原発性免疫不全症患者に合併したMycobacterium genavense感染による多発脳病変の1例

Multiple Infectious Intracranial Lesions of Mycobacterium genavense in an Immunocompromised Patient

はじめに

　非結核性抗酸菌（nontuberculous mycobacteria：NTM）の感染はacquired immune deficiency syndrome（AIDS）や臓器移植後など免疫不全患者の重要な合併疾患であり，近年それらの患者増加に伴い注目されてきている。NTM感染の多くは播種性感染で胸腹部を中心に病変を形成することが多い^1，2）。頭蓋内病変は比較的稀であり，これまで多くの報告があるとはいいがたい^3－9）。今回，われわれはNTMの中でも稀なMycobacterium genavense（M. genavense）感染による多発脳病変の生検例を経験した。本疾患の臨床経過や画像所見に文献的考察を加えて報告する。

Abstract

　Nontuberculous mycobacteria rarely infect the central nervous system.　Recently, Mycobacterium genavense, nontuberculous mycobacterium (NTM), has been identified as a significant pathogen in patients.　In this report, we describe multiple intracranial lesions caused by M. genavense in an immunocompromised host.　A 50-year-old man presented with dysarthria, aphasia, and right hemiparesis.　He had a primary immunodeficiency and a M. genavense infection in the thoracic and abdominal lymph nodes.　Magnetic resonance imaging revealed multiple intracranial masses in the subcortical regions with extensive perifocal edema.　Laboratory investigations and cultures of cerebrospinal fluid provided no evidence of disseminated infection.　We obtained a biopsy sample via a small craniotomy using neuronavigation, and NTM infection was confirmed on analysis of the specimen.　He was treated with antimycobacterial agents, and the clinical symptoms and radiological findings improved.　Although a surgical procedure bears the potential risk of infection, especially in an immunocompromised patient, a brain biopsy was necessary for definitive diagnosis in this case and it aided in the administration of appropriate treatment.

(Received: June 11,2010,Accepted: August 9,2010)