Case report: Histological and imaging findings of cervical extensor muscles in a patient with poor outcome of dropped head syndrome after conservative treatment

The pathological conditions in patients with poor natural outcome of dropped head syndrome (DHS) are unclear. A 55-year-old woman demonstrated DHS without any trauma. She was diagnosed with idiopathic neck extensor myopathy DHS and had received conservative treatment for 3 years. However, the symptoms worsened and walking and eating became difficult due to the dropped head. X-rays showed that the C6-7 interspinous space was elongated at cervical flexion. T2-weighted magnetic resonance imaging presented high signal change at the C6-7 inter-spinous space. She underwent surgery, and the pathological findings in the cervical extensor muscles revealed a necrotic tear and angiogenesis at C6-7. Elastic van Gieson stain showed replacement of muscle fibers with collagen tissue at C6-7. Pathological findings of poor outcome DHS after conservative treatment showed severe degeneration in cervical extensor muscles, which could be detected by X-ray and MRI. The irreversible degenerative change in cervical extensor muscles may lead to the poor natural outcome in DHS.