Liapis Helen, Boils Christie, Hennigar Randolph, Silva Fred
Nephropath, Little Rock, AR, 72211.
Nephropath, Little Rock, AR, 72211.
Hum Pathol. 2016 Aug;54:25-30. doi: 10.1016/j.humpath.2016.02.026. Epub 2016 Mar 30.
Five hundred eighty renal biopsies from a pool of 27850 archived cases were identified in which a myoglobin stain was performed because of atypical casts. Two hundred and thirty-eight (41%) of these biopsies were found to be positive for myoglobin casts. The morphology of the myoglobin casts ranged from light, almost translucent and refractile, to pink, to dark red and slightly brown granular casts by hematoxylin and eosin, to beaded globular casts that stained brightly fuchsinophilic with Masson trichrome and partially argyrophilic with silver methenamine. All biopsies displayed acute tubular injury associated with intratubular debris and thinning and vacuolization of tubular epithelium. Approximately 20% of myoglobin-positive biopsies showed calcium oxalate or phosphate deposition. Positive myoglobin staining was present in casts, proximal tubular epithelial cells without casts, and also dehisced epithelial cells. Collecting ducts and occasionally the distal tubular epithelium also stained positive. One case showed concurrent myeloma cast nephropathy with "fractured" casts and translucent myoglobin-positive casts. Herein, we describe the morphologic spectrum of myoglobin-positive casts. We conclude that utilization of myoglobin immunohistochemistry is advantageous and, when not available, knowledge of the morphologic spectrum is important.
在27850例存档病例中，有580例肾活检因存在非典型管型而进行了肌红蛋白染色。其中238例（41%）活检显示肌红蛋白管型阳性。肌红蛋白管型的形态各异，苏木精-伊红染色下，从浅色、几乎半透明且有折光性，到粉红色，再到暗红色和略带棕色的颗粒管型，马松三色染色下为串珠状球形管型，呈亮品红色嗜染，六胺银染色呈部分嗜银性。所有活检均显示急性肾小管损伤，伴有肾小管内碎屑以及肾小管上皮变薄和空泡化。约20%肌红蛋白阳性的活检显示有草酸钙或磷酸盐沉积。肌红蛋白染色阳性见于管型、无管型的近端肾小管上皮细胞以及脱落的上皮细胞。集合管以及偶尔远端肾小管上皮也呈阳性染色。1例同时显示骨髓瘤管型肾病，伴有“断裂”管型和半透明的肌红蛋白阳性管型。在此，我们描述了肌红蛋白阳性管型的形态谱。我们得出结论，肌红蛋白免疫组化的应用是有益的，若无法进行免疫组化，了解形态谱也很重要。
