Berg Jena C, Hamacher Kirsten L, Roberts Glenn D
Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN 55905, USA.
J Cutan Pathol. 2007 May;34(5):431-4. doi: 10.1111/j.1600-0560.2006.00628.x.
A 65-year-old woman with a history of liver and kidney transplantation presented with a pruritic and tender rash of 2-year duration on her left knee.
The patient had a physical examination, and multiple skin biopsies were performed.
Examination showed a cluster of dome-shaped, violaceous papules. A skin biopsy specimen showed multiple granules containing basophilic material within the superficial to mid dermis. The grains were embedded in an eosinophilic substance and surrounded by granulomatous inflammation. A Gomori methenamine silver stain showed abundant septate hyphae, and cultures grew colonies of Microsporum canis. A diagnosis of dermatophytic granuloma, or pseudomycetoma, was made. After considering the patient's immune status, a prolonged course of fluconazole was initiated.
Microsporum canis, a frequently encountered zoophilic dermatophyte associated with tinea capitis and tinea corporis, is rarely associated with a mycetoma-like presentation, grain formation, or systemic infection. The medical literature describes only six cases of M. canis causing mycetoma-like formations in immunocompromised and immunocompetent patients. This case report describes an unusual presentation of a common dermatophyte infection, and the literature review summarizes the importance of recognizing atypical presentations of dermatophyte infections. Such infections may warrant more aggressive treatment in immunocompromised patients.
一名65岁有肝肾移植史的女性，左膝出现持续2年的瘙痒性皮疹且伴有压痛。
对该患者进行了体格检查，并进行了多次皮肤活检。
检查发现一簇圆顶状、紫罗兰色丘疹。皮肤活检标本显示在真皮浅层至中层有多个含有嗜碱性物质的颗粒。这些颗粒嵌入嗜酸性物质中，并被肉芽肿性炎症包围。Gomori六胺银染色显示大量分隔菌丝，培养长出犬小孢子菌菌落。诊断为皮肤癣菌肉芽肿，即假真菌瘤。考虑患者的免疫状态后，开始使用延长疗程的氟康唑。
犬小孢子菌是一种常见的亲动物性皮肤癣菌，与头癣和体癣相关，很少与真菌瘤样表现、颗粒形成或全身感染有关。医学文献仅描述了6例犬小孢子菌在免疫功能低下和免疫功能正常患者中引起真菌瘤样病变的病例。本病例报告描述了一种常见皮肤癣菌感染的不寻常表现，文献综述总结了认识皮肤癣菌感染非典型表现的重要性。此类感染在免疫功能低下患者中可能需要更积极的治疗。
