Person:

Shinagare, Atul

Background: The aim of the study was to analyze the clinical and imaging characteristics of primary intrathoracic malignant peripheral nerve sheath tumors (MPNSTs). Patients and methods. In this institutional review board (IRB)-approved retrospective study, clinical and imaging features of 15 patients (eight men; mean age 50 years [range 18–83)] with pathologically proven malignant peripheral nerve sheath tumors seen from January 1999 to December 2011 were analyzed. Imaging features (CT in 15, MRI in 5 and PET/CT in 4) of primary tumors were evaluated by three radiologists and correlated with clinical management. Results: Of the 15 tumors, six were located in the mediastinum (two each in anterior, middle and posterior mediastinum), four in chest wall, two were paraspinal, and three in the lung. Four patients had neurofibromatosis-1 (NF1); four tumors had heterologous rhabdomyoblastic differentiation (malignant triton tumor). Masses typically were elongated along the direction of nerves, with mean size of 11 cm. The masses were hypo- or isodense to muscles on CT, isointense on T1-weighted images, hyperintense on T2-weighted images and intensely fluorodeoxyglucose (FDG) avid (mean standardized uptake value [SUV]max of 10.5 [range 4.4–23.6]). Necrosis and calcification was seen in four tumors each. Finding of invasion of adjacent structures on imaging led to change in management in seven patients; patients with invasion received chemoradiation. Conclusions: Intrathoracic MPNSTs appear as large elongated masses involving mediastinum, lung or chest wall. Radiological identification of invasion of adjacent structures is crucial and alters therapy, with patients with invasion receiving neoadjuvant or adjuvant chemoradiation.

Purpose: Clear cell tubulopapillary renal cell carcinoma (CCTPRCC) is a recently described, low grade subtype of renal cancer. We determined if imaging features could be used to distinguish early-stage CCTPRCC from stage-matched clear cell RCC (ccRCC) and papillary RCC (pRCC). Subjects and Methods: This IRB-approved retrospective study included 54 stage-Ia patients with pathologically-confirmed CCTPRCC (n=18), ccRCC (n=18), and pRCC (n=18). CT (n=48) and MRI (n=27) exams were reviewed and imaging features compared. Continuous variables were evaluated using ANOVA and Tukey's multiple comparison tests. Categorical variables were compared using Chi square test or Fisher's exact test. Results: Compared to pRCC, CCTPRCC had a lower mean attenuation value on unenhanced CT (p<0.017), was more often hyperintense on T2-weighted images (p<0.0001), showed an ill-defined margin (p=0.003), and demonstrated nonenhancing areas (p=0.0003). The presence of all three of these statistically significant features (hypoattenuation [unenhanced attenuation < 25HU], ill-defined margin, nonenhancing areas) yielded an area under the Receiver Operator Curve (ROC) of 0.92 (95% CI: 0.83-0.99) for differentiating CCTPRCC from pRCC. There were no significant differences in the imaging features of CCTPRCC and ccRCC. Conclusions: Early stage clear cell tubulopapillary renal cell carcinoma can be distinguished from papillary RCC based on low attenuation on unenhanced CT, high intensity on T2-weighted images, an ill-defined margin, and presence of nonenhancing areas, but cannot be distinguished from clear cell RCC.

Background: The aim of the study was to evaluate the clinical and imaging features of extraskeletal myxoid chondrosarcoma (EMC) including initial presentation, recurrence, and metastases. Patients and methods. In this institutional review board-approved retrospective study, imaging features of 13 patients with pathologically proven EMC seen from August 1995 to December 2011 were analyzed. The group included 3 women and 10 men and the mean age was 54 years (range 29–73 years). Imaging studies were evaluated by two radiologists in consensus. Location, size, and imaging features of primary tumors were recorded as well as the presence of recurrent disease and location of metastases. Results: Among 13 patients, 3 died during the timeframe of this study. Nine patients had primary tumor in the lower extremity, and average tumor size was 9.3 cm (range 3.3–18 cm). On MRI, primary tumors were hyperintense on T2, isointense to muscle on T1, and demonstrated peripheral/septal enhancement. Three patients had local recurrence and 12 had metastatic disease, with lung involvement being the most common. Tumor density on contrast enhanced CT ranged from 8.2 to 82.9 Hounsfield unit (HU). FDG-PET/CT imaging was performed in 3 patients. One patient had no FDG avid disease and 2 patients had metastatic disease with standard uptake values (SUV) of 2.8 and 7.4. The patient with intense FDG uptake demonstrated more solid appearing tumor burden and had the shortest survival. Conclusions: EMC is a rare tumor that often occurs in the lower extremities and frequently metastasizes to the lungs. Increased tumor density and increased FDG uptake may be related to more aggressive disease.

