每日一题_2025.01.09

A 66-year-old woman with a history of metastatic breast cancer presented with a 1-month history of an asymptomatic, lacy rash on her left thigh. The rash did not vary with changes in environmental temperature. Her breast cancer treatment had been interrupted 3 months before presentation by the coronavirus disease 2019 pandemic. Physical examination was notable for an irregular, broken, netlike pattern of mottling on the left thigh that extended to the knee and lower leg. Testing for autoimmune conditions, thrombophilia, and coagulation disorders was negative. A skin-biopsy sample obtained from the left thigh showed atypical large cells within the vasculature of the reticular dermis that were positive for cytokeratin 7 and GATA-binding protein 3 on immunohistochemical staining. What is the diagnosis?

一位66岁、有转移性乳腺癌病史的女性，出现左大腿上无症状的、呈网状的皮疹，持续1个月。该皮疹不会因环境温度变化而改变。她的乳腺癌治疗在3个月前因2019冠状病毒病大流行而中断。体格检查显示左大腿上有不规则、断裂的网状斑驳图案，延伸至膝盖和小腿。自身免疫疾病、血栓形成倾向和凝血障碍的检测结果均为阴性。从左大腿获取的皮肤活检样本显示网状真皮血管内有细胞角蛋白7和GATA结合蛋白3阳性的异型大细胞。诊断是什么？

A. Cutis marmorata大理石样皮肤

B. Erythema ab igne火激红斑

C. Intravascular lymphoma血管内淋巴瘤

D. Livedo racemosa网状紫斑

E. Livedo reticularis网状青斑

答案解析：

诊断为因肿瘤栓塞引起的网状紫斑（livedo racemosa）。网状紫斑是一种由皮肤血流病理性中断引起的破碎网状皮肤变色模式。这种模式与网状青斑（livedo reticularis）的更均匀、连续的网状模式不同，后者可能出现在病理性或生理性（例如寒冷暴露）状态中。

正确答案：D