[1] Mito Saiseikai Gen Hosp, Dept Pathol, Mito, Ibaraki 3114198, Japan
[2] Mito Saiseikai Gen Hosp, Dept Neurosurg, Mito, Ibaraki 3114198, Japan
[3] Fukushima Rosai Hosp, Dept Pathol, Iwaki, Fukushima, Japan
[4] Gunma Univ, Sch Med, Dept Pathol, Maebashi, Gumma 371, Japan
[5] Oka Orthopaed Clin, Oyama, Tochigi, Japan
[6] Nagoya Univ, Sch Med, Dept Pathol, Nagoya, Aichi 466, Japan