A man in his 40s with newly diagnosed acute myelogenous leukemia (AML) arising from myelodysplasia presented with fever, cough, abdominal pain, difficulty swallowing, and 1 month of neutropenia. He had abruptly developed a painful eruption on his scalp, face, and left leg 24 hours prior to presentation after being scratched in these areas by his pet cat. The patient had not received any chemotherapy or antimicrobial prophylaxis. Physical examination revealed an ill-appearing, diaphoretic, thin man with multiple erythematous to violaceous, tender, edematous, targetoid nodules and plaques with central dusky appearance on the left forearm and right upper thigh (Figure, A). Vital signs included temperature of 39.7° C, blood pressure of 141/69 mm Hg, and pulse of 122 bpm. His white blood cell count was 1.8 × 10³/µL (reference range, 4.5-11 × 10³/µL; to convert to ×10⁹/L, multiply by .001), and absolute neutrophil count was 246 cells/µL (reference range, 1520-6370 cells/µL). Other laboratory values were remarkable for a red blood cell count of 2.13 × 10⁶/µL (reference range, 3.9-5.5 × 10⁶/µL; to convert to ×10¹²/L, multiply by 1), hemoglobin of 6.1 g/dL (reference range, 14-17.5 g/dL; to convert to g/L, multiply by 10), and platelet count of 14 × 10³/µL (reference range 150-350 × 10³/µL, to convert to ×10⁹/L, multiply 1). Cellular cytogenetics of his AML were notable for a 5q deletion and p53 mutation. Punch biopsy specimens from the right arm and left thigh were performed for histopathologic evaluation and tissue culture. A brisk neutrophilic infiltrate was seen on histopathology (Figure, B).

四十多岁的一名男子，因骨髓增生异常而新诊断为急性骨髓性白血病（AML），伴有发烧，咳嗽，腹痛，吞咽困难和中性粒细胞减少症1个月。出诊前24小时，他被宠物猫抓挠，在头皮，面部和左腿上突然出现疼痛性喷发。该患者未接受任何化学疗法或抗生素预防。体格检查发现一个外表不适，发汗，瘦弱的人，在左前臂和右大腿上有多处红斑到紫红色，嫩嫩，水肿，目标样结节和斑块，中央呈暗淡的外观（图A）。生命体征包括体温39.7°C，血压141/69 mm Hg和脉搏122 bpm。他的白细胞计数为1.8×10 ³/ µL（参考范围4.5-11×10 ³ / µL；转换为×10 ⁹ / L，乘以.001），中性粒细胞绝对计数为246个细胞/ µL（参考范围1520-6370个细胞/ µL） 。其他实验室值也很出色，红细胞计数为2.13×10 ⁶ / µL（参考范围为3.9-5.5×10 ⁶ / µL；转换为×10 ¹² / L，乘以1），血红蛋白为6.1 g / dL（参考范围14-17.5 g / dL；转换为g / L，乘以10），血小板计数为14×10 ³ / µL（参考范围150-350×10 ³ / µL，转换为× 10 ⁹/ L，乘以1）。他的AML的细胞遗传学特征是5q缺失和p53突变。对右臂和左大腿的穿刺活检标本进行组织病理学评估和组织培养。在组织病理学上观察到轻度的嗜中性浸润（图B）。