Purpose: To investigate associations between imaging features and mutational status of clear cell renal cell carcinoma (ccRCC). Materials and methods: This multi-institutional, multi-reader study included 103 patients (77 men; median age 59 years, range 34–79) with ccRCC examined with CT in 81 patients, MRI in 19, and both CT and MRI in three; images were downloaded from The Cancer Imaging Archive, an NCI-funded project for genome-mapping and analyses. Imaging features [size (mm), margin (well-defined or ill-defined), composition (solid or cystic), necrosis (for solid tumors: 0%, 1%–33%, 34%–66% or >66%), growth pattern (endophytic, <50% exophytic, or ≥50% exophytic), and calcification (present, absent, or indeterminate)] were reviewed independently by three readers blinded to mutational data. The association of imaging features with mutational status (VHL, BAP1, PBRM1, SETD2, KDM5C, and MUC4) was assessed. Results: Median tumor size was 49 mm (range 14–162 mm), 73 (71%) tumors had well-defined margins, 98 (95%) tumors were solid, 95 (92%) showed presence of necrosis, 46 (45%) had ≥50% exophytic component, and 18 (19.8%) had calcification. VHL (n = 52) and PBRM1 (n = 24) were the most common mutations. BAP1 mutation was associated with ill-defined margin and presence of calcification (p = 0.02 and 0.002, respectively, Pearson’s χ2 test); MUC4 mutation was associated with an exophytic growth pattern (p = 0.002, Mann–Whitney U test). Conclusions: BAP1 mutation was associated with ill-defined tumor margins and presence of calcification; MUC4 mutation was associated with exophytic growth. Given the known prognostic implications of BAP1 and MUC4 mutations, these results support using radiogenomics to aid in prognostication and management.

Aim: To assess if CT texture analysis (TA) can serve as a biomarker of liver toxicity in patients with colorectal cancer treated with 5-fluorouracil (5-FU)-based chemotherapy. Materials and methods: In this IRB-approved, HIPAA-compliant retrospective study, patients with colorectal cancer treated with 5-FU-based regimens during 2008-2010 were identified from institutional electronic database. Total 43 patients (23 women; mean age 56 years) with normal baseline liver function tests (LFTs), availability of baseline (pre-chemotherapy) and first follow-up CT (median 1.7 months, interquartile range (IQR):1.5-2.5) performed during chemotherapy were included. Two single-slice ROI of right and left liver lobe were obtained on baseline and first follow-up CT for TA. Texture features (mean, entropy, kurtosis, skewness, mean of positive pixel, standard deviation (SD)) were extracted using a commercially available software (TexRAD; Feedback Medical Ltd, Cambridge, UK). Changes in texture parameters between baseline and follow-up CT were evaluated with Wilcoxon signed-rank test for patients with and without LFT elevation during chemotherapy. Results: Patients with LFT elevation (n=34;79%) showed significantly different mean, entropy and SD (p-values range: 0.01-0.05) between baseline and first follow-up CT. No significant changes in features were observed in patients without LFT elevation (n=9;21%). In 19 patients (56%), first follow-up CT was performed before elevation of LFTs was observed. Conclusions: This proof-of-concept study shows that there are early changes in liver texture on first follow-up CT in patients with LFT elevation during 5-FU-based chemotherapy for colorectal cancer. In more than 50% of cases, these changes occur before LFT elevation becomes evident on blood tests.

Objective: To describe metastatic pattern of uterine leiomyosarcomas (ULMS) and correlate it with clinical and histopathologic parameters. Methods: We included 113 women (mean age, 53 years; range, 29 to 72 years) with histopathology-confirmed ULMS from 2000 to 2012. Distribution of metastases was noted from imaging by two radiologists in consensus. Predictors of development of metastases were analyzed with univariate and multivariate analysis. Impact of various clinical and histopathologic parameters on survival was compared using Log-rank test and Cox proportional hazard regression model. Results: Distant metastases were seen in 81.4% (92/113) of the patients after median interval of 7 months (interquartile range, 1 to 21). Lung was most common site of metastases (74%) followed by peritoneum (41%), bones (33%), and liver (27%). Local tumor recurrence was noted in 57 patients (50%), 51 of whom had distant metastases. Statistically significant correlation was noted between local recurrence and peritoneal metastases (p<0.001) and between lung and other common sites of hematogeneous metastases (p<0.05). Age, serosal involvement, local recurrence, and the International Federation of Gynecology and Obstetrics (FIGO) stage were predictive factors for metastases. At the time of reporting, 65% (74/113) of the patients have died; median survival was 45 months. Stage, local recurrence, and age were poor prognostic factors. Conclusion: ULMS metastasizes most frequently to lung, peritoneum, bone, and liver. Local recurrence was associated with peritoneal spread and lung metastases with other sites of hematogeneous metastases. Age, FIGO stage and local recurrence predicted metastatic disease and advanced stage, older age and local recurrence predicted poor outcome.