Division of Anti-Ageing Medicine, Center for Molecular Medicine, Jichi Medical University, 3311-1 Yakushiji, Shimotsuke, Tochigi, 329-0498, Japan.
Division of Nephrology, Department of Internal Medicine, Jichi Medical University, 3311-1 Yakushiji, Shimotsuke, Tochigi, 329-0498, Japan.
CEN Case Rep. 2024 Apr;13(2):104-109. doi: 10.1007/s13730-023-00807-5. Epub 2023 Jul 11.
Paraneoplastic IgA nephropathy (IgAN) is an underrecognized condition in which malignancy manifests as symptoms of IgAN, and it remains controversial regarding their mechanistic relation between IgAN and malignancy. Herein, we report a case of a 68-year-old Japanese man with glottic cancer who developed nephrotic syndrome as a clinical manifestation of IgAN. Renal biopsy revealed diffuse proliferative glomerulonephritis with glomerular capillary IgA deposition that is a rare subtype of IgAN. After complete remission of the glottic cancer by irradiation, proteinuria and hematuria disappeared. Based on his clinical course, we diagnosed paraneoplastic IgAN. Therefore, we should consider the possibility that IgAN with glomerular capillary IgA deposition might be paraneoplastic glomerulopathy especially before initiating immunosuppressive therapy. The patient thereafter developed prostate cancer and hepatocellular cancer, but IgAN did not recur. The association of IgAN specifically with the glottic cancer in this triple-cancer patient may suggest a potential link between IgAN and mucosal cancer. Because galactose-deficient IgA1 (Gd-IgA1) was observed in the similar pattern as IgA, Gd-IgA1 also may play an important role in the pathogenesis of paraneoplastic IgAN.
副肿瘤性 IgA 肾病（IgAN）是一种未被充分认识的疾病，其特征为恶性肿瘤表现为 IgAN 的症状，而 IgAN 与恶性肿瘤之间的机制关系仍存在争议。在此，我们报告一例 68 岁日本男性，患有声门癌，表现为 IgAN 的肾病综合征。肾活检显示弥漫性增生性肾小球肾炎伴肾小球毛细血管 IgA 沉积，为 IgAN 的罕见亚型。声门癌经放疗完全缓解后，蛋白尿和血尿消失。根据他的临床病程，我们诊断为副肿瘤性 IgAN。因此，我们应该考虑存在肾小球毛细血管 IgA 沉积的 IgAN 可能为副肿瘤性肾小球病的可能性，特别是在开始免疫抑制治疗之前。此后，该患者又发生了前列腺癌和肝细胞癌，但 IgAN 未复发。三重癌患者的 IgAN 与声门癌的特异性关联可能提示 IgAN 与黏膜癌之间存在潜在联系。由于观察到 Gd-IgA1（半乳糖缺乏 IgA1）与 IgA 具有相似的模式，因此 Gd-IgA1 也可能在副肿瘤性 IgAN 的发病机制中发挥重要作用。
