hand was well-perfused with 2+ radial pulse. DIFFERENTIAL DIAGNOSIS: 1. Radial tunnel syndrome 2. Extensor tendinitis with co-occurring carpal tunnel syndrome 3. Neoplasm TESTS AND RESULTS: Right forearm MRI showed an ovoid enhancing lesion in the ulnar aspect of the mid forearm, but no acute osseous abnormalities. FINAL WORKING DIAGNOSIS: Neurogenic tumor of right forearm TREATMENT AND OUTCOMES: Patient underwent surgical removal of a round, firm lesion, which was confirmed as a schwannoma on pathology. On 2-week follow up, her forearm and wrist pain had improved significantly. She had mild lingering pain over the dorsum of her hand, but stated it was improving. She had some limitations in thumb range of motion for which she started therapy but has returned to work and all activities without restrictions.