CASE REPORT

A Case of Chromoblastomycosis Caused by Fonsecaeapedrosoi Successfully Treated by Oral ItraconazoleTogether with Terbinafine

Xu-Cheng Shen . Xiang-Nong Dai . Zhi-Min Xie . Ping Li .

Sha Lu . Jia-Hao Li . Yi Zhang . Xing-Dong Ye

Received: December 16, 2019 / Published online: February 21, 2020� The Author(s) 2020

ABSTRACT

Patients with chromoblastomycosis (CBM)usually have a history of local skin damagerelated to outdoor activities, mainly manifestedas chronic refractory proliferative pathologicchanges. We report a case of a 56-year-old manwith CBM, identified as Fonsecaea pedrosoiinfection by fungal culture and gene sequenc-ing. This patient was successfully treated with aregimen of oral itraconazole (ITZ) and terbina-fine lasting 7 months. Through in vitro drugsensitivity tests, minimum inhibitory concen-trations of amphotericin, ITZ, and terbinafinewere 1 lg/ml, 0.25 lg/ml, and 1 lg/ml,

respectively. In this case, terbinafine was foundto be more effective than ITZ.

Keywords: Chromoblastomycosis; Fonsecaeapedrosoi; Fungal gene sequencing; In vitroantifungal susceptibility; Terbinafine

Key Summary Points

A case of a 56-year-old man was reportedwith chromoblastomycosis at his leftankle for more than 1 year, identified as F.pedrosoi infection by fungal culture andgene sequencing

The minimum inhibitory concentrations(MIC) of drug sensitivity testing in vitrowere amphotericin 1 lg/ml, itraconazole(ITZ) 0.25 lg/ml, and terbinafine 1 lg/ml,and they were equally effective against thewild F. pedrosoi strain. The patient wassuccessfully treated with oral ITZ togetherwith terbinafine

Though the MIC of ITZ was lower thanthat of the other two antifungal agents,we concluded that the drug sensitivity testresult of ITZ was not predictive of clinicalresults. ITZ seems to have had less of ananalgesic effect than terbinafine

Enhanced Digital Features To view enhanced digitalfeatures for this article go to https://doi.org/10.6084/m9.figshare.11744127.

X.-C. Shen � X.-N. Dai � Z.-M. Xie � P. Li �X.-D. Ye (&)Department of Dermatology, Dermatology Instituteof Guangzhou Medical University, GuangzhouMedical University, Guangzhou 510182, Chinae-mail: yxingdong@qq.com

X.-N. Dai � Y. Zhang � X.-D. YeDepartment of Dermatology, Guangzhou Instituteof Dermatology, Guangzhou 510095, China

S. Lu � J.-H. LiDepartment of Dermatology, Sun Yat-sen MemorialHospital, Sun Yat-sen University, Guangzhou510120, China

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https://doi.org/10.1007/s13555-020-00358-y

INTRODUCTION

Chromoblastomycosis (CBM), also known aschromomycosis, is a chronic fungal infection ofthe skin caused by pathogenic fungi [1]. Themost common etiologic agents are Cladophialo-phora carrionii and Fonsecaea pedrosoi. C. carrioniiis found in drier climates, whereas F. pedrosoi isseen in humid forests [2]. CMB is one of themost common implantation fungal infections,and it occurs worldwide, particularly in tropicaland subtropical regions, such as those ofsouthern China [1–3]. In China, CBM was firstdescribed by Yew in 1951 [4] and by otherauthors afterward [3, 5, 6]. CBM is difficult tocure, especially in patients with moderate tosevere cases. Here, we report a case of mild CBMof the plaque type caused by F. pedrosoi in Chinathat was successfully treated with oral itra-conazole (ITZ) and terbinafine.

CASE PRESENTATION

Case History

A 56-year-old man from Hainan, China, visitedour clinic with a progressively growing, painfulred plaque at the inner side of his left anklefollowing an injury caused by a dust-covereddry root. He had been injured 18 months earlierduring his work as a root carver in HainanProvince, a tropical region in southern China.He had sought treatment at more than onehospital, but the plaque did not improve andgradually enlarged, and its central area began toulcerate and exudate, with occasional purulentdischarge. The patient was otherwise healthy.Medical examination showed the patient’s vitalsigns and nervous system were normal. Therewas an elliptic red plaque on his left ankle, andhe felt pain when it was squeezed. The relatedlymph nodes were not swollen. Informed con-sent was obtained from the patient for publi-cation of the article.

Fungal Culture and Identification

A small piece of tissue was cut from the plaqueat the left ankle for mycologic culture andhistopathologic examination. Before treatment,this piece was divided into four equal parts andinoculated in four tubes on chloramphenicol-containing Sabouraud glucose agar (SGA) withor without 0.25% cycloheximide at 26 �C or37 �C respectively. Two weeks later, colonieswith the same morphology were observed in allfour tubes, and the best colony growth wasobserved in the tube of SGA medium with0.25% cycloheximide at 26 �C. The base of thecolony was dark brown and black, the centralpart was gray and fluffy, and the fluffy surfacewas wrinkled and radially distributed (Fig. 1b).Cladosporium-type spore formation wasobserved after the smear (Fig. 1c).

