Specific computed tomography imaging characteristics of congenital mesoblastic nephroma and correlation with ultrasound and pathology

Using imaging to diagnose renal tumors beyond nephroblastoma

Wilm's tumor (WT) accounted for the vast majority of renal tumors in children (92%). However, there are many atypical or rare forms of kidney cancer, and it is certainly useful to have a diagnostic orientation in imaging to differentiate between the different diagnoses, guiding that way the therapeutic management. We report the cases of 3 patients who were initially diagnosed with nephroblastoma on the basis of radiological data (via PACS search), underwent pre-operative chemotherapy and then nephrectomy, and whose anatomopathological evidence came back in favor of benign renal tumors. Nephroblastoma is the most common renal tumor in children, but other benign tumors should not be neglected, radiological signs that may point to this entity should be taken into account, so that neoadjuvant chemotherapy with its enfeebling side effects can be avoided.

A Novel, Simple, and Low-Cost Approach for Machine Learning Screening of Kidney Cancer: An Eight-Indicator Blood Test Panel with Predictive Value for Early Diagnosis

Clear cell renal cell carcinoma (ccRCC) accounts for more than 90% of all renal cancers. The five-year survival rate of early-stage (TNM 1) ccRCC reaches 96%, while the advanced-stage (TNM 4) is only 23%. Therefore, early screening of patients with renal cancer is essential for the treatment of renal cancer and the long-term survival of patients. In this study, blood samples of patients were collected and a pre-defined set of blood indicators were measured. A random forest (RF) model was established to predict based on each indicator in the blood, and was trained with all relevant indicators for comprehensive predictions. In our study, we found that there was a high statistical significance (p < 0.001) for all indicators of healthy individuals and early cancer patients, except for uric acid (UA). At the same time, ccRCC also presented great differences in most blood indicators between males and females. In addition, patients with ccRCC had a higher probability of developing a low ratio of albumin (ALB) to globulin (GLB) (AGR < 1.2). Eight key indicators were used to classify and predict renal cell carcinoma. The area under the receiver operating characteristic (ROC) curve (AUC) of the eight-indicator model was as high as 0.932, the sensitivity was 88.2%, and the specificity was 86.3%, which are acceptable in many applications, thus realising early screening for renal cancer by blood indicators in a simple blood-draw physical examination. Furthermore, the composite indicator prediction method described in our study can be applied to other clinical conditions or diseases, where multiple blood indicators may be key to enhancing the diagnostic potential of screening strategies.

Benign Renal Tumors in Pediatric Age Group: Retrospective Analysis

Background:

Benign renal tumors are extremely rare and were studied here. This series also includes a renal teratoma in a horseshoe kidney, probably only the second in the pediatric literature.

Materials and Methods:

Retrospective review of children with benign renal tumors operated between 2006 and 2018 at one center.

Results:

Twelve patients (M:F ratio 10:2), age range 3 weeks (31-week gestation) to 13 years presented with large palpable renal swelling (n = 12) and hematuria (n = 3). Computed tomography (CT) scan showed features typical of the tumor. Final histopathology (age group [mean]) showed: multilocular cystic nephroma (MLCN) - n = 5 (41.7%), (11–16 months [13.6]); congenital mesoblastic nephroma (CMN) - n = 4 (33.3%) (classic 1, cellular 3) (0.75–5 months [2.125]); mature cystic teratoma - n = 1 (8.3%): (48 months, in a horseshoe kidney), and angiomyolipoma (AML) - n = 2 (16.7%) (144 months [sporadic] and 156 months [tuberous sclerosis]) One patient with cystic teratoma with no calcification on CT scan received pre-operative chemotherapy as fine-needle aspiration cytology (FNAC) reported malignant small blue cell tumor. Nephroureterectomy with Gerota's fascia could be done easily in all without intraoperative complications. Delay in presentation in MLCN and CMN led to increased symptoms and CT scan changes. All patients did well in 1.5–12 years (median 3 years) follow-up including cellular mesoblastic nephroma.

Conclusions:

Benign renal tumors often occur in specific age groups but may overlap that of Wilms tumor. Proper interpretation of clinical presentation, CT scan, and FNAC findings help in avoiding preoperative chemotherapy. Upfront nephroureterectomy is curative. Histopathological findings decide further treatment. Children with AML and tuberous sclerosis need lifelong follow-up.

[Imaging of renal tumors in children]

CLINICAL/METHODOLOGICAL ISSUE

Renal tumors in children are treated according to the guidelines of the Renal Tumor Study Group of the International Society of Pediatric Oncology (SIOP-RTSG). Nephroblastoma is the most frequent renal tumor in children.

STANDARD RADIOLOGICAL METHODS

After sonography, magnetic resonance imaging (MRI) is the preferred imaging modality. The task of imaging includes differential diagnosis with the help of morphological and epidemiological criteria. Thorax computed tomography (CT) is introduced for initial staging.

METHODOLOGICAL INNOVATIONS

Current studies of diffusion-weighted imaging (DWI)-MRI with analysis of the apparent diffusion coefficient (ADC) histogram indicate the potential to differentiate blastemal or anaplastic high-risk histology nephroblatoma subtypes. Imaging criteria for nephron-sparing surgery are defined and allow an individual therapy option in unilateral and especially in bilateral renal nephroblastoma.

PERFORMANCE

In addition to nephroblastoma, the differential diagnosis includes congenital mesoblastic nephroma, malignant rhabdoid tumor of the kidney, clear cell sarcoma and renal cell carcinoma. The diagnosis of nephrogenic rests and nephroblastomatosis is challenging.

ACHIEVEMENTS

Diagnostic standardization improves diagnosis and therapy of renal childhood tumors, and new prognostic markers may be introduced in the near future.

Imaging manifestations of congenital mesoblastic nephroma

OBJECTIVE

Congenital mesoblastic nephroma (CMN) is a rare renal tumor mainly observed in infants and young children. This study aims to analyze the imaging manifestations of CMN to improve the understanding of the disease.

METHODS

The imaging manifestations and clinical records of all pediatric patients with CMN admitted to our hospital over the last 7 years were retrospectively analyzed. The diagnosis of CMN was confirmed by postoperative pathology. All patients underwent computed tomography (CT) scans; 2 patients additionally underwent magnetic resonance imaging (MRI) scans (including one prenatal MRI scan).

RESULTS

We evaluated 10 pediatric patients (6 males and 4 females) aged 7 days to 12 months (median age: 4 months) with CMN located on the left kidney in six cases and the right kidney in four cases. The CT imaging manifested as solid lesions (5 cases), solid-cystic lesions with solid predominance (4 cases), or solid-multicystic lesions with cystic predominance (1 case). Enhanced CT showed moderately and heterogeneously enhanced solid component and intracystic septations at the corticomedullary phase that were further enhanced at the nephrographic phase, although their CT values were still lower than those of the renal parenchyma. The "double-layer sign" were seen in 4 cases of classic type of CMN, and the "intratumor pelvis sign" were seen in 9 cases that include 5 classic, 3 cellular and 1 mixed type of CMN. In the 2 patients who underwent MRI, the scans showed solitary masses. The lesions had hypointense signals on the T1WI sequence and isointensity or slightly lower-intensity signals than the surrounding renal parenchyma on the fluid-sensitive sequences, whereas the lesions showed hyperintense signals on the diffusion-weighted imaging (DWI) sequence.

CONCLUSIONS

The imaging manifestations of CMN are closely correlated with the pathological subtype and have certain characteristics. The "double-layer sign" was seen with most classic type CMN, and "intratumor pelvis sign" was seen in 90% cases.