坐骨神経痛で発症しFDG-PET/CTにて特徴的な所見を有したneurolymphomatosisの1例

Solitary Neurolymphomatosis of the Sciatic Nerve Diagnosed by FDG-PET/CT. Case Report

　悪性リンパ腫は稀に末梢神経浸潤を来し，その病態をneurolymphomatosis(NL)という．今回われわれは坐骨神経痛で発症したNLを経験したので報告する．本症例は，腰椎疾患による坐骨神経痛を疑われ，開窓術を施行されたが改善せず，FDG-PET/CTで坐骨神経に沿った病変が判明し，生検で悪性リンパ腫によるNLと診断がついた．多くのNLは悪性リンパ腫の経過中に全身播種病変の一病変として出現するが，稀にNLによる神経症状が悪性リンパ腫の初発症状となる場合があり注意を要する．

　Neurolymphomatosis (NL) is an uncommon syndrome characterized by infiltration of the peripheral nervous system by lymphoma.　We report the case of a 62-year-old man with NL whose initial symptom was sciatica.　He had undergone lumbar fenestration at a hospital specialized in spinal diseases, because lumbar disease was thought to be the cause of the sciatica, but his symptoms worsened, and he was referred to our hospital.　FDG-PET/CT scans revealed two masses with increased FDG uptake, one in the spinal canal and the other in a buttock, and linear FDG accumulation along the sciatic nerve, which connected with the two masses.　Biopsy of the mass in the buttock revealed infiltration of the sciatic nerve by diffuse large B cell lymphoma.　Prior systemic lymphoma has been diagnosed in many cases of NL, but neurological symptoms of NL are sometimes the initial manifestations of lymphoma, as in our case.