Case Report: Cutaneous Mycosis Caused by Purpureocillium lilacinum

Purpureocillium lilacinum, widely used as a commercial biocontrol agent for controlling plant-parasitic nematodes, is an emerging opportunistic pathogen in humans and is increasingly reported, especially among immunocompromised patients. We report a classic case of cutaneous mycosis caused by P. lilacinum. A 51-year-old Chinese woman who received tacrolimus and glucocorticoid therapy for 3 years for nephrotic syndrome experienced recurrent papules, pustules, and ulceration on her right ring finger and subcutaneous nodules on her forearm 6 months ago. A lesion biopsy on the right ring finger revealed multiple epithelioid granulomas in the dermis and fat layer containing slender, pigmented fungal hyphae. The fungal culture showed the growth of violet floccose colonies. Lactophenol cotton blue culture stain demonstrated brush-like phialides, with a swollen basal part attached to chains of conidia. Sequencing of the internal transcribed spacer regions of ribosomal DNA, alignment with GenBank, and use of a Basic Local Alignment Search Tool analysis led to the identification of P. lilacinum. Treatment with oral voriconazole was successful.