Department of Diagnostic Pathology, Nippon Medical School Hospital, Tokyo, Japan.
Department of Integrated Diagnostic Pathology, Nippon Medical School, Tokyo, Japan.
Pathol Int. 2022 Jan;72(1):65-71. doi: 10.1111/pin.13179. Epub 2021 Oct 12.
An 85-year-old man with a history of aortic dissection suddenly fainted, underwent cardiac heart arrest, and died. An autopsy was performed, but the cause of death was not grossly identified. Congo red staining detected amyloid deposits in systemic organs, including the heart, lungs, liver, and kidneys. Immunohistochemical (IHC) analysis revealed immunoglobulin (Ig) λ light chain (-λ) in systemic blood vessels and transthyretin (TTR) in the heart and lungs. Ig-λ was predominantly positive in the blood vessels of the lungs, while TTR was detected in the alveolar septum. In the heart, Ig-λ was positive in the endocardium and blood vessels, and TTR was positive in nodular deposits between cardiomyocytes. The concurrent deposition of Ig-λ and TTR in the heart was further substantiated by laser microdissection (LMD)-liquid chromatography-tandem mass spectrometry (LC-MS/MS) at each deposition site. Despite systemic deposition of Ig-λ, bone marrow biopsy findings were not diagnostic for multiple myeloma. In summary, we present an autopsy case of concurrent Ig-λ and TTR deposition as revealed by IHC and LC-MS/MS. When Congo red staining and IHC results are indeterminate due to the deposition of multiple amyloid proteins, LMD-LC-MS/MS is useful for determining the precursor protein.
一位 85 岁男性，有主动脉夹层病史，突发晕厥，发生心脏骤停后死亡。行尸检检查，但大体上未能明确死因。刚果红染色显示系统性器官（包括心脏、肺、肝和肾）有淀粉样沉积物。免疫组化（IHC）分析显示系统性血管中有免疫球蛋白（Ig）λ轻链（-λ），心脏和肺部有转甲状腺素（TTR）。Ig-λ 在肺部血管中呈强阳性，而 TTR 在肺泡隔中检出。在心脏，Ig-λ 在心内膜和血管中呈阳性，TTR 在心肌细胞间的结节状沉积物中呈阳性。通过激光微切割（LMD）-液相色谱-串联质谱（LC-MS/MS）在每个沉积部位进一步证实了心脏中 Ig-λ 和 TTR 的共存沉积。尽管存在系统性 Ig-λ 沉积，但骨髓活检结果对多发性骨髓瘤无诊断意义。总之，我们通过 IHC 和 LC-MS/MS 呈现了一例同时存在 Ig-λ 和 TTR 沉积的尸检病例。当刚果红染色和 IHC 结果因多种淀粉样蛋白沉积而不确定时，LMD-LC-MS/MS 有助于确定前体蛋白。
