Morrison Annie O, Morris Robert, Shannon Amie, Lauer Scott R, Guarner Jeannette, Kraft Colleen S
From the Departments of Pathology and Laboratory Medicine
From the Departments of Pathology and Laboratory Medicine Dermatology, Emory University, Atlanta, GA.
Am J Clin Pathol. 2016 Feb;145(2):266-70. doi: 10.1093/ajcp/aqv081. Epub 2016 Jan 22.
Free-living amoebas are exceedingly rare causes of cutaneous infections and present unique diagnostic and therapeutic challenges. We describe a case of disseminated acanthamoebiasis with cutaneous manifestations and summarize additional diagnostic, prognostic, and therapeutic highlights.
A 58-year-old man with relapsed chronic lymphocytic leukemia had several weeks of progressive, painful ulcerations on the forehead, arms, abdomen, and thighs. A biopsy was performed for histopathologic evaluation.
The biopsy specimen showed inflammatory infiltrate with abscess formation involving the epidermis, dermis, and subcutis. Scattered cells showed nuclei with a prominent central karyosome, dispersed chromatin, and either abundant foamy basophilic cytoplasm or two well-demarcated cytoplasmic walls. Acanthamoeba species was confirmed by polymerase chain reaction from the formalin-fixed, paraffin-embedded tissue.
Cutaneous lesions from acanthamoebiasis are exceptionally rare but should be included in the differential diagnosis of necrotic cutaneous lesions in immunocompromised patients. Although infrequently encountered, pathologists need to be aware of the morphologic features of free-living amoebas. Immunohistochemical and molecular studies can confirm the diagnosis. Multiagent treatment regimens, when initiated empirically, have been more successful than single-agent regimens, but infections involving the central nervous system are almost universally fatal.
自由生活阿米巴是皮肤感染极为罕见的病因，带来独特的诊断和治疗挑战。我们描述一例有皮肤表现的播散性棘阿米巴病病例，并总结其他诊断、预后和治疗要点。
一名58岁复发慢性淋巴细胞白血病男性患者，前额、手臂、腹部和大腿出现数周进行性疼痛性溃疡。进行活检以进行组织病理学评估。
活检标本显示炎症浸润伴脓肿形成，累及表皮、真皮和皮下组织。散在细胞显示细胞核有突出的中央核仁、分散的染色质，以及丰富的泡沫状嗜碱性细胞质或两个界限分明的细胞质壁。通过对福尔马林固定、石蜡包埋组织进行聚合酶链反应确认了棘阿米巴属。
棘阿米巴病引起的皮肤病变极为罕见，但在免疫功能低下患者坏死性皮肤病变的鉴别诊断中应予以考虑。尽管很少遇到，但病理学家需要了解自由生活阿米巴的形态学特征。免疫组织化学和分子研究可确诊。经验性启动的多药治疗方案比单药治疗方案更成功，但累及中枢神经系统的感染几乎普遍致命。
