Angiomyolipoma With Epithelial Cysts: A Rare but Distinct Variant of Angiomyolipoma

Renal angiomyolipomas, common benign tumors, can exhibit slow growth in sporadic cases or have aggressive tendencies when linked to genetic conditions like tuberous sclerosis. This case report focuses on the exceptionally rare angiomyolipoma with epithelial cysts (AMLEC) variant, particularly challenging to diagnose due to its scarcity. Describing a 41-year-old woman's case, initially suspected to be renal cell carcinoma during an infertility evaluation, subsequent partial nephrectomy revealed a tumor comprising smooth muscle, blood vessels, and fat, with cystic regions featuring cuboidal linings and a layer devoid of abnormal cell activity. Immunohistochemistry confirmed specific markers within different tumor components, highlighting the diagnostic complexities of AMLEC and emphasizing the crucial role of histopathological examinations in accurate characterizations.

Expanding Role of Dual-Energy CT for Genitourinary Tract Assessment in the Emergency Department, From the AJR Special Series on Emergency Radiology

Among explored applications of dual-energy CT (DECT) in the abdomen and pelvis, the genitourinary (GU) tract represents an area where accumulated evidence has established the role of DECT to provide useful information that may change management. This review discusses established applications of DECT for GU tract assessment in the emergency department (ED) setting, including characterization of renal stones, evaluation of traumatic injuries and hemorrhage, and characterization of incidental renal and adrenal findings. Use of DECT for such applications can reduce the need for additional multiphase CT or MRI examinations and reduce follow-up imaging recommendations. Emerging applications are also highlighted, including use of low-energy virtual monoenergetic images (VMIs) to improve image quality and potentially reduce contrast media doses and use of high-energy VMIs to mitigate renal mass pseudoenhancement. Finally, implementation of DECT into busy ED radiology practices is presented, weighing the trade-off of additional image acquisition, processing time, and interpretation time against potential additional useful clinical information. Automatic generation of DECT-derived images with direct PACS transfer can facilitate radiologists' adoption of DECT in busy ED environments and minimize impact on interpretation times. Using the described approaches, radiologists can apply DECT technology to improve the quality and efficiency of care in the ED.

Approach to Kidney Biopsy: Core Curriculum 2022

The kidney biopsy is an essential tool for diagnosis of many kidney diseases. Obtaining an adequate biopsy sample with appropriate allocation for various studies is essential. Nephrologists should understand key lesions and their interpretation because these are essential elements underlying optimal approaches for interventions. This installment in the AJKD Core Curriculum in Nephrology will review these topics. We will first briefly discuss considerations for allocation and processing of kidney biopsies. We will then present in outline form the differential diagnoses of a spectrum of patterns of injury and consideration for interpretation of specific lesions. Lesions are presented according to anatomic site as glomerular, vascular, or tubulointerstitial. Native and transplant kidney biopsy lesions are included. These lesions and differential diagnoses and specific diseases are then linked to detailed clinicopathologic discussion of specific diseases presented in the AJKD Atlas of Kidney Pathology II. Correlation with immunofluorescence, electron microscopy, and clinical findings are emphasized to reach a differential diagnosis and the final diagnosis.

Contact surface area and its association with outcomes in robotic-assisted partial nephrectomy

BACKGROUND

Renal tumor scoring systems, such as the contact surface area value, aim to assist in predicting outcomes following robotic-assisted partial nephrectomy. The aim of this study is to identify associations between specific postoperative outcomes and the contact surface area of renal masses.

METHODS

We analyzed 332 consecutive robotic-assisted partial nephrectomies and calculated contact surface area for renal tumors with the contact surface area formula (CSA = 2πrd), where π ≈ 3.14, r = greatest tumor radius (cm), and d = greatest tumor depth (cm).

