Nephrogenic adenoma (NA) is an epithelial lesion that usually occurs in the mucosa of the urinary tract. Rare cases of deep infiltrative or perinephric lesions have also been reported. Recently, NA with characteristic fibromyxoid stroma (fibromyxoid NA) has been proposed as a distinct variant. Although shedding of distal renal tubular cells due to urinary tract rupture has been postulated as the cause of NA in general, the mechanism underlying extraurinary presentation of NA and fibromyxoid stromal change in fibromyxoid NA remains unknown. In this study, we performed mass spectrometry (MS) analysis in a case of perinephric fibromyxoid NA of an 82-year-old man who underwent right nephroureterectomy for distal ureteral cancer. The patient had no prior history of urinary tract injury or radiation. Periodic acid-Schiff staining-positive eosinophilic structureless deposits in the stroma of fibromyxoid NA were microdissected and subjected to liquid chromatography/MS. The analysis revealed the presence of a substantial amount of uromodulin (Tamm−Horsfall protein). The presence of urinary content in the stroma of perinephric fibromyxoid NA suggests that urinary tract rupture and engraftment of renal tubular epithelial cells directly cause the lesion.

中文翻译：

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质谱法鉴定肾周纤维粘液样肾源性腺瘤基质中的尿调节素沉积

肾源性腺瘤（NA）是一种通常发生在泌尿道粘膜的上皮病变。也有罕见的深部浸润或肾周病变病例报道。最近，具有特征性纤维粘液样基质（纤维粘液样NA）的NA被认为是一种独特的变体。尽管尿路破裂引起的远端肾小管细胞脱落被认为是 NA 的一般原因，但 NA 尿外呈现和纤维粘液样 NA 中纤维粘液样基质变化的机制仍不清楚。在这项研究中，我们对一名 82 岁男性肾周纤维粘液样 NA 病例进行了质谱 (MS) 分析，该男性因远端输尿管癌接受了右肾输尿管切除术。患者既往没有尿路损伤或放射史。对纤维粘液样 NA 基质中高碘酸希夫染色阳性的嗜酸性无结构沉积物进行显微解剖，并进行液相色谱/质谱分析。分析显示存在大量的尿调节素（Tamm-Horsfall 蛋白）。肾周纤维粘液样NA基质中尿内容物的存在表明尿路破裂和肾小管上皮细胞的植入直接导致病变。