Spinal pencil-shaped softening after intramedullary hemorrhage due to thoracic intramedullary cavernous malformation: illustrative case

BACKGROUND: Spinal pencil-shaped softening after intramedullary hemorrhage of a thoracic intramedullary cavernous malformation (ICM) is an extremely rare phenomenon. OBSERVATIONS: A 76-year-old woman presented to the authors' hospital with back pain, sensory disturbance in the left leg, and gait disturbance. MRI revealed an intramedullary hemorrhage at T2-3, predominantly on the left side, spreading down to the T4 body level on T2-weighted imaging. This seemed to have the same appearance as pencil-shaped softening. Three days after admission, paralysis and bladder/rectal dysfunction were observed, and by day 10, complete paralysis had occurred. Repeated MRI demonstrated that the pencil-shaped softening had spread from C7 to T6. On day 39, the abnormal lesion at T2-3 was completely resected and diagnosed as a cavernous malformation based on pathological findings. The patient's neurological symptoms did not improve after sufficient rehabilitation. LESSONS: Pencil-shaped softening of the spinal cord, which indicates high intramedullary pressure, due to hemorrhage of a spinal ICM is a rare phenomenon. Intervention may be attempted in the acute phase before neurological deterioration occurs if this phenomenon is observed in a timely manner. https://thejns.org/doi/10.3171/CASE25927.