Histopathologic Examination

Histopathologic examination revealed mildhyperplasia of the epidermis, collagen hyper-plasia in the dermis, and superficial capillaryhyperplasia. Inflammatory cells were mainlylymphocytes, infiltrating around the bloodvessels, and some lymphocytes had invaded thevessel wall (Fig. 1d). No sclerotic bodies wereobserved with periodic acid-Schiff (PAS)staining.

Molecular Type Identification

A yeast genomic DNA isolation kit (TiangenBiochemical Technology Co., Ltd.) was used toextract and purify DNA according to the man-ufacturer’s instructions at a laboratory in theWuhan branch of Huada Biotech Corp., Shen-zhen. A 637-bp fragment of the 18S rRNA regionwas amplified with the specific primer pair ITS1/ITS4: ITS1, 50-TCCGTAGGTGAACCTGCGG-30;ITS4, 50-TCCTCCGCTTATTGATATGC-30. AllPCR steps were carried out according to stan-dard protocol. PCR products were elec-trophoresed on a 0.1% agarose gel (Fig. 2a), andsequences were analyzed by comparison to theF. pedrosoi KMU3817 strain (NCBI Accession No.

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AB117982.1) with Bioedit software (Carlsbad,CA, USA) (Fig. 2b, partial sequence).

In Vitro Antifungal Susceptibility

The wild F. pedrosoi strain was cultured inpotato dextrose agar medium for the purpose oftesting antifungal susceptibility using the dilu-ted micro-broth culture method, and the strainATCC-22019 of Candida parapsilosis was used forquality control. The minimum inhibitory

concentrations (MIC) of the tested drugs wereobtained as follows: amphotericin 1 lg/ml,itraconazole (ITZ) 0.25 lg/ml, and terbinafine1 lg/ml.

Therapeutic Intervention and Outcomes

The patient was initially given ITZ 200 mg oncedaily, and plaques were significantly lessinflamed after 2 weeks of treatment (Fig. 3a, b).ITZ was then administrated for the following

Fig. 1 Data on clinical, mycologic cultures, andhistopathologic examination. a An elliptical red plaqueapproximately 2.5 cm 9 4.0 cm in size with a marginalbulge was visible. b Black, velvety colonies with raisedcenters appeared after 4 weeks of incubation at 26 �Cincubator on chloramphenicol-containing SGA with the

presence of 0.25% cycloheximide. c Characteristic conidiaor hyphae of F. pedrosoi under a microscope. dHistopatho-logic examination showing mixed granulomatous inflam-mation (9 100), but no micro-abscesses or sclerotic bodieswere observed with periodic acid Schiff (PAS) staining

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Fig. 2 Data on 1% agarose gel electrophoresis and blastsequence. a PCR amplification of 637-bp-length targetfragment was carried out in a 30 ll reaction volume with0.2 lM concentration of each dNTP, 0.1 lM of eachprimer, 10 ng of template DNA, and 1.25 U of Taqpolymerase with 5 min at 95 �C, followed by 35 cycles at

95 �C for 30 s, 55 �C for 30 s, and 72 �C for 60 s with afinal extension at 72 �C for 10 min, 1% agarose gelelectrophoresis. b Target sample 18S rRNA sequence blastwith F. pedrosoi KMU3817 strain (NCBI Accession No.AB117982.1)

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6 weeks. By the end of the 8th week, the plaquewas basically stable, though there was noimprovement in pain, and the patient discon-tinued ITZ himself. At the 12th week, the lesionhad gotten worse, and the plaque produced pus-like purulent secretions when squeezed(Fig. 3c). The treatment scheme was modifiedwith a combination of terbinafine 250 mg oncea day and doxycycline 100 mg twice daily at the13th and 14th weeks; the surface purulent dis-charge improved, and the size of the plaquedecreased (Fig. 3d). The terbinafine dose was

increased from 250 mg to 500 mg daily at the15th week and afterward, and the lesionimproved continually and finally healed, leav-ing a pale red scar after 7 months of treatmentwithout side effects (Fig. 3e–i).

DISCUSSION

CBM actually includes two diseases: chro-moblastomycosis, which is caused by a funguswith brown, thick-walled spores in the tissue,

Fig. 3 Group diagram for changes in skin lesions. Anelliptical red plaque with marginal bulge surrounded redzone and clustered with necrotic tissue as black dots on thesurface of lesions (a, in white arrow). After 8 weeks oftreatment with ITZ, the red plaque inflammation hadimproved significantly (b). At the 12th week, pus-likepurulent secretions appeared at the plaque surface afterITZ had been discontinued since 8th week (red arrows)

(c). The plaque had subsided and was flattened, thepurulent secretions disappeared, and the lesion showedimprovement. The granulation had disappeared, leavingpale red pigmentation when shifted to terbinafine 250 mgto 500 mg daily treatment at the 13th week and afterward(d–i), and it had crusted over because of applying asolution of poinsettia (a corrosive herbal medicine) toaddress itching (h–i)

