Lateral and Dorsal Column Hyperintensity on Magnetic Resonance Imaging in a Patient with Myelopathy Associated with Intrathecal Chemotherapy
A 35-year-old female underwent partial tumor resection and postoperative steroid therapy for a cerebellopontine angle tumor. Three years after treatment, she developed a headache along with vomiting. Cranial MRI revealed a lesion with abnormal intensity in the third ventricle, and transventricular endoscopic biopsy and ventriculostomy were performed. Histological examination revealed the characteristic findings of a diffuse, large B-cell lymphoma. A course of systemic HD-MTX/Ara-C treatment diminished the tumor on brain MRI and improved the clinical symptoms. The patient received an additional 3 courses of HD-MTX/Ara-C and repetitive lumbar intrathecal Ara-C (100 mg) and dexamethasone (4 mg). One month after the first round of intrathecal chemotherapy, the patient complained of bilateral numbness in her lower legs despite normal spinal MRI. She received a repetitive course of intrathecal Ara-C (40 mg) and prednisolone (4 mg) with or without intrathecal MTX (15 mg) for 6 months, along with whole-brain radiotherapy for 1 month. Nine months after the first round of intrathecal chemotherapy, the patient gradually developed an unstable gait. Neurological examination revealed a mild lower-limb weakness and a sensory ataxic gait with a positive Romberg's sign. Pinprick, light touch, vibration sensation, and proprioception were impaired below the level of the Th10 dermatome. Deep tendon reflexes were normal in all limbs, but diminished abdominal reflexes and bilateral extensor planter responses were noted. Macrocytic anemia was present: red blood cells 2.64 × 104 μl, hemoglobin 9.7 g/dl, mean corpuscular volume 112.5 fl, with a reduced thrombocyte count. The results of routine biochemistry, autoantibodies, and a thyroid function test were unremarkable. Her serum vitamin B12 level was in the lower limits of normal [286 pg/ml (normal range 180–914)], and her serum levels of folate and copper were slightly reduced [2.8 ng/ml (normal range >3.1) and 65 mg/dl (normal range 68–128), respectively]. Cerebrospinal fluid (CSF) studies revealed a white blood cell count of 1/μl, a protein level of 24 mg/dl, and increased levels of myelin basic protein (MBP; 502 pg/ml). Nerve conduction velocities and compound muscle action potentials were normal, while somatosensory evoked potentials demonstrated a normal N 20 latent time (19.50 ms) but prolonged P 40 responses (44.1 ms). The patient's spinal T2-WI MRI demonstrated abnormal signal intensity in the bilateral and dorsal columns in the thoracic cord, extending from Th3 to Th10 (fig. ).\nWe performed DTI, DKI, and QSI and calculated each parameter (as described previously [, , ]), in the regions of interest on the dorsal column at Th7–9 and C3–5 of the patient, along with 4 control subjects. The results at Th7–9 of the patient and control subjects (mean ± standard deviation) were as follows: apparent diffusion coefficient (ADC) (10−3 mm2/s): 0.55 and 1.16 ± 0.10; fractional anisotropy (FA): 0.41 and 0.61 ± 0.14; lambda (λ1) (10−3 mm2/s): 0.78 and 2.11 ± 0.19; (λ2 + λ3)/2 (10−3 mm2/s): 0.45 and 0.69 ± 0.19; full width half maximum (μm): 17.45 and 20.32 ± 0.34; mean diffusional kurtosis (MDK): 1.65 and 0.85 ± 0.15. We also obtained MDK at C3–5:1.72, 1.21, 0.78 and 1.00 ± 0.11 (fig. , fig. ).\nThe disease course, hematological findings, and MRI suggested a diagnosis of demyelinating myelopathy due to the combined effect of intrathecal chemotherapy and vitamin and mineral deficiencies. The patient's condition did not deteriorate, but also did not improve despite therapy with intravenous administration of vitamin B12 and folic acid. Seventeen months after the first round of chemotherapy, the patient died of recurrent brain lymphoma. Permission for an autopsy was not granted.