Fungal pyomyositis is a rare intramuscular infection characterized by swelling and pain at the site of infection. The most common fungal pathogen is Candida spp1. The risk factors include immunodeficiency, previous fungal infection, and broad-spectrum antibiotic exposure2. In addition, steroid therapy may induce subclinical myopathy and subsequent infectious myositis3.
A 48-year-old man presented with intermittent pain and swelling of the lower limbs for 1 month. He was diagnosed with Candida albicans fungemia and received oxacillin and fluconazole for 2 weeks. He had systemic lupus erythematosus (SLE) with secondary Sjögren syndrome complicated by pulmonary hypertension, Child–Pugh class B liver cirrhosis related to hepatitis B infection and alcoholism, and type 2 diabetes mellitus. Previous treatments included hydroxychloroquine, prednisolone 10 mg/day, and methylprednisolone 80 mg/day for 3 days bimonthly because of SLE flares. Physical examination revealed hyperpigmentation, local heat, grade 3 edema of the lower limbs, and bilateral palpable pulsation of the dorsalis pedis. Computed tomography of the lower limbs showed lobulated cystic lesions of varying size in the bilateral flexor hallucis and flexor digitorum muscles (Figure 1). He underwent fasciotomy, and histological examination showed necrotizing inflammation with pseudohyphae and spores within muscle (Figure 2). Tissue culture yielded C. albicans. He underwent debridement and 6-week micafungin treatment, which resulted in complete remission.
Computed tomography shows lobulated cystic lesions (arrows) of varying size in the bilateral flexor hallucis and flexor digitorum.
Photomicrograph shows H&E staining of necrotizing inflammation with pseudohyphae (arrow) and spores within muscle. Magnification ×400.
Chronic lower limb swelling may be seen in patients with SLE; however, if it coexists with pain and other risk factors of pyomyositis, diagnostic imaging could be helpful for the identification of underlying infection.
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