雙下肢慢性潰瘍傷口常見於周邊動脈血管阻塞、自體免疫疾病如血管炎等疾病，但其好發病灶位置、潰瘍傷口大小、型態及傷口對稱性等皆需仔細評估和辨別，進而影響鑑別診斷方向與處置。本案例報告描述一位69歲女性患者，患有末期腎臟衰竭，雙小腿皮膚病灶呈現慢性潰瘍傷口。初步臆測診斷為下肢周邊動脈血管阻塞疾病，經藥物與手術治療後潰瘍傷口未見改善，並出現劇烈疼痛、傷口延伸至雙大腿內側脂肪較多處。鑒於臨床表現高度懷疑為罕見疾病之鈣化防禦症，透過病理組織切片而確定診斷。隨後接受硫代硫酸鈉藥物併高壓氧治療、多次接受清創及植皮手術，慢性潰瘍傷口逐漸癒合且順利出院。鈣化防禦症所引起的潰瘍傷口，臨床表徵上與周邊動脈 血管阻塞及Warfarin導致的潰瘍傷口極為相似。腎臟衰竭患者出現難以癒合的潰瘍傷口，應將鈣化防禦症納入鑑別診斷之一，以免延誤治療導致反覆感染，最終引發敗血性休克及死亡。

Chronic lower limb ulcers are commonly associated with conditions such as peripheral arterial occlu-sive disease and autoimmune vasculitis. However, precise evaluation of ulcer location, size, morphol-ogy, and symmetry is crucial for accurate differential diagnosis and appropriate treatment. This case report describes a 69-year-old female patient with end-stage renal disease who presented with chronic ulcerations over both calves. The initial diagnosis was peripheral arterial occlusive disease; however, the ulcers failed to improve following pharmacologic and surgical interventions and progressively extended to the medial thighs, accompanied by severe pain. Given the clinical presentation, calciphy-laxis was highly suspected and later confirmed through histopathological examination. The patient was treated with intravenous sodium thiosulfate, adjunctive hyperbaric oxygen therapy, and underwent multiple surgical debridements and skin grafting. Gradual wound healing was achieved, and the pa-tient was successfully discharged. Ulcers caused by calciphylaxis can closely mimic those of periph-eral arterial occlusion or warfarin-induced skin necrosis. In patients with renal failure who present with non-healing, painful ulcers, calciphylaxis should be included in the differential diagnosis to avoid delays in treatment, reduce the risk of recurrent infections, and prevent progression to septic shock and mortality.