Adult-onset Krabbe disease presenting as isolated sensorimotor demyelinating polyneuropathy: A case report.

Krabbe disease is a rare autosomal recessive neurodegenerative disease, caused by mutations in the GALC gene, which encodes for the lysosomal enzyme galactocerebrosidase. Typical clinical manifestations of Krabbe include psychomotor deterioration, visual loss, seizures, and spasticity, that result from central nervous system demyelination. We report a case of a 35-year-old male with Krabbe who presented in adulthood with isolated severe, upper extremity predominant demyelinating sensorimotor polyneuropathy and did not develop other distinguishing clinical or radiological features of Krabbe until the later stages of the disease. The patient's diagnostic odyssey lasted 13 years from presentation to diagnosis, which was ultimately determined with the use of whole exome sequencing (WES) at the age of 48 years. The expanding phenotypic spectrum of adult-onset Krabbe Disease (AOKD) presents a diagnostic challenge that can lead to diagnostic delays and potentially affect treatment options. Our patient's case underscores the importance of pursuing WES in those with undiagnosed progressive neuromuscular disorders.

Natural history of simple renal cysts: longitudinal CT-based evaluation.

PURPOSE: Simple renal cysts are common benign lesions that arise from the renal parenchyma. Cyst growth can lead to confusion as well as concern from patients and referring providers about the need for imaging follow-up or additional evaluation. The purpose of this study was to evaluate the natural history of simple renal cysts and determine the best metric to characterize cyst evolution. METHODS: 222 simple renal cysts in 182 adults (age = 58.4 ± 6.0 years) were longitudinally evaluated on non-contrast CT examinations over a mean interval of 7.5 ± 2.8 years. Axial long axis, surface area, and volume were evaluated at baseline and follow-up CT examinations. Absolute and percent annualized growth rates were computed between CT studies for each parameter. RESULTS: At baseline CT examinations, mean (± SD) axial long axis, surface area, and volume measurements were 2.5 ± 1.7 cm, 2.5 ± 4.5 cm2, and 17.6 ± 52.5 ml, respectively. On follow-up examinations, measurements were 3.4 ± 2.0 cm, 4.2 ± 5.9 cm2, and 34.4 ± 92.3 ml, respectively. Significant differences (p < 0.01) were found between baseline and follow-up values for each parameter. The absolute growth rate of each parameter was + 0.1 ± 0.1 cm/year, + 2.1 ± 3.4 cm2/year, and + 2.0 ± 5.6 ml/year, respectively. The percent annualized growth rate for each parameter was +6.5 ± 7.3%/year, +18 ± 24%/year, and +46 ± 100%/year, respectively. Overall, 86% (190/222) of cysts increased in size over time; most notably 78% (174/222) increased by ≥ 6% in volume per year. None of the simple cysts developed septations or solid components on follow-up examinations. CONCLUSION: The majority of simple renal cysts increase in size over time, which was not associated with the development of complex features. Surface area and volume are the parameters most indicative of cyst growth or regression over time. In patients with enlarging asymptomatic simple renal cysts, no follow-up imaging is indicated.

Comparison of CT Texture Analysis Software Platforms in Renal Cell Carcinoma: Reproducibility of Numerical Values and Association With Histologic Subtype Across Platforms.

OBJECTIVE. The purpose of this article is to evaluate interobserver, intraobserver, and interplatform variability and compare the previously established association between texture metrics and tumor histologic subtype using three commercially available CT texture analysis (CTTA) software platforms on the same dataset of large (> 7 cm) renal cell carcinomas (RCCs). MATERIALS AND METHODS. CT-based texture analysis was performed on contrast-enhanced MDCT images of large (> 7 cm) untreated RCCs in 124 patients (median age, 62 years; 82 men and 42 women) using three different software platforms. Using this previously studied cohort, texture features were compared across platforms. Features were correlated with histologic subtype, and strength of association was compared between platforms. Single-slice and volumetric measures from one platform were compared. Values for interobserver and intraobserver variability on a tumor subset (n = 30) were assessed across platforms. RESULTS. Metrics including mean gray-level intensity, SD, and volume correlated fairly well across platforms (concordance correlation coefficient [CCC], 0.66-0.99; mean relative difference [MRD], 0.17-5.97%). Entropy showed high variability (CCC, 0.04; MRD, 44.5%). Mean, SD, mean of positive pixels (MPP), and entropy were associated with clear cell histologic subtype on almost all platforms (p < .05). Mean, SD, entropy, and MPP were highly reproducible on most platforms on both interobserver and intraobserver analysis. CONCLUSION. Select texture metrics were reproducible across platforms and readers, but other metrics were widely variable. If clinical models are developed that use CTTA for medical decision making, these differences in reproducibility of some features across platforms need to be considered, and standardization is critical for more widespread adaptation and implementation.

Utility of CT Texture Analysis in Differentiating Low-Attenuation Renal Cell Carcinoma From Cysts: A Bi-Institutional Retrospective Study.

OBJECTIVE. The purpose of this study was to evaluate the utility of CT texture analysis (CTTA) in differentiating low-attenuation renal cell carcinoma (RCC) from renal cysts on unenhanced CT. MATERIALS AND METHODS. Ninety-four patients with low-attenuation RCC on unenhanced CT were compared with a cohort of 192 patients with benign renal cysts. CT characteristics (size and minimum, maximum, and mean attenuation) and CTTA features were recorded using an ROI approximately two-thirds the size of the mass. Masses were subjectively assessed by two expert genitourinary readers and two novice readers using a 5-point Likert scale (1 = definite cyst, 5 = definite renal cell carcinoma). Results of first-order CTTA and subjective evaluation were compared using ROC analysis. RESULTS. The group of 94 patients with low-attenuation RCC included 62 men and 32 women (mean age, 58.0 years). On unenhanced CT, the RCC were larger than 10 mm and of a median size of 50 mm with less than or equal to 20 HU (mean attenuation, 16 ± 4 HU). Of the RCC cohort, 83 were clear cell subtype. The cohort of 192 patients included 134 men and 58 women (mean age, 64.7 years) with benign renal cysts greater than 10 mm and a median size of 27 mm and less than or equal to 20 HU (mean attenuation, 9 ± 6 HU). The mean follow-up time was 6.2 years. Mean entropy in the low-attenuation RCC group (4.1 ± 0.7) was significantly higher than in the cyst group (2.8 ± 1.3, p < 0.0001). Entropy showed an ROC AUC of 0.89, with sensitivity of 84% and specificity of 80% at threshold 3.9. The AUC was better than subjective evaluation by novice readers (AUC, 0.77) and comparable to subjective evaluation by two expert readers (AUC, 0.90). A model combining the three best texture features (unfiltered mean gray-level attenuation, coarse entropy, and kurtosis) showed an improved AUC of 0.92. CONCLUSION. High entropy revealed with CTTA may be used to differentiate low-attenuation RCC from cysts at unenhanced CT; this technique performs as well as expert readers.