case_images: PMC11317433_01
case_images: Clinical course. The figure shows the clinical course up to nephrectomy. The timing of kidney biopsy, hemodialysis and nephrectomy is indicated by thick arrows. Sitagliptin was given at Cre 1.2 mg/dL and was stopped when Cre fell to 2.2 mg/dL; alogliptin was started at Cre 3.0 mg/dL; hemodialysis was started when Cre reached 7.5 mg/dL.
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case_images: The subsequent progression of renal function decline was slow ( Figure 1 ).This patient was admitted to investigate the cause of kidney impairment. No drugs were used that might contribute to TMA-like lesions, except for DPP4 inhibitors ( Figure 1 ).
case_images: Kidney biopsy and surgical specimen. (A, B) Tubulointerstitial fibrosis and tubular atrophy are observed in approximately 70% of the cortical area. (A) Masson trichrome staining. (B) Periodic acid-Schiff (PAS) staining. (C) Many of the preserved glomeruli show prominent fibrotic thickening (black arrow) of the glomerular basement membrane (GBM) of Bowman's capsule and duplication (white arrow) of the GBM. Periodic acid methenamine silver and Masson staining. (D) Glomerular endothelial cell proliferation (arrow) was observed. PAS staining. (E) Immunofluorescence microscopy reveals linear fluorescence of immunoglobulin G (arrow) along the GBM, Bowman's capsule, and tubular basement membrane. (F) Electron microscopy reveals endothelial cell proliferation (black arrow) with mesangiolysis (arrowhead) and subendothelial edema (white arrow). The GBM thickened to a width of 400-500 nm. (G) Two biopsy specimens showed clear cell renal cell carcinoma(arrow). Hematoxylin and eosin staining: original magnification x200. (H) split section of the surgical specimen. A tumor(arrow), 9-10 mm in size, was found in the surgical specimen in the lower pole of the right kidney. (I) Histology also confirmed clear cell renal cell carcinoma(arrow). Hematoxylin and eosin staining; original magnification x400.
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case_images: Tubulointerstitial fibrosis and atrophy with thickening of the tubular basement membrane were observed in approximately 70% of the cortical area ( Figures 2A, B ). Many of the preserved glomeruli showed fibrotic thickening of the basement membrane of the Bowman's capsule ( Figure 2C ). Duplication of the glomerular basement membrane (GBM) ( Figure 2C ) and endothelial cell proliferation were observed ( Figure 2D ). Immunofluorescence microscopy revealed linear fluorescence of IgG along the glomerular basement membrane (GBM), Bowman's capsule, and tubular basement membrane ( Figure 2E ), but staining for IgA, IgM, C3, and C1q was negative. The GBM was thickened to a width of 400-500 nm ( Figure 2F ); however, electron-dense deposits were not observed. Two biopsy specimens showed clear cell renal cell carcinoma (RCC), characterized by proximal tubular cell-like tumor cells with pale or acidophilic cytoplasms ( Figure 2G ). The surgical specimen contained a tumor, 9 mm in size, in the lower pole of the right kidney ( Figure 2H ). The size of the tumor cell nucleus was equivalent to that of the nucleus of the surrounding tubules (grade 1, Fuhrman grade 1, INFalpha, pT1a) ( Figure 2I ).
case_images: Diagnostic imaging. (A) Computed tomography (CT) scan before contrast enhancement. (B) CT scan immediately after contrast enhancement; white arrow indicates hypervascular staining (Equivalent to renal cancer). (C) Magnetic resonance imaging; Black arrow indicates mass, 9 mm in size (Equivalent to renal cancer) in the lower pole of the right kidney. White arrow confirmed the presence of a right adrenal tumor.
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case_images: A hypervascular stain, 8 mm in size, was observed in the lower pole of the right kidney ( Figure 3 ).