Acta Dermato-Venereologica 99-9CompleteContent | Page 25
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SHORT COMMUNICATION
Interdigital Hyalohyphomycosis Caused by Members of the Fusarium solani Species Complex
Hiromitsu NOGUCHI 1,2 , Tadahiko MATSUMOTO 1,2 , Masataro HIRUMA 2 , Utako KIMURA 2,3 , Takashi YAGUCHI 4 , Miki HIROSE 6 ,
Satoshi FUKUSHIMA 6 and Hironobu IHN 6
Noguchi Dermatology Clinic, 1834-1 Namazu, Kashima-machi, Kamimashiki-gun, Kumamoto 861-3101, 2 Ochanomizu Institute for Medical
Mycology and Allergology, Tokyo, 3 Department of Dermatology, Juntendo University Urayasu Hospital, 4 Division of Bio-resources, Medical
Mycology Research Center, Chiba University, Chiba, and 5 Department of Dermatology and Plastic Surgery, Faculty of Life Sciences, Kumamoto
University, Kumamoto, Japan. E-mail: [email protected]
1
CASE REPORTS
The term “Intertrigo” refers simple intertrigo, bacterial in
tertrigo, candidal intertrigo, interdigital tinea pedis, and in
tertrigo complicated with erythrasma (1). Interdigital fungal
intertrigo is most caused by dermatophytes. In Senegal,
Fusarium species are the second most frequently isolated
fungi after Candida albicans (2). Human-pathogenic mem
bers of the genus Fusarium primarily belong to 8 species
complexes, of which the Fusarium solani species complex
(FSSC) and F. oxysporum species complex account for 60%
and 20% (3). Hyalohyphomycosis and phaeohyphomycosis
were umbrella terms to cover a growing number of opportu
nistic mycoses caused by moulds and yeasts whose septate
mycelial tissue forms were either hyaline (Gr.’huálinos’), or
phaeoid (Gr. ‘phaios’), respectively (4). Here, we provide
the first report of interdigital hyalohyphomycosis caused
by a member of the FSSC in Japan.
Accepted Apr 29, 2019; E-published Apr 29, 2019
Case 1. A 58-year-old, female homemaker with a > 2-year history
of an interdigital lesion visited our clinic in February 2017. She
presented with maceration, erosion, scales, and itching in the left
3 rd interdigital area (Fig. 1a). Direct microscopy revealed irregu
larly distorted septate hyphae (diameter 3–8 µm) and intercalary
and terminal chlamydoconidia (Fig. 1b). Neither Candida species
nor dermatophytes were isolated. Periodic acid-Schiff (PAS)-
stained tissue showed septate hyphae. Hematoxylin and eosin
(H&E) staining revealed basophilic hyphae (Fig. 1c). Plate culture
on Sabouraud’s dextrose agar yielded a white felt-like colony
with pale-yellow colored reverse after 7-day incubation at 25°C
(Fig. 1d). Slide culture on potato dextrose agar yielded abundant
unicellular oval microconidia and septate crescent macroconidia
from verticillate conidiophores after 4-day incubation at 25°C. The
internal transcribed spacer 1 (ITS-1) region of the rRNA gene and
the translation elongation factor 1 alpha (EF-1α) gene sequences
showed 100% (206/206 bp) and 100% (702/702 bp) homologies,
with Fusarium petroliphilum type strain NF 4475 (NRRL 22268
= FRC S-2176) (5) (Mycobank no. MB802539). Based on its
morphological characteristics and the gene analysis results, we
identified the isolate as F. petroliphilum (Q.T. Chen & X.H. Fu)
Geiser, O’Donnell, D.P.G. Short & N. Zhang, which belongs to the
FSSC. The patient was diagnosed with interdigital hyalohyphomy
cosis. Antifungal susceptibility testing was performed according
to the Clinical and Laboratory Standards Institute (CLSI) M38-A2
protocol (6). The minimum inhibitory concentrations (MICs) for
the isolate were: amorolfine, 2 μg/ml; amphotericin B, 2 μg/ml;
efinaconazole, 2 μg/ml; itraconazole, > 16 μg/ml; ketoconazole,
> 16 μg/ml; terbinafine, > 16 μg/ml; and voriconazole, 8 μg/ml.
Routine test results were within the normal ranges. The patient
was treated with 2% ketoconazole cream and her symptoms disap
peared in 4 months. The follow-up culture was negative and she
showed no recurrence, as of December 2018.
Case 2. An 81-year-old, male farmer had noticed an interdigital
lesion in 2014. He applied 1% lanoconazole cream, which had no
effect. In March 2017, maceration and desquamation in the 3 rd and
4 th interdigital lesions were observed (Fig. 1e). Direct microscopy
revealed septate hyphae and chlamydoconidia (Fig. 1f). PAS and
H&E-stained tissue also showed septate hyphae (Fig. 1g). Plate
culture on Sabouraud’s dextrose agar yielded a white floccose co
Fig. 1 (a) Case 1: Maceration, erosion, and scales on the left 3 rd interdigital area. (b) Septate hyphae and intercalary chlamydoconidia (potassium
hydroxide (KOH) with Parker ink, original magnification ×400). (c) Basophilic septate hyphae (hematoxylin and eosin stain, ×400). (d) Plate culture
of Fusarium petroliphilum, a white felt-like colony with pale-yellow-coloured reverse. (e) Case 2: Maceration and desquamation on the left 3 rd and 4 th
interdigital area. (f) Septate hyphae and intercalary chlamydoconidia (Parker ink-KOH, ×400). (g) Septate hyphae in the upper stratum corneum (Periodic
acid-Schiff-stain, ×400). (h) Plate culture of Fusarium keratoplasticum, a white floccose colony with brown-coloured reverse.
This is an open access article under the CC BY-NC license. www.medicaljournals.se/acta
Journal Compilation © 2019 Acta Dermato-Venereologica.
doi: 10.2340/00015555-3202
Acta Derm Venereol 2019; 99: 835–836