Capgras syndrome associated with limbic encephalitis in a patient with diffuse large B-cell lymphoma

We report the case of a patient with insidious onset and slowly progressive cognitive impairment, behavioral symptoms, temporal lobe seizures and delusional thoughts typical of delusional misidentification syndromes. Clinical presentation along with extensive diagnostic work-up revealed limbic encephalitis secondary to diffuse large B-cell lymphoma. The patient underwent immunotherapy with high-dose corticosteroid but no significant improvement was observed. No specific treatment for lymphoma was performed because the patient died of septic shock following a nosocomial respiratory infection. Delusional misidentification syndromes are an unusual and unique form of cognitive impairment in which a patient consistently misidentifies persons, places, objects, or events. Capgras syndrome is the most common subtype of this disorder, being defined by the recurrent and transient belief that someone close has been substituted by an imposter. These entities are generally associated with neurodegenerative diseases and psychiatric disturbances. Rare reports of associations between misidentification syndromes and autoimmune diseases such as multiple sclerosis have been published, but no papers address a correlation with limbic encephalitis or lymphoma.

本研究报告1例起病隐匿、呈缓慢进展性认知障碍、行为异常、颞叶癫痫及妄想性思维的患者，其临床表现符合妄想性错认综合征（delusional misidentification syndromes）的典型特征。结合患者的临床表现与全面的诊断检查，最终确诊为继发于弥漫大B细胞淋巴瘤（diffuse large B-cell lymphoma）的边缘性脑炎（limbic encephalitis）。患者接受了大剂量糖皮质激素免疫治疗，但未获得显著症状改善。因患者后续因院内呼吸道感染引发感染性休克死亡，故未针对淋巴瘤开展特异性治疗。妄想性错认综合征是一类罕见且特殊的认知障碍类型，患者会持续出现对人物、地点、物品或事件的错认。卡普格拉综合征（Capgras syndrome）是该类障碍最常见的亚型，其核心特征为患者反复且短暂地坚信身边亲近之人已被冒充者替换。此类综合征通常与神经退行性疾病及精神障碍相关。目前仅有少数文献报道错认综合征与多发性硬化（multiple sclerosis）等自身免疫性疾病存在关联，但尚未有研究探讨其与边缘性脑炎或淋巴瘤的相关性。