Background Duodenal adenocarcinoma (DA) with skin metastasis as initial manifestation is clinically rare. In this study, we report a rare case of skin metastasis of DA. Case presentation An 84-year-old male patient developed multiple ecchymoses on the trunk and lower extremities. Physical examination showed that the ecchymosis was dark red and had a hard texture, but showed no bulging, rupture, or tenderness. The skin biopsy implied skin metastatic adenocarcinoma. After an endoscopic duodenal biopsy, the patient was finally diagnosed with DA with skin metastasis. The patient received two courses of oral treatment of Tegafur (40 mg, bid d1–d14). However, the patient stopped taking Tegafur because of its poor effect and received Chinese medicine as a replacement treatment. Unfortunately, he was lost to follow-up. Conclusions Early diagnosis of DA metastasis is of significant importance as prognosis of these patients is poor.

中文翻译：

---

以皮肤转移为首发表现的十二指肠腺癌一例报告

背景 以皮肤转移为首发表现的十二指肠腺癌 (DA) 在临床上很少见。在这项研究中，我们报告了罕见的 DA 皮肤转移病例。病例介绍 一名 84 岁男性患者躯干和下肢出现多处瘀斑。体格检查：瘀斑呈暗红色，质地坚硬，但未见隆起、破裂或压痛。皮肤活检提示皮肤转移性腺癌。经内镜十二指肠活检，最终确诊为 DA 伴皮肤转移。患者接受了两个疗程的替加氟口服治疗（40 mg，bid d1-d14）。但因效果不佳，患者停止服用替加氟，转而接受中药替代治疗。不幸的是，他失去了跟进。