Age / Sex : 25 / M

Chief complaint : Left arm weakness after neck lymph node biopsy

What is your diagnosis?


Two weeks later, you can see the final diagonosis with a brief discussion of this case (Please submit only one answer).

Courtesy: 이영준 (Eugene Lee), 분당서울대학교병원 (Seoul National University Bundang Hospital)

Spinal accessory nerve injury

Discussion

<Imaging findings>

CT axial and coronal : enlarged LN at Lt. posterolateral neck (arrowed)

Fat suppressed T2 coronal and enhanced T1 axial : after LN biopsy, increased T2 signal with enhancement noted at Lt. trapezius muscle suggesting acute denervation change (arrowed).

Spinal accessory nerve injury during cervical LN biopsy

 - Incidence: 3-10%

 - Sx: loss of motor function of trapezius m.

 - weakness of the shoulder in abduction, dropping of the shoulder, winging of the

   scapula

 - If untreated, lead to pain and functional deficit in 60-90%

 - Diagnosis: clinical examination + EMG

MRI: can support the diagnosis & provide anatomical information

 - Direct visualization of spinal accessory nerve

    à challenging d/t small diameter (< 1-2 mm)

 - Trapezius muscle atrophy + T2/STIR signal hyperintensity

 - Fatty infiltration in trapezius muscle

 - SCM atrophy +  T2/STIR signal hyperintensity

 - Scar tissue can be visualized along the course of the nerve

  - J Neurosurg Spine 2015;23:518–525

  - Clin Radiol. 2016;71(4):316-20