Letter to the Editor
Ann Lab Med 2021; 41(2): 247-249
Published online March 1, 2021 https://doi.org/10.3343/alm.2021.41.2.247
Copyright © Korean Journal of Laboratory Medicine.
A Case of Brain Abscess Caused by the Dematiaceous Mold Neoscytalidium dimidiatum in a Korean Man
1Department of Laboratory Medicine, Pusan National University Yangsan Hospital, Yangsan, Korea; 2Department of Internal Medicine, Pusan National University School of Medicine, Busan, Korea; 3Department of Laboratory Medicine, Pusan National University School of Medicine, Busan, Korea; 4Department of Laboratory Medicine, Pusan National University Hospital, Busan, Korea
Correspondence to: Jongyoun Yi, M.D., Ph.D.
Department of Laboratory Medicine, Pusan National University Hospital, 179 Gudeok-ro, Seo-gu, Busan 49241, Korea
Tel: +82-51-240-7417, Fax: +82-51-240-7413
This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/4.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.
This study was conducted for 15 months, from hospitalization to treatment termination and final brain imaging follow-up. A 62-year-old man with progressive dysarthria and general weakness for two weeks was admitted to a tertiary university hospital in March 2017. He had no systemic symptoms, and his underlying medical conditions included liver cirrhosis, past surgery for hepatocellular carcinoma (HCC), and diabetes. Three months earlier, he had visited Thailand. Brain magnetic resonance imaging (MRI) showed a 1.8-cm lesion; a brain abscess or HCC metastasis was suspected. Antibacterial agents were empirically administered. Stereotactic surgery was performed to aspirate the lesion, and pus was drained.
The aspirate was cultured on Sabouraud dextrose agar at 30°C. A mold was isolated and matured quickly within three days; colonies were woolly and dark (Fig. 1A). Hyphae were septate and branched, and numerous rectangular or barrel-shaped arthroconidia were observed, with no empty cells between them (Fig. 1B). Based on these morphological features, the isolate was presumably identified as
Figure 1. Culture of the
Neoscytalidium dimidiatumbrain isolate on Sabouraud dextrose agar. (A) After incubation for three days, the isolate showed white woolly and dark brown to black pigmented colonies filling the agar. (B) Microscopic examination of the N. dimidiatumisolate (× 400). A cellophane tape mount with lactophenol cotton blue stain demonstrated septate hyphae and numerous rectangular arthroconidia (arrow). The arthroconidia and some hyphae were brown.
To genotypically confirm the species, the internal transcribed spacer (ITS) regions were sequenced . The ITS1-5.8S ribosomal DNA-ITS2 sequence (GenBank accession no. MG028648) was analyzed using the International Society for Human and Animal Mycology (ISHAM) ITS database  and showed 99.6% similarity to
Figure 2. Phylogenetic analysis of the isolate from this study and closely related
Neoscytalidiumspp. Botrysphaeria dothideasequences were used as an outgroup. The isolate from this study is marked with ‘Author’ after the species name. (A) Internal transcribed spacer sequences. (B) Sequences of the D1/D2 region of large subunit ribosomal RNA.
After the mold was isolated, the antimicrobial regimen was altered to intravenous amphotericin B (AMB). After a 4-week AMB therapy, the brain lesion showed an approximate 30% decrease in size; however, a new 1.6-cm lesion appeared along the stereotactic aspiration tract. After two additional weeks of AMB therapy, the patient was switched to oral voriconazole and discharged. However, as the lesions remained unchanged according to the MRI conducted after 5-week voriconazole therapy, he was re-admitted and treated again with AMB for another 10 weeks; no further antifungals were subsequently administered. He was treated and followed-up for approximately 15 months in total. Follow-up MRIs showed steady and significant lesion improvement for one year. The dysarthria and general weakness had disappeared, and the brain abscess follow-up was concluded.
Our patient may have acquired the infection while visiting Thailand, and his immunocompromised state possibly contributed to the brain infection caused by this fungus.
We did not analyze antifungal susceptibility because it provides only minimal inhibitory concentrations, which do not correlate with clinical outcomes . Nevertheless, our case indicates that voriconazole was probably ineffective because the lesions did not diminish, whereas AMB provided a gradual but obvious clinical effect. Previous brain abscess cases were fatal espite antifungal therapies [2, 3]. In contrast, our patient was eventually cured after early stereotactic drainage and 5-month antifungal therapy.
This is the first case of a brain infection by
Conceptualization: JY. Data curation: JY, SYJ. Formal analysis: JY. Methodology: JY, SYJ. Investigation: SL, KHK. Writing original draft: SYJ. Writing review & editing: JY, SL, KHK.
CONFLICTS OF INTEREST
No potential conflicts of interest relevant to this study are reported.
This work was supported by a 2-year research grant of Pusan National University.
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