J Dermatol 2015 May 13;42(5):518-20. Epub 2015 Mar 13.
Noguchi Dermatology Clinic, Kumamoto, Japan; Department of Immunology, Allergy & Vascular Biology, Kumamoto University, Kumamoto, Japan.
An 18-year-old healthy female student noticed a brown macule measuring 21 mm in diameter on the left palm and visited our clinic concerned about a cancerous mole. Dermoscopic examination revealed a brown, fine-dotted and granule-like structure overlapping an amorphous light brown macule. However, unlike previous cases, analysis of the high dynamic range-converted image revealed the parallel ridge pattern frequently observed in malignant melanomas. Brown mycelia were detected on direct microscopic examination; black colonies were isolated on fungal culture and the fungus was identified as Hortaea werneckii. The lesion was treated with topical ketoconazole cream, and it diminished 1 month later.