TouchDERMATOLOGY coverage from EADV2025:
Following his e-poster presentation “Molecular Identification of Fonsecaea pedrosoi in Chromoblastomycosis: Insights from Paraffin-Embedded Human Skin Biopsies and Clinicopathology” at the European Academy of Dermatology and Venereology (EADV) Congress in Paris (17–20 September 2025), we spoke with Assistant Professor Teerapong Rattananukrom (Division of Dermatology, Department of Medicine, Faculty of Medicine Ramathibodi Hospital, Mahidol University, Bangkok, Thailand) about the clinical presentation and challenges of managing chromoblastomycosis, and his research on improving species-level identification of Fonsecaea pedrosoi using molecular techniques.
Q. What are the typical clinical features and progression of skin lesions seen in patients with chromoblastomycosis?
Chromoblastomycosis is a subcutaneous mycosis that causes fungal infection of the dermis and subcutaneous tissue, typically in immunocompromised or long-term exposed individuals. Clinically, it usually presents as small papules or warty nodules at the site of trauma, which may gradually progress into larger, cauliflower-like masses or verrucous plaques. Characteristic black dots may be visible on the surface of the lesions, representing trans-epidermal elimination of fungal elements as part of the host immune response. Without treatment, the disease can lead to disfigurement and, in rare cases, malignant transformation into squamous cell carcinoma.
Q. Why is chromoblastomycosis often challenging to treat?
There are several factors that affect the treatment outcomes of chromoblastomycosis. Firstly, the thick walls of the muriform cells (the characteristic fungal forms seen in chromoblastomycosis) are highly resistant to the host’s immune clearance and to antifungal treatment penetration.
Secondly, the chronic inflammatory environment leads to skin fibrosis, which makes drug delivery and penetration into the lesions even more difficult.
The early detection and initiation of antifungal therapy is therefore essential. Treating the infection in its early stages can shorten the duration of antifungal therapy and help prevent these complications.
Q. Could you give a brief overview of your presentation on identifying Fonsecaea pedrosoi in chromoblastomycosis?
This year, my e-poster at the EADV Congress focused on a method to identify Fonsecaea pedrosoi directly from formalin-fixed, paraffin-embedded (FFPE) human skin biopsy samples. Traditional fungal cultures often fail to identify the causative agents, and in some regions, PCR cannot be performed directly from fresh tissue. Therefore, the use of FFPE tissue offers a valuable alternative for identifying the pathogen responsible for chromoblastomycosis.
Fonsecaea pedrosoi is a common causative agent of chromoblastomycosis, particularly in Latin America and Central America. I conducted this study in collaboration with my mentor, Prof.Roberto Arenas, Mycology Section, Hospital General “Dr. Manuel Gea González”, Mexico City, Mexico. The research focused on cases of chromoblastomycosis of Mexican origin, using PCR and sequencing of the 18S–ITS1–5.8S–ITS2–28S rDNA region from FFPE skin biopsies to achieve accurate species-level identification.
In our samples (n = 9), Fonsecaea pedrosoi was identified with 100% homology in all cases, demonstrating the reliability of molecular identification using FFPE samples. This approach not only enables more precise diagnosis but also enhances understanding of local epidemiology and supports more effective treatment strategies.
Read the full article: Hernandez-Castro R, Arenas R, Esquivel-Pinto I, Rattananukrom T. Molecular identification of Fonsecaea pedrosoi in chromoblastomycosis: Insights from paraffin-embedded human skin biopsies and clinicopathology. Med Mycol. 2025 Jul 2;63(7):myaf055. doi: 10.1093/mmy/myaf055.
Disclosures: T Rattananukrom has nothing to disclose in relation to this interview.
This content has been developed independently by Touch Medical Media for touchDERMATOLOGY. It is not affiliated with the European Academy of Dermatology and Venereology (EADV). Views expressed are the speaker’s own and do not necessarily reflect the views of Touch Medical Media.
Cite: Rattananukrom T. Improving diagnosis of chromoblastomycosis: Molecular identification of Fonsecaea pedrosoi from paraffin-embedded skin biopsies. TouchDERMATOLOGY. October 31, 2025
Editors: Gina Furnival.
More content in infectious diseases.
Related content
Virtual training model and app accelerates efforts to tackle skin neglected tropical diseases
What’s new in diagnosing and treating onychomycosis
Insights from CAMP-1 and CAMP-2 studies on cantharidin solutions (0.7%) in molluscum contagiosum
