Pediatric early-phase anorexia nervosa without hypokalemia exhibiting acute tubular injury: a case report

Anorexia nervosa can lead to kidney complications. Few studies reported kidney biopsy results in young adults, most of whom had chronic anorexia nervosa, and kidney biopsy findings in pediatric patients with early-phase anorexia nervosa are rarely reported. A 14-year-old girl who lost weight due to excessive exercise and reduced diet was admitted for kidney dysfunction. She was 147 cm tall and weighed 32.9 kg, with a body mass index of 15.2 kg/m2. She was 39 kg about a year earlier. Her heart rate and blood pressure were 30-40 beats/min and 108/68 mmHg, respectively. She had kidney dysfunction (estimated glomerular filtration rate, 56.6 mL/min/1.73 m2). Urine β2-microglobulin was slightly elevated (393 μg/L), and percent tubular phosphate reabsorption was low (75.2%), suggesting tubular damage; however, hypokalemia was absent. Kidney dysfunction did not improve with fluid loading. Kidney biopsy revealed that all glomeruli were intact, with no vasculitis, interstitial inflammation or fibrosis on light microscopy. However, proximal tubular epithelial walls were flattened and the brush border was absent, suggesting acute tubular injury. Immunofluorescent staining was negative for immunoglobulins and complement proteins, and electron microscopy showed no significant electron-dense deposition. The patient's serum creatinine gradually declined, normalizing on the 17th day of admission. Unlike previous reports in young adults, kidney dysfunction was observed even in the absence of hypokalemia in the current pediatric patient with early-phase anorexia nervosa. Proximal tubular injury in early-phase anorexia nervosa may be caused by bradycardia without hypokalemia, leading to subsequent kidney dysfunction.

Adverse effects of acute tubular injury on the glomerulus: contributing factors and mechanisms

The intricate relationship between tubular injury and glomerular dysfunction in kidney diseases has been a subject of extensive research. While the impact of glomerular injury on downstream tubules has been well-studied, the reverse influence of tubular injury on the glomerulus remains less explored. This paper provides a comprehensive review of recent advances in the field, focusing on key pathways and players implicated in the pathogenesis of tubular injury on glomerular dysfunction. Anatomical and physiological evidence supports the possibility of crosstalk from the tubule to the glomerulus, whereby various mechanisms contribute to glomerular injury following tubular injury. These mechanisms include tubular backleak, dysfunctional tubuloglomerular feedback, capillary rarefaction, atubular glomeruli, and the secretion of factors from damaged tubular epithelial cells. Clinical evidence further supports the association between even mild or recovered acute kidney injury and an increased risk of chronic kidney disease, including glomerular diseases. We also discuss potential therapeutic interventions aimed at mitigating acute tubular injury, thereby reducing the detrimental effects on glomerular function. By unraveling the complex interplay from tubular injury to glomerular dysfunction, we aim to provide insights that can enhance clinical management strategies and improve outcomes for patients with kidney disease.

Immunoglobulin G deposition on proximal tubules and the tubular basement membrane in acute tubular injury complicated with focal segmental glomerulosclerosis (FSGS): A possible prediction tool for subclinical FSGS

Immunofluorescent deposition of immunoglobulin G (IgG) in the tubular basement membrane (TBM) has been evaluated in the diagnosis of various diseases; however, few studies have investigated the immunofluorescence of acute tubular injury (ATI). Herein, we attempted to clarify IgG expression in the proximal tubular epithelium and TBM in ATI due to various causes. Patients with ATI with nephrotic-range proteinuria, including focal segmental glomerulosclerosis (FSGS, n = 18) and minimal change nephrotic syndrome (MCNS, n = 8), ATI with ischemia (n = 6), and drug-induced ATI (n = 7), were enrolled. ATI was evaluated by light microscopy. CD15 and IgG double staining and IgG subclass staining were performed to evaluate immunoglobulin deposition in the proximal tubular epithelium and TBM. IgG deposition was identified in the proximal tubules only in the FSGS group. Furthermore, IgG deposition in the TBM was observed in the FSGS group showing severe ATI. IgG3 was predominantly deposited by the IgG subclass study. Our results indicate that IgG deposition in the proximal tubular epithelium and TBM suggests the leaking of IgG from the glomerular filtration barrier and its reabsorption by proximal tubules, which may predict disruption of the glomerular size barrier, including subclinical FSGS. FSGS with ATI should be included as a differential diagnosis when IgG deposition in TBM is observed.

Serum Uromodulin Is a Possible Auxiliary Diagnostic Tool for Acute Tubular Injury and Acute Interstitial Nephritis: A Case Series

Recently, the usefulness of serum uromodulin (sUmod) as a novel renal biomarker has been attracting attention. Clinical evidence regarding sUmod measurements has been accumulated by analyzing cross-sectional data. However, little is known about the longitudinal data on sUmod. Therefore, we decided to investigate the variability of sUmod in patients with acute kidney injury due to different causes. High concentrations of sUmod have been observed in patients with acute tubular injury (ATI) and/or acute interstitial nephritis (AIN). sUmod could be used as an auxiliary diagnostic tool for ATI and AIN.

Clinicopathological features and short outcomes of oliguric acute tubular injury

PURPOSE

To explore the clinicopathological features and analyze the relevant risk factors and short-term renal outcomes of acute tubular injury (ATI) patients.

MATERIALS AND METHODS

A total of 83 patients with biopsy-proven ATI were included in this retrospective cohort study. Clinical characteristic and histological feature data were collected, and renal recovery at 1 month postbiopsy was recorded.

RESULTS

The severity of renal dysfunction, percentage of acute tubular lesions, interstitial inflammation and fibrosis of oliguric ATI patients were all significantly higher than those of nonoliguric patients. In the subgroup analysis of the oliguric patients, the serum creatinine and urinary microalbumin levels, severity of epithelial cell degeneration and cast formation of patients in the polyuric phase at biopsy were significantly lower than those of patients in the oliguric phase. A total of 59 patients had 1-month follow-up records, and complete renal recovery was observed in 42 patients. In the multivariate analysis, the total acute tubular injury area at biopsy was the most important independent risk factor for poor renal outcomes.

CONCLUSIONS

Oliguric ATI patients had severe clinicopathological conditions. The severity of tubular lesions seriously influenced renal function recovery, demonstrating the importance of renal biopsy in assessing the prognosis of patients with kidney disease.

Acute kidney injury due to intravenous detergent poisoning: A case report

BACKGROUND

Detergent poisoning mostly occurs through oral ingestion (> 85%), ocular exposure (< 15%), or dermal exposure (< 8%). Reports of detergent poisoning through an intravenous injection are extremely rare. In addition, there are very few cases of renal toxicity directly caused by detergents. Here, we report a unique case of acute kidney injury caused by detergent poisoning through an accidental intravenous injection.

CASE SUMMARY

A 61-year-old man was intravenously injected with 20 mL of detergent by another patient in the same room of a local hospital. The surfactant and calcium carbonate accounted for the largest proportion of the detergent. The patient complained of vascular pain, chest discomfort, and nausea, and was transferred to our institution. After hospitalization, the patient’s serum creatinine level increased to 5.42 mg/dL, and his daily urine output decreased to approximately 300 mL. Renal biopsy findings noted that the glomeruli were relatively intact; however, diffuse acute tubular injury was observed. Generalized edema was also noted, and the patient underwent a total of four hemodiafiltration sessions. Afterward, the patient’s urine output gradually increased whereas the serum creatinine level decreased. The patient was discharged in a stable status without any sequelae.

CONCLUSION

Detergents appear to directly cause renal tubular injury by systemic absorption. In treating a patient with detergent poisoning, physicians should be aware that the renal function may also deteriorate. In addition, timely renal replacement therapy may help improve the patient’s prognosis.

Role of progenitor cell marker CD133 in supporting diagnosis of collapsing glomerulopathy

Purpose

A previous immunofluorescent study suggests that, in collapsing glomerulopathy, most hyperplastic podocytes that stained positively for a progenitor cell marker CD133 are derived from CD133 + parietal epithelial cells. In pathology practice, not all renal biopsies with collapsing glomerulopathy show the typical morphologic features for this entity, which include florid podocyte hyperplasia, collapsing glomerular capillary loops, and cystic tubular dilation. This study was made to determine if CD133 staining using an immunohistochemical method can be used to confirm hyperplastic podocytes and identify extensive acute tubular injury in collapsing glomerulopathy.

Methods

Twenty-one collapsing glomerulopathy biopsies were stained for CD133 and compared with 15 biopsies with focal segmental glomerulosclerosis, not otherwise specified (FSGS).

Results

All patients with collapsing glomerulopathy were of African American descent with prominent renal failure and nephrotic range proteinuria. In contrast, the FSGS group consisted of patients from a variety of ethnic backgrounds with nephrotic range proteinuria but relatively low serum creatinine. The striking finding was that all collapsing glomerulopathy cases showed positive CD133 staining in the clusters of hyperplastic podocytes. There was significantly higher CD133-positive staining rate for hyperplastic podocytes (38%) in the glomeruli of the collapsing glomerulopathy group when compared to small clusters of hyperplastic podocytes in the FSGS group (8%). In addition, when compared to the relatively weak CD133 staining in the proximal tubules of the FSGS group, the proximal tubules of the collapsing glomerulopathy group all showed diffuse and strong CD133 staining as a feature of severe acute tubular injury, which corresponded to the high serum creatinine levels in these patients.

Conclusion

Our data indicate that the combination of the distinctive mosaic CD133 staining in hyperplastic podocytes and the diffuse tubular CD133 staining is helpful in supporting a diagnosis of collapsing glomerulopathy.

Supplementary Information

The online version contains supplementary material available at 10.1007/s11255-021-03078-0.

Post-mortem assessment of vimentin expression as a biomarker for renal tubular regeneration following acute kidney injury

BACKGROUND

Acute kidney injury (AKI) is a common cause of morbidity and mortality. It mainly targets the renal tubular epithelium with pathological changes, referred to as acute tubular injury. The latter is followed by a regenerative response that is difficult to visualize on routine hematoxylin and eosin (H&E) stains. In this study, we examined the regenerative capacity of renal tubules by correlating vimentin (VIM) immunohistochemical (IHC) expression and pathological findings of AKI and renal tubular regeneration (RTR) on H&E.

METHODS

We reviewed 23 autopsies performed in the clinical setting of AKI and RTR. VIM expression was scored in the renal cortical tubular epithelium using a statistical cutoff ≥ 3% for high expression and < 3% for low expression.

RESULTS

Of the 23 kidney tissues examined, seven (30.4%) had low VIM expression, and 16 (69.6%) had high VIM expression. Kidney tissues with evidence of AKI and RTR had significantly higher VIM expression. Renal peritubular microenvironment features showing regenerative changes on H&E were associated with high VIM expression. In the univariate model, kidney tissues with RTR were 18-fold more likely to have high VIM expression.

CONCLUSIONS

In conclusion, our findings suggest that VIM could serve as an IHC marker for RTR following AKI. However, correlation with H&E findings remains critical to excluding chronic tubular damage. Collectively, our preliminary results pave the way for future studies including a larger sample size to validate the use of VIM as a reliable biomarker for RTR.

Renal post-mortem findings in myeloproliferative and myelodysplastic/myeloproliferative neoplasms

Myeloproliferative neoplasms (MPN) are a heterogeneous group of hematological disorders presenting with an increased proliferation in one or several hematological cell lines. Renal manifestations of MPN have not been fully characterized so far. To morphologically assess the potential renal involvement in MPN patients, we analyzed histomorphological findings of a post-mortem cohort (n = 57) with a disease history of Philadelphia-negative MPN including polycythaemia vera, primary myelofibrosis, essential thrombocythemia, or chronic myelomonocytic leukemia (CMML). Seven (12.2%) patients presented with a pattern of diffuse glomerulosclerosis not attributable to diabetic or hypertensive nephropathy. Weak C4d staining suggestive for chronic thrombotic microangiopathy (TMA) was observed in 4/7 cases. Glomerulonephritis was excluded by light microscopy and immunohistochemistry. Patients with a pattern of diffuse glomerulosclerosis did not differ from the rest of the cohort regarding MPN subtype, disease duration, age, or sex. No significant proteinuria had been observed before death. Further findings attributed to MPNs were extramedullary hematopoiesis (n = 5; 8.8%) and tumor involvement in advanced disease (n = 4; 7.0%). Other common findings included arteriolosclerosis (n = 18; 31.6%) and signs of shock (n = 8; 14.0%). To our knowledge, this study is so far the largest investigating renal findings in MPN patients. There may be a causal relationship between idiopathic diffuse glomerular sclerosis and MPN, although its clinical significance and pathophysiology remain uncertain with TMA probably being relevant in a subgroup of cases. Our findings demonstrate the spectrum of renal findings in MPN from early to terminal disease of which hematologists should be aware of in daily clinical practice.

Tubulointerstitial nephritis and uveitis syndrome in an adolescent female: a case report

BACKGROUND

Tubulointerstitial nephritis with uveitis syndrome is a rare disease affecting mainly children and young women. Tubulointerstitial nephritis with uveitis is a diagnosis of exclusion, requiring a high degree of clinical suspicion. Studies report recent infections or certain drugs as precipitating factors of a lymphocytic oculorenal immune response. The prognosis is usually favorable with topical and systemic corticosteroid therapy.

CASE PRESENTATION

We report a literature review and the case of a 14-year-old white girl, who presented to the ophthalmology department with features of one-sided uveitis. Upon transfer of patient to nephrological care, diagnostic work-up revealed renal involvement. Renal biopsy showed a mixed-cell and granulomatous tubulointerstitial nephritis with some noncaseating granulomas, leading to a diagnosis of tubulointerstitial nephritis with uveitis syndrome. With topical ocular and systemic corticosteroid therapy, the patients' condition improved over several weeks.

CONCLUSIONS

Our case highlights the importance of early recognition and treatment of this syndrome, where cross-specialty care typically leads to a favorable outcome.

COVID-19-induced acute renal tubular injury associated with elevation of serum inflammatory cytokine

Background

Severe acute respiratory syndrome Coronavirus 2 has rapidly spread worldwide, with acute kidney injury (AKI) as one of the manifestations with unknown causal mechanisms. We aimed to investigate tubular injury by assessing tubular markers and their association with the severity of Coronavirus disease 2019 (COVID-19).

Methods

We examined the associations between laboratory markers and urinary levels of N-acetyl-β-d-glucosaminidase (uNAG), β2-microglobulin (u β2MG), α1-microglobulin (u α1MG), and liver-type fatty acid binding protein (L-FABP). We studied 18 COVID-19 patients without previous chronic kidney disease and analyzed the relationship between the urinary biomarkers and inflammatory markers in patients with severe (n = 7) or non-severe (n = 11) COVID-19, defined by requirements of supplemental oxygen.

Results

Fourteen patients (78%) showed abnormal urinalysis findings and two (11%) developed AKI. Patients with severe COVID-19 had significantly higher levels of proteinuria, uNAG, uβ2MG, uα 1MG, and L-FABP than those with non-severe disease. Serum levels of interleukin-6 (IL-6) were significantly higher on admission in all severe COVID-19 cases and correlated with the levels of L-FABP, uβ2MG, uα1MG, uNAG, and proteinuria. Moreover, the changes in serum IL-6 (ΔIL-6) levels from baseline to 7 days after admission significantly correlated with ΔL-FABP and Δuβ2MG.

Conclusions

Levels of tubular injury markers, especially L-FABP and uβ2MG, were significantly associated with IL-6 levels even in patients with no evident AKI. This suggests that L-FABP and uβ2MG could be useful as early detective biomarkers for COVID-19 associated renal injury.

Minimal Change Disease Following the Pfizer-BioNTech COVID-19 Vaccine

We report on the development of minimal change disease (MCD) with nephrotic syndrome and acute kidney injury (AKI), shortly after first injection of the BNT162b2 COVID-19 vaccine (Pfizer-BioNTech). A 50-year-old previously healthy man was admitted to our hospital following the appearance of peripheral edema. Ten days earlier, he had received the first injection of the vaccine. Four days after injection, he developed lower leg edema, which rapidly progressed to anasarca. On admission, serum creatinine was 2.31 mg/dL and 24-hour urinary protein excretion was 6.9 grams. As kidney function continued to decline over the next days, empirical treatment was initiated with prednisone 80 mg/d. A kidney biopsy was performed and the findings were consistent with MCD. Ten days later, kidney function began to improve, gradually returning to normal. The clinical triad of MCD, nephrotic syndrome, and AKI has been previously described under a variety of circumstances, but not following the Pfizer-BioNTech COVID-19 vaccine. The association between the vaccination and MCD is at this time temporal and by exclusion, and by no means firmly established. We await further reports of similar cases to evaluate the true incidence of this possible vaccine side effect.

An elderly-onset neuroblastoma concomitant with minimal change nephrotic syndrome: the first autopsy case report

BACKGROUND

Neuroblastoma is a well-known embryonal cancer; however, adult-onset neuroblastomas are rare. The systemic symptoms are related to catecholamine excretion or intraabdominal mass effects. Only two cases of neuroblastoma with nephrotic syndrome have previously been reported. We herein present the first autopsy case of neuroblastoma in an older individual associated with minimal change nephrotic syndrome.

CASE PRESENTATION

A 63-year-old man was admitted to our hospital for investigation of general fatigue. His renal function was normal and his urine was negative for protein. A computed tomography scan showed a renal tumor and intraabdominal lymph node swelling. Approximately 4 months after admission, he suddenly developed acute renal failure and severe proteinuria, and hemodialysis was instituted. A computed tomography scan revealed an increase in the size of the renal tumor and lymph nodes. He died 1 month later and an autopsy was performed. The tumor exhibited diffuse proliferation of tumor cells with scant cytoplasm, namely small blue cell tumor with rosette formation. As a result of immunohistochemical study, a neuroblastoma was diagnosed. Despite the patient's severe renal failure, most glomeruli showed no remarkable changes. The tubular epithelium exhibited detachment and vacuolation. Electron microscopic study of the glomeruli showed diffuse effacement of the foot processes. These features indicate a diagnosis of minimal change nephrotic syndrome with acute tubular injury.

CONCLUSIONS

Minimal change nephrotic syndrome is the most common renal manifestation associated with lymphoproliferative malignancies. We here present an extremely rare case of adult-onset neuroblastoma with minimal change nephrotic syndrome.

[COVID-19 and kidney involvement]

Bei einer schweren COVID-19(„coronavirus disease 2019“)-Erkrankung ist neben der Lungenerkrankung das akute Nierenversagen eine der häufigsten und schwerwiegendsten Komplikationen. SARS-CoV‑2 („severe acute respiratory syndrome coronavirus 2“) konnte auch in der Niere nachgewiesen werden. Patienten mit chronischen Nierenerkrankungen und an der Dialyse wie auch nierentransplantierte Patienten scheinen eine besonders vulnerable Population darzustellen. Die zunehmende Anzahl SARS-CoV-2-infizierter Patienten hat das Interesse an der genauen Pathophysiologie und Morphologie der Nierenschädigung sowie am direkten Virusnachweis in der Niere geweckt, der im Gegensatz zur Lunge insgesamt schwieriger zu führen ist. Hierzu liegen mittlerweile Daten aus größeren Autopsie- und Nierenbiopsiestudien vor. Während der Nachweis von SARS-CoV-2-RNA im Gewebe zu gut reproduzierbaren Ergebnissen führt, wird insbesondere der Virusnachweis mittels Elektronenmikroskopie aufgrund zahlreicher Artefakte kritisch diskutiert. Die genauen und direkten Effekte von SARS-CoV‑2 auf die Niere sind noch nicht im Detail bekannt und derzeit im Fokus intensiver Forschung.

Experimental rat model for acute tubular injury induced by high water hardness and high water fluoride: efficacy of primary preventive intervention by distilled water administration

Background

High water hardness associated with high water fluoride and the geographical distribution of Chronic Kidney Disease of unknown etiology (CKDu) in Sri Lanka are well correlated. We undertook this study to observe the effects of high water hardness with high fluoride on kidney and liver in rats and efficacy of distilled water in reducing the effects.

Methods

Test water sample with high water hardness and high fluoride was collected from Mihinthale region and normal water samples were collected from Kandy region. Twenty-four rats were randomly divided into 8 groups and water samples were introduced as follows as daily water supply. Four groups received normal water for 60 (N1) and 90 (N2) days and test water for 60 (T1) and 90 (T2) days. Other four groups received normal (N3) and test (T3) water for 60 days and followed by distilled water for additional 60 days and normal (N4) and test (T4) water for 90 days followed by distilled water for another 90 days. The rats were sacrificed following treatment. Serum samples were subjected to biochemical tests; serum creatinine, urea, aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP) and elemental analysis. Histopathological examinations were carried out using kidney and liver samples.

Results

Test water treated groups were associated with acute tubular injury with loss of brush border and test water followed with distilled water treated groups maintained a better morphology with minimal loss of brush border. Serum creatinine levels in T1 and T2 groups and urea level in T2 group were significantly (p < 0.05) increased compared to control groups. After administration of distilled water, both parameters were significantly reduced in T4 group (p < 0.05) compared to T2. Serum AST activity was increased in T4 group (p < 0.05) compared to control group with no histopathological changes in liver tissues. The serum sodium levels were found to be much higher compared to the other electrolytes in test groups.

Conclusion

Hard water with high fluoride content resulted in acute tubular injury with a significant increase in serum levels of creatinine, urea and AST activity. These alterations were minimized by administering distilled water.

Hemophagocytic syndrome with acute kidney injury accompanied by erythrophagocytic macrophages in the tubular lumen

Hemophagocytic syndrome (HPS) is a life-threatening syndrome involving excessive immune activation. It is often accompanied by renal involvement known as acute kidney injury (AKI), which is a poor prognostic factor of HPS. Thus, early diagnosis and treatment are very important. However, it is rarely identified in renal biopsy specimens, and its major manifestation is acute tubular necrosis. We report a rare case of erythrophagocytic macrophage presence in the tubular lumen of a patient with HPS-associated AKI. A kidney biopsy showed acute tubular necrosis, interstitial massive macrophage infiltration, and phagocytic macrophage casts without glomerular change. Some arteriolar vascular smooth muscle cells showed vacuolization because they were positive for α-smooth muscle actin. The patient's renal function improved after methylprednisolone pulse therapy followed by oral prednisolone after a month. Our case presents a new pathologic pattern of HPS. Careful urinalysis could suggest renal involvement with HPS. Having knowledge of this pathologic pattern of HPS is important to recognize the disease and to treat it appropriately.

Acute kidney injury and disseminated intravascular coagulation due to mercuric chloride poisoning

Mercury is a toxic heavy metal and occurs in organic and inorganic forms. Inorganic mercury includes elemental mercury and mercury salts. Mercury salts are usually white powder or crystals, and widely used in indigenous medicines and folk remedies in Asia. Inorganic mercury poisoning causes acute kidney injury (AKI) and gastrointestinal manifestations and can be life-threatening. We describe a case with unknown substance poisoning who developed AKI and disseminated intravascular coagulation (DIC). Renal biopsy showed acute tubular necrosis. Later, the consumed substance was proven to be mercuric chloride. His renal failure improved over time, and his creatinine normalized after 2 months.

Urinary liver-type fatty acid-binding protein linked with increased risk of acute kidney injury after allogeneic stem cell transplantation

Stem cell transplantation (SCT) involves a great risk of acute kidney injury (AKI). Urinary liver-type fatty acid-binding protein (uL-FABP) is a sensitive biomarker to detect kidney damage before an increase in serum creatinine (Cr); however, the utility of uL-FABP is not fully understood in the platform of SCT. A prospective study was conducted in 84 allogeneic SCT recipients to ascertain a link between the uL-FABP level before preparative procedures and AKI incidence after SCT. The association between them was analyzed using Gray's method and a multivariate Fine-Gray proportional hazards regression model. The recipients were stratified into high and low uL-FABP groups, according to the reference value for healthy subjects (8.4 μg/g Cr). AKI developed more frequently in the high (n = 20) than low (n = 64) group (55.0% versus 26.6% at day 30, P = .005), and high uL-FABP was an independent risk for the emergence of AKI (hazard ratio, 2.78; 95% confidence interval, 1.24 to 6.22, P = .01). In conclusion, increased baseline uL-FABP, which may indicate previous incipient kidney injury, is linked with a high risk of AKI after allogeneic SCT.

Clinicopathological spectrum of kidney diseases in cancer patients treated with vascular endothelial growth factor inhibitors: a report of 5 cases and review of literature

Recently, cancer therapies have been supplemented by vascular endothelial growth factor (VEGF) inhibitors as anti-angiogenic agents. However, kidney-related adverse reactions associated with these agents clinically manifest as hypertension and proteinuria, the most severe form being thrombotic microangiopathy (TMA). We present the spectrum of pathological features in VEGF inhibitor-associated kidney disease. Clinicopathological findings of kidney disease were retrospectively studied in 5 cancer patients treated with anti-VEGF agents. Although 4 cases received bevacizumab (anti-VEGF-A), one was given sorafenib (small molecule tyrosine kinase inhibitor affecting VEGF-R2). All patients presented with acute kidney injury, hypertension, and/or proteinuria. All kidney biopsies showed recent and chronic endothelial injury of varying severity and vascular sclerosis, including 2 with typical active features of TMA. Furthermore, acute tubular injury with focal necrosis was seen in all cases. While administration of VEGF inhibitor was discontinued in 4 cases, it was resumed for 5 more doses, following steroid therapy in 1 case. Cessation of VEGF inhibitor therapy was successful in reversing anemia and led to improvement of hypertension and proteinuria in 4 of the 5 cases. One case with TMA progressed to end-stage renal disease. A range of renal pathologic lesions secondary to endothelial injury are noted often accompanied by acute tubular damage following anti-VEGF therapy, the most severe being TMA. While most of the clinical manifestations are reversible with discontinuation of therapy, the role of other nephrotoxic chemotherapeutic agents in enhancing renal injury including severe TMA and other host factors with possible poor outcome should be considered.