The “lentiform fork sign” is a rare MRI sign which affects the posterior limb of the internal capsule, the external capsule, and extends posteriorly to form a fork-like appearance. It has been reported exclusively in disorders with metabolic acidosis, such as uremic encephalopathy, mitochondrial disorders, methanol/ethylene glycol intoxication, etc. It is considered to represent vasogenic edema and is often reversible. We describe a 73-year old female with a 2-month history of rapidly deteriorating imbalance, bradykinesia, confusion, and disorientation. At examination, she was encephalopathic. She had a pyramidal and rigid-akinetic parkinsonian syndrome, with signs of polyneuropathy. MRI revealed the “lentiform fork sign”. She exhibited a high ANA titer, positive anti-dsDNA, anti-ENA, and anti-β2GPI-IgM antibodies, as well as positive cerebrospinal fluid IgG and albumin indices. No metabolic acidosis was recorded. A diagnosis of systemic lupus erythematosus (SLE) was established. She was treated initially with methylprednisolone, followed by hydroxychloroquine, with complete remission of her symptoms and disappearance of the “lentiform fork sign”. We present a case of a patient with SLE, harboring the “lentiform fork sign”, in the absence of metabolic acidosis. Differential diagnosis of the “lentiform fork sign” should be expanded to include autoimmune disorders, even in the absence of metabolic acidosis.

“扁形叉征”是一种罕见的MRI征兆，会影响内囊的后肢，外囊，并向后延伸形成叉状外观。仅在代谢性酸中毒疾病中有报道，例如尿毒症脑病，线粒体疾病，甲醇/乙二醇中毒等。它被认为代表血管性水肿，通常是可逆的。我们描述了一位73岁的女性，具有2个月迅速恶化的失衡，运动迟缓，精神错乱和迷失方向的历史。在检查时，她患有脑病。她患有锥体性和刚性运动性帕金森综合症，伴有多发性神经病的迹象。MRI显示“叉状叉状”。她展示了高ANA滴度，抗dsDNA，抗ENA和抗β2GPI-IgM抗体，以及阳性的脑脊液IgG和白蛋白指数。没有记录到代谢性酸中毒。建立了系统性红斑狼疮（SLE）的诊断。最初接受甲基强的松龙治疗，然后接受羟氯喹治疗，症状完全缓解，“长形叉状征”消失。我们提出一例患有SLE的患者，在没有代谢性酸中毒的情况下带有“长形叉状征”。即使没有代谢性酸中毒，也应扩大对“豆状叉状”的鉴别诊断，以包括自身免疫性疾病。症状完全缓解，“叉状叉状”消失。我们提出一例患有SLE的患者，在没有代谢性酸中毒的情况下带有“长形叉状征”。即使没有代谢性酸中毒，也应扩大对“豆状叉状”的鉴别诊断，以包括自身免疫性疾病。症状完全缓解，“叉状叉状”消失。我们提出一例患有SLE的患者，在没有代谢性酸中毒的情况下带有“长形叉状征”。即使没有代谢性酸中毒，也应扩大对“豆状叉状”的鉴别诊断，以包括自身免疫性疾病。