Assessment of arterial supply to the stomach after bariatric surgery using multidetector CT arteriography.

PURPOSE: To describe residual arterial supply to the stomach after bariatric surgery via a systematic arterial-phase CT assessment approach that can aid in diagnosis and treatment of postoperative complications and facilitate planning for future procedures. METHODS: Arterial-phase CT of 46 patients who underwent Roux-en-Y gastric bypass (RYGB) or sleeