Non-iatrogenic spinal accessory nerve palsy due to lymph node compression.

Injury to the spinal accessory nerve (SAN) is most commonly of iatrogenic or traumatic origin. The incidence of SAN palsy resulting specifically from lymph node compression is difficult to ascertain, as such cases are typically reported in association with malignancies or following surgical procedures. We report the case of an adolescent who presented with clinical features consistent with SAN palsy, including spontaneous shoulder asymmetry, in the absence of prior trauma or surgical intervention to the cervical region. Surgical exploration revealed compression of the SAN by enlarged lymph nodes. Neurolysis of the nerve was performed, resulting in significant clinical improvement. This case is significant for highlighting a rare cause of SAN palsy, adding to the scarce literature on non-iatrogenic origins of the condition.