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and phaeohyphomycosis, which is caused by afungus with brown, separated hyphae in thetissue [2, 7]. CBM is mainly caused by five spe-cies of dark-colored spore fungi belonging tofour genera, namely C. carrionii, Fonsecea com-pacta, F. pedrosioi, Phialophorae verrucosa, andRhinocladiella cerophilim [1], with the mostcommon etiologic agents being F. pedrosoi andC. carrionii. F. pedrosoi is most commonly foundin humid forests [2]. Dark spore fungi are foundin wet and decaying trees, other plants, and soil,so skin lesions are more common in the handsand feet [7]. The muriform nature of the cells isthe main diagnostic feature. These cells may beclustered with necrotic tissue as black dots vis-ible on the surface of lesions. The correct diag-nosis is usually made with characteristichistopathology and may be confirmed via cul-ture [2]. In this case, pathologic examinationrevealed either no characteristic sclerotic bodiessuggestive of fungal infections, which may havebeen due to sectioning, or at most a few spores.Notably, ITZ was effective following drug sen-sitivity testing, but terbinafine was required asITZ could neither cure nor provide anti-in-flammatory and analgesic effects, indicatingthat drug susceptibility testing is not alwayspredictive of clinical results.

CBM should be differentiated from verrucousskin tuberculosis, syphilis, disseminated blasto-mycosis (affected skin), primary cutaneoussporozoites, sporotrichosis, and squamous cellcarcinoma. CBM can be divided into five mor-phologic types: nodular, plaque, tumor, verru-ciform, and cicatricial [1, 2]. For our patient, adiagnosis of the CBM-plaque type was made,though PAS was negative for brown thick-wal-led spores in the histopathologic examination.

CBM lesions are often unresponsive to manyantifungal and surgical procedures; a completeclinical response is defined as definitive resolu-tion of all lesions [1]. In early stage localizedlesions, excision is recommended. Efficacioustreatments include physical therapies such ascryotherapy (for lesions under 15 cm in diame-ter) [1], photodynamic therapy, and laser treat-ment [8, 9]. Topical injection of dextran can beused to treat refractory cases with severe skinlesions [10], in addition to systemic antifungaltherapy including terbinafine, ITZ, and

amphotericin B [11]. ITZ capsules show clini-cally significant activity against most CBMagents, although it is more effective against C.carrionii than against F. pedrosoi [12, 13].According to the in vitro drug sensitivity test,amphotericin, ITZ, and terbinafine were equallyeffective against F. pedrosoi, and ITZ was moreeffective than other agents. Initially, the patientdescribed here was given 200 mg ITZ once dailyfor 8 weeks, but because it did not alleviate hispain even though the plaque flattened signifi-cantly, he discontinued ITZ himself. We thentreated him with a terbinafine dose of250–500 mg once daily to achieve successfultreatment. Antifungal susceptibility testingshowed the MIC of ITZ to be lower than that ofterbinafine, though terbinafine was able toreduce the size of the skin lesions withoutnotable adverse reactions during the treatment.

CONCLUSIONS

We concluded from drug susceptibility testingthat amphotericin, ITZ, and terbinafine areequally effective against F. pedrosoi in vitro, andthe MIC of ITZ was lower than that of the othertwo agents. However, the drug sensitivity test ofITZ was not predictive of clinical results. ITZseems to have had less of an analgesic effectthan terbinafine.

ACKNOWLEDGEMENTS

We thank the patient for his participation andwe extend our regard to the Guangzhou Insti-tute of Dermatology Research EthicsCommittee.

Funding. No funding or sponsorship wasreceived for this study, and The Rapid ServiceFee was funded by the authors.

Authorship. All named authors meet theInternational Committee of Medical JournalEditors (ICMJE) criteria for authorship for thisarticle, take responsibility for the integrity ofthe work as a whole, and have given theirapproval for this version to be published.

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Authorship Contributions. Xu-Cheng Shenand Xiang-Nong Dai are co-first authors.

Disclosures. Xu-Cheng Shen, Xiang-NongDai, Zhi-Min Xie, Ping Li, Sha Lu, Jia-Hao Li, YiZhang, and Xing-Dong Ye have nothing todisclose.

Compliance with Ethics Guidelines. In-formed consent was obtained from the patientfor publication of the article.

Open Access. This article is licensed under aCreative Commons Attribution-NonCommer-cial 4.0 International License, which permits anynon-commercial use, sharing, adaptation, dis-tribution and reproduction in any medium orformat, as long as you give appropriate credit tothe original author(s) and the source, provide alink to the Creative Commons licence, andindicate if changes were made. The images orother third party material in this article areincluded in the article’s Creative Commonslicence, unless indicated otherwise in a creditline to thematerial. If material is not included inthe article’s Creative Commons licence and yourintended use is not permitted by statutory regu-lationor exceeds thepermitteduse, youwill needto obtain permission directly from the copyrightholder. To view a copy of this licence, visit http://creativecommons.org/licenses/by-nc/4.0/.

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