Langerhans Cell Histiocytosis (LCH) is a rare clonal proliferative disorder of dendritic cells predominantly affecting children and commonly involving the skeleton. Cervical spine lesions are uncommon, and minor trauma may mask underlying pathological vertebral collapse, leading to delayed diagnosis. We report a 3-year-old child who presented with acute neck pain and refusal to move the neck following a trivial fall from a sofa. The child was previously healthy, with no fever, weight loss, or constitutional symptoms. Examination revealed a guarded neck posture with marked restriction of cervical motion; neurological function was intact. Radiographs demonstrated collapse of the C3 vertebral body (vertebra plana), and computed tomography confirmed osteolysis without acute fracture fragments. Magnetic resonance imaging showed abnormal marrow signal in C3 with mild prevertebral soft-tissue prominence and no spinal cord compression. Given the disproportionate vertebral collapse relative to the minor trauma, a biopsy was performed. Histopathology revealed proliferation of histiocytic cells with characteristic nuclear features. Immunohistochemistry was strongly positive for CD1a, CD68, Cyclin D1, and S100, confirming LCH, while CD30 and CKAE1/AE3 were negative. The patient was managed with cervical immobilization and initiated on chemotherapy under a multidisciplinary pediatric oncology team. Follow-up with serial radiographs and computed tomography demonstrated progressive vertebral healing and clinical improvement, with restoration of neck mobility and no neurological compromise. Even minor trauma in young children may reveal significant spinal pathology; early recognition of vertebra plana and timely multidisciplinary intervention are critical to prevent long-term morbidity.