A 4-year-old girl was diagnosed with B-precursor ALL with the involvement of kidneys and pancreas in November, 2004. Treatment was initiated according to the Pediatric Oncology Group (POG) protocol 9006
12). On April 12, 2006, the patient was admitted to pediatric clinic with a complaint of intermittent fever for 3 days. On April 19, 2006, 7 days after the admission, the patient developed a gait disturbance. Neurological examination revealed paraparesis of grade 3 on Medical Research Council (MRC) Muscle Strength Grading Scale
1) with increased deep tendon reflex in both ankles, knee jerks, and bilateral positive babinski sign, but her senses were intact. Laboratory findings were inconclusive in blood cell counts, serum and urine. Cerebrospinal fluid (CSF) findings were as follows: elevation of protein (243.3mg/dL), and decrease of glucose (44mg/dL). Neither microorganisms nor malignant lymphocytes were detected in the CSF. The condition was suspected to be an acute inflammatory demyelinating polyneuropathy and was treated with intravenous immunoglobulin (400 mg/kg/day) for 5 days. However, her paraparesis was aggravated to grade 1 on MRC Muscle Strength Grading Scale from April 26, 2006, 14 days after the admission, and spinal MRI was performed. T2 weighted MRI demonstrated heterogeneous high signal intensity infiltration on T4 vertebral body and subligamental spreading soft tissue mass on T3-5 epidural space from T4 posterior vertebral body, causing spinal cord compression (
Fig. 1). On April 27, 2006, laminectomy of T3, 4 with open biopsy were performed. The epidural mass was encircling the spinal cord mainly on ventral surface and was slightly grey to yellow, solid and compact nature. The mass was almost completely removed. A histopathologic examination showed an angiocentric distribution of polymorphous lymphoid infiltrate, with extensive necrosis. Immunohistoche mical staining for CD3 and CD20 showed the predominance of mature T cells and atypical B cells (
Fig. 2). In situ hybridization revealed positivity for Epstein-Barr virus (EBV) encoded RNA in a few lymphocytes, confirming the diagnosis of grade II LYG. One-week post-operative neurologic examination showed paraparesis grade 3 on MRC scale, and bare independent walking but as she still had gait impairment, she received rehabilitation. After four weeks of the surgery, she restored her normal state and could walk quite well. At that time, there were no pulmonary lesions, so we suspected the spinal lesion as the primary involvement site. Two weeks after, chest and abdomen CT revealed multiple low density nodular mass on the liver and the lower lobe of the left lung. Histopathologically, lesions were not blastic in appearance and in immunophenotype, and the lesions were negative for CD10, Tdt, and CD22, so we ruled out the relapse of ALL. She was treated with rituximab (275mg/m
2/day, 4 times per week) for 4 weeks and intravenous high dose methylprednisolone (30mg/kg per day for 3 days, 20mg/kg per day for 2 days and 10mg/kg per day for 2 days). Chest and abdomen CT showed marked improvement of the lesions 3 months after the treatment compared with the lesions in the images obtained before the treatment. She was discharged from our hospital in July 2006. A follow-up MRI study performed 4 months after the operation documented no evidence of residual mass or recurrence (
Fig. 3). Chest and abdomen CT performed 1 year after the operation showed no demonstrable focal lesion in lung field and mediastinum and unremarkable abdominal organs. Her weakness improved and she was able to walk independently and had no gait impairment. But unfortunately we failed to take additional follow-up of MRI for the patient, as she was terrified to take MRI and full sedation was not possible. Moreover the parents of the patient did not agree with the idea of taking MRI one more time because she was in good state at that time. To date, her condition remained stable without recurrence.