While amoebic infection is widely known as a cause of gastroenteritis, keratitis, and meningoencephalitis, amoebae are challenging to recognize at unexpected sites. Despite multiple case reports of sinonasal amoebiasis, amoebic infection is not regularly considered in the differential diagnosis of sinonasal necroinflammatory disease. Here, we aim to characterize the pathologic features of sinonasal amoebiasis to facilitate better recognition. We identified sinonasal amoebiasis in 4 men, median age of 67 years (range: 37 to 71 y). All were immunocompromised, including 2 with chronic lymphocytic leukemia, 1 with human immunodeficiency virus, and 1 with human immunodeficiency virus and kidney transplant. Patients presented with nasal mucosal necrosis or polypoid masses, with facial ulceration in 1 patient and distant dermal nodules in another. Biopsies displayed extensive necrotic debris and inflammation. Although amoebic cysts were abundant in 3 cases, they were mistaken for yeast at frozen section in 1 case; 1 case showed only rare trophozoites that were not recognized on initial biopsy. Periodic acid Schiff and Grocott Methenamine Silver stains highlighted the organisms, and polymerase chain reaction confirmed Acanthamoeba species in 3 cases tested. 2 patients responded well to antiprotozoal medications, but 2 died of disease. Overall, sinonasal amoebiasis presents as a necroinflammatory process in patients immunocompromised for various reasons. Amoebae can mimic other organisms or be incredibly scarce, requiring active consideration to recognize amoebiasis and differentiate it from overlapping conditions like invasive fungal sinusitis, granulomatosis with polyangiitis, and natural killer/T-cell lymphoma. Because sinonasal amoebiasis is highly treatable when diagnosed promptly, pathologists play a critical role in the recognition of this rare necroinflammatory disease.

虽然阿米巴感染被广泛认为是胃肠炎、角膜炎和脑膜脑炎的原因，但阿米巴在意想不到的地方很难识别。尽管有多例鼻窦阿米巴病病例报告，但在鼻窦炎性坏死病的鉴别诊断中并不经常考虑阿米巴感染。在这里，我们旨在描述鼻窦阿米巴病的病理特征，以便更好地识别。我们在 4 名男性中发现了鼻窦阿米巴病，中位年龄为 67 岁（范围：37 至 71 岁）。均为免疫功能低下，其中慢性淋巴细胞白血病2例，人类免疫缺陷病毒1例，人类免疫缺陷病毒合并肾移植1例。患者表现为鼻黏膜坏死或息肉样肿块，1例面部溃疡，1例远处真皮结节。活检显示广泛的坏死碎片和炎症。3例阿米巴囊肿虽多，但1例冰冻切片误为酵母菌；1 例仅显示在初始活检时未被识别的罕见滋养体。高碘酸 Schiff 和 Grocott Methenamine 银染突出了生物体，聚合酶链反应证实棘阿米巴属3例进行了检测。2 例患者对抗原生动物药物反应良好，但 2 例死于疾病。总体而言，鼻窦阿米巴病在由于各种原因免疫功能低下的患者中表现为坏死性炎症过程。变形虫可以模仿其他生物体或非常稀少，需要积极考虑识别变形虫病并将其与侵袭性真菌性鼻窦炎、肉芽肿性多血管炎和自然杀伤/T 细胞淋巴瘤等重叠病症区分开来。由于鼻窦阿米巴病在及时诊断时是高度可治疗的，因此病理学家在识别这种罕见的坏死性炎症疾病方面发挥着关键作用。