Multifocal infection of mycobacterium other than tuberculosis mimicking a soft tissue tumor of the extremity.

Mycobacterium other than tuberculosis infections rarely develop in healthy individuals, but direct inoculation such as contaminated acupuncture can cause mycobacteriosis even in an immunocompetent host. A 56-year-old woman gradually developed pain on the anterior aspect of the left knee and the distal thigh after hiking without trauma. She received acupuncture for 3 consecutive days on the bilateral knees at the suprapatellar and infrapopliteal areas. After acupuncture, mild localized heat and painful swelling developed around the knees bilaterally. Magnetic resonance imaging (MRI) demonstrated soft tissue masses with a lobulated contour at the prefemoral fat between the suprapatellar pouch and the distal femur and at the proximal tibia behind the knee joint capsule. Fibromatosis, pigmented villonodular synovitis, and soft tissue sarcoma were considered. On pathologic examination, multiple granulomas with lymphoplasmatic infiltration were evident, and acid-fast bacteria staining revealed acid-fast bacilli. A mycobacterial culture confirmed Mycobacterium other than tuberculosis infection, and a polymerase chain reaction-fragment length polymorphism assay identified the isolates as Mycobacterium abscessus. After treatment with appropriate antibiotics, the patient had no evidence of disease and reported no pain during activities of daily living. Acupuncture is growing in prominence in Europe and the United States, and the number of reports on complications increases with its widespread use. Although the risk to an individual patient is difficult to determine, acupuncture may cause serious complications in patients with coagulopathy, heart valve disease, and immune deficiency. In addition, direct inoculation such as contaminated acupuncture can cause mycobacteriosis even in an immunocompetent host.