A 73-year-old woman presented to the dermatology clinic with an 11-month history of an evolving pruritic, erythematous rash on her thighs, buttocks, trunk, and axillae (Panel A). The rash initially consisted of pruritic annular lesions with central duskiness and was treated with prednisone and antihistamines without improvement. 

73岁女性因进行性瘙痒性皮疹11月就诊皮肤科，皮疹分布在双侧大腿、臀部、躯干和腋窝。皮疹初发时为环形皮疹伴中央部颜色稍深，曾接受激素及抗组胺药治疗，症状无改善

The rash evolved into polycyclic erythematous plaques during the next 4 months, during which abdominal pain, vomiting, and diarrhea also developed. 

皮疹在接下来的4月进展为多形性红斑样皮损，同时伴腹痛、呕吐及腹泻。

After colonoscopy and imaging, stage IIA anal squamous-cell carcinoma was diagnosed. 

结肠镜检查及病理提示 直肠IIA 期鳞癌。

Before undergoing radiation and chemotherapy, the patient was referred to the dermatology clinic for assessment of the persistent, evolving rash.

患者在行放化部前，曾请皮肤科医师会诊。

She received a clinical diagnosis of erythema gyratum repens, a rare paraneoplastic rash usually associated with breast, lung, or esophageal cancer. 

患者诊断为匍匐状环形红斑，为罕见的一种副癌 皮疹，通常原发肿瘤为乳腺癌、肺癌或食管癌。

The patient started treatment with topical glucocorticoids and began a trial of gabapentin for pruritus. The rash abated 3 months after the initiation of chemotherapy and radiation (Panel B). At a follow-up visit at 8 months, the cancer remained in remission, and the rash had not recurred.

患者予皮肤激素软膏及口服加巴喷丁止痒对症。放化疗3月后皮疹减轻。治疗8月后随访，患者直肠肿瘤未复发，皮疹未复发。