Cutaneous mucormycosis caused by Mucor irregularis in a patient with CARD9 deficiency

Extract

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Conflicts of interest: none to declare.

Dear Editor, Cutaneous mucormycosis is a rare disease caused by opportunistic fungi, which usually affects patients with immunosuppression. Mucor irregularis is a distinctive pathogenic fungus in the order Mucorales, which prevails in China. Unlike in common mucormycosis, it mostly involves nonimmunocompromised individuals.1 Gene deficiency of patients with cutaneous mucormycosis has never been reported to our knowledge. We report the first case of cutaneous mucormycosis caused by M. irregularis with CARD9 deficiency.

A 46‐year‐old otherwise healthy woman presented with a gradually enlarging plaque on the left frontal area for 5 months (Fig. 1a). She noted a red papule appearing 5 months earlier, with occasional itch and without pain and discomfort of her eyes and head. She had undergone a resection of the skin lesion 4 months earlier with a diagnosis of eyelid tumour in the local hospital. However, the skin lesion relapsed and enlarged rapidly after the surgery. She worked as a farmer and had no clear trauma history. Dermatological examination revealed a 4 × 6‐cm well‐demarcated erythematous mass on her left frontal and periorbital area, with a 2‐cm scar on the upside of the eyebrow. Histopathological examination showed infiltration with multiple inflammatory cells (histocytes, neutrophils and multinucleated giant cells) with thin, short hyphae in the dermis (Fig. 1b). Microscopic examination of a direct scraping showed branched nonseptate hyphae (Fig. 1c), and tissue culture showed a yellowish white cotton‐like colony (Fig. 1d). The internal transcribed spacer regions of ribosomal DNA of the strain were sequenced. The sequence showed homology with type strain F3‐3‐8 in GenBank (KX349458) and was confirmed as M. irregularis.