RESULTS

Higher contact surface area was associated with longer warm ischemia time (P < .001), higher estimated blood loss (P < .001), and longer length of hospital stay (LOS) (P < .001). Higher contact surface area was significantly associated with decreased renal function at 1 day, 1 month, and 6 months following robotic-assisted partial nephrectomy.

CONCLUSIONS

Contact surface area is associated with certain outcomes following robotic-assisted partial nephrectomy and may be a useful predictive tool.

Collapsing Lesions and Focal Segmental Glomerulosclerosis in Pregnancy: A Report of 3 Cases

The relationship between focal segmental glomerulosclerosis (FSGS) and pregnancy is complex and not completely elucidated. Pregnancy in patients with FSGS poses a high risk for complications, possibly due to hemodynamic factors, imbalance between angiogenic and antiangiogenic factors, and hormonal conditioning. Although poor clinical outcomes associated with collapsing FSGS are common outside of pregnancy, the prognosis during pregnancy is not well documented. We report 3 patients who developed collapsing FSGS during pregnancy, 2 of whom had presumed underlying FSGS. Two patients underwent biopsy during pregnancy, and 1, during the puerperium. None of the 3 patients improved spontaneously after delivery, and 1 experienced a rapid deterioration in kidney function and proteinuria after delivery. Aggressive immunosuppressive therapy led to a full response in 1 case (without chronic lesions) and to partial responses in the remaining 2 cases. These cases suggest that collapsing lesions should be considered in patients with FSGS who develop a rapid increase in serum creatinine level or proteinuria during pregnancy and that these lesions may at least partially respond to treatment.

Comparison of Iodine Quantification and Conventional Attenuation Measurements for Differentiating Small, Truly Enhancing Renal Masses From High-Attenuation Nonenhancing Renal Lesions With Dual-Energy CT

OBJECTIVE. The purpose of this study is to determine whether iodine quantification techniques from contrast-enhanced dual-energy CT (DECT) data allow equal differentiation of small enhancing renal masses from high-attenuation (> 20 HU of unenhanced attenuation) nonenhancing lesions, compared with conventional attenuation measurements. MATERIALS AND METHODS. A total of 220 nonconsecutive patients (mean [± SD] age, 66 ± 13 years; 130 men and 90 women) with 265 high-attenuation renal lesions (mean attenuation, 54 ± 33 HU; 91 enhancing lesions) were included. Each patient underwent single-energy unenhanced CT followed by DECT during the nephrographic phase using one of four different high-end DECT platforms (first- and second-generation rapid-kilovoltage-switching DECT platforms and second- and third-generation dual-source DECT platforms). Iodine quantification measurements and conventional attenuation change measurements were calculated for each lesion. Diagnostic accuracy was determined by pathologic analysis, confirmation with another imaging modality, or greater than 24 months of imaging follow-up as the reference standard. RESULTS. The diagnostic accuracy for differentiating enhancing from nonenhancing renal lesions was significantly higher for conventional attenuation change measurements, compared with iodine quantification measurements (AUC values, 0.973 vs 0.875; p < 0.0001). The diagnostic performance of iodine quantification measurements improved only marginally with the utilization of DECT platform-specific optimized iodine quantification thresholds, yielding AUC values of 0.907 and 0.893 for the rapid-kilovoltage-switching DECT and dual-source DECT platforms, respectively. Unenhanced lesion attenuation (p = 0.0010) and intraparenchymal location (p = 0.0249) significantly influenced the diagnostic accuracy of the iodine quantification techniques. CONCLUSION. Iodine quantification from DECT data yields inferior diagnostic accuracy when compared with conventional attenuation change measurements for differentiating small, truly enhancing renal masses and high-attenuation renal lesions.

[Morphological verification of renal lesion as a compulsory stage in the diagnosis of Fabry disease]

The paper describes a case of Fabry disease in a patient in whom kidney biopsy enabled the renal lesion be characterized in detail. Fabry nephropathy-associated kidney tissue changes, including renal lesion, have been verified using electron microscopy of renal tissue.