A Case of Phaeohyphomycosis Caused by Exophiala lecanii-corni
A Case of Phaeohyphomycosis Caused by Exophiala lecanii-corni
复制标题
角部外口菌引起的褐丝菌病一例
作者：
Kyou;Min Ji Kim;S. Chae;Hae Sook Lee;Y. Jang;Seok;Do Won Kim;W. Lee
尊敬的编辑：
暗色丝孢霉病是指皮下和全身真菌感染的特点是暗色分隔菌丝元素1。皮下暗色丝孢真菌病最常见的病原体是让氏外瓶霉。由于流行的免疫抑制治疗和精确的实验室诊断，暗色丝孢真菌病的发病率一直在增加2。据我们所知，在韩国还没有由蜡状外瓶霉引起的皮下暗色丝孢真菌病的报道。
患者男，76岁，右前臂出现边界不清的类风湿性丘疹和斑片，病程18个月。他曾在埃及法老岛的海里游泳。之后，皮肤病变发展并逐渐增大。在旅行之前，他一周前在病变部位有过创伤史。他患有糖尿病（DM）和高脂血症多年。体格检查时，皮损显示在边界不清的紫癜性丘疹上有融合的平顶紫色丘疹（图1A，B）。组织学检查示真皮内肉芽肿由组织细胞和淋巴细胞组成，并可见真菌菌丝和孢子（图2A~D）。用马铃薯葡萄糖琼脂（PDA）与玉米粉琼脂、蛋白胨和吐温80进行真菌培养14天。真菌培养物显示暗褐色至橄榄黑色天鹅绒状菌落（图2 E）。使用乳酚棉蓝染色法进行的显微镜检查揭示了棘状分生孢子梗和单细胞分生孢子簇（图2F）。我们进行了核糖体DNA（rDNA）的内转录间隔区（ITS）的直接测序分析，用于鉴定致病真菌。使用使用基本局部比对搜索工具（BLAST）算法的GenBank国家生物技术信息中心（NCBI）数据库。经GenBank BLAST检索，与已测序的E.（GenBank登录号：{“type”：“entrez-nucleotide”，“attrs”：{“text”：“AY857528.1”，“term_id”：“61676683”，“term_text”：“AY857528.1”}}AY857528.1）。患者口服盐酸特比萘芬250 mg 3个月，然后口服氟康唑150 mg 4个月。治疗后，病变改善，无复发（图1C，D）。
图1
(A)边界不清的紫癜性丘疹上融合的平顶紫色丘疹（B）。(C)治疗后11个月皮肤病变的临床改善，（D）病变的近距离观察。
图2
（A，B）真皮内由组织细胞和淋巴细胞组成的肉芽肿（HE A：×40，B：×400）。（C，D）真皮中真菌菌丝和孢子（C：D-PAS，×400，D：GMS，×400）。(E)深棕色到橄榄色的黑色天鹅绒般的。
1974年Ajello等3首次定义了暗色丝孢霉病。暗色丝孢菌病是指暗色丝孢菌科感染，从皮下真菌病到深部器官感染不等。与着色芽生菌病不同，暗色丝孢菌病显示黑色酵母样细胞、假菌丝样真菌切片、菌丝体或其在组织中的复合体，而不是表皮小体或颗粒4。皮下型常发生在手指、手腕、膝盖和脚踝，这些部位容易受伤和伤口感染5。需与纤维瘤、脂肪瘤、脂肪囊瘤鉴别。在免疫功能低下的患者，如实体器官移植受者，血液肿瘤患者和长期外源性类固醇治疗的患者中，暗色丝孢真菌病正在增加2。
诊断暗色丝孢霉病可通过病史、临床特征、真菌培养、真菌成分显微镜检查、组织病理学检查、聚合酶链反应和rRNA ITS序列分析。我们的病例被诊断为暗色丝孢真菌病使用所有上述方法。
在本案中，E.在韩国尚未报道的lecanii-corni被鉴定出来。外瓶霉属E. castellanii、卡氏E. jeanselmei、黑腹刺蛾E. moniliae、假丝酵母E. pisciphila、E. salmonis和E. spinifera是常见的。本文报告一例罕见的由大肠杆菌引起的暗色丝孢霉病。lecanii-corni。
Dear Editor:
Phaeohyphomycosis refers to subcutaneous and systemic fungal infections characterized by dematiaceous septate mycelial elements1. The most common agent of subcutaneous phaeohyphomycosis is Exophiala jeanselmei. Phaeohyphomycosis has been increasing in frequency because of popular immunosuppressive therapy and precise laboratory diagnosis2. To the best of our knowledge, there has been no report of subcutaneous phaeohyphomycosis due to Exophiala lecanii-corni in Korea.
A 76-year-old man presented with ill-defined pruritic erythematous papules and patches on right forearm for 18 months. He had a history of swimming in the sea of Egyptian pharaoh island. After then, the skin lesion was developed and gradually increased in size. Before the travel, he had a history of trauma at the site of the lesion a week ago. He had undergone diabetes mellitus (DM) and hyperlipidemia for several years. On physical examination, skin lesion showed confluent flat-topped violaceous papules on ill-defined purpuric erythematous patches (Fig. 1A, B). Histopathological examination showed granuloma consisting of histiocytes and lymphocytes, fungal hyphae and spores in dermis (Fig. 2A~D). Fungal culture was done with potato dextrose agar (PDA) with corn meal agar, peptone and tween 80 for 14 days. Fungal culture showed dark brown to olivaceous black colored velvety colony (Fig. 2E). Microscopic examination using lactophenol cotton blue staining method revealed spine-like conidiophores and clusters of single celled conidia (Fig. 2F). We performed a direct sequencing analysis of the internal transcribed spacer (ITS) region of the ribosomal DNA (rDNA) for the identification of causative fungus. The GenBank National Center for Biotechnology Information (NCBI) database using the basic local alignment search tool (BLAST) algorithm was used. The GenBank BLAST search revealed 100% (575/575 bp) homology with a previously sequenced E. lecanii-corni strain (GenBank accession number: {"type":"entrez-nucleotide","attrs":{"text":"AY857528.1","term_id":"61676683","term_text":"AY857528.1"}}AY857528.1). The patient received oral terbinafine HCl 250 mg for 3 months and after then oral fluconazole 150 mg for 4 months. After treatment, the lesion was improved without recurrence (Fig. 1C, D).
Fig. 1
(A) Confluent flat-topped violaceous papules on ill-defined purpuric erythematous patches, (B) close up view of the lesion. (C) Clinical improvement of skin lesion 11 months after treatment, (D) close up view of the lesion.
Fig. 2
(A, B) Granuloma consisting of histiocytes and lymphocytes in dermis (HE A: ×40, B, ×400). (C, D) Fungal hyphae and spores in dermis (C: D-PAS, ×400, D: GMS, ×400). (E) Dark brown to olivaceous black-colored velvety ...
Phaeohyphomycosis, named by Ajello et al.3 in 1974, was first defined. Phaeohyphomycosis refers to Dematiaceae infection, varying from subcutaneous mycosis to deep organ infections. Unlike chromoblastomycosis, phaeohyphomycosis shows black yeast-like cells, pseudomycelium-like fungal sections, mycelia, or their complex in tissues rather than sclerotic bodies or granulation4. The subcutaneous type frequently occurs in the fingers, wrists, knees, and ankles, which can be easily exposed to injury and wound infection5. It needs to be differentiated from fibroma, lipoma, and steatocystoma. Phaeohyphomycosis is increasing in immunocompromised patients such as solid organ transplant recipients, hemato-oncological patients, and patients on chronic exogenous steroid therapy2.
The diagnosis of phaeohyphomycosis can be made by past history, clinical features, fungal culture, microscopic examination of fungal elements, histopathological examination, polymerase chain reaction and rRNA ITS sequence analyses. Our case was diagnosed as phaeohyphomycosis using all of the above methods.
In the present case, E. lecanii-corni, which has not yet been reported in Korea, was identified. Among the Exophiala species, E. castellanii, E. jeanselmei, E. moniliae, E. pisciphila, E. salmonis, and E. spinifera are common. Here we report a rare case of phaeohyphomycosis induced by E. lecanii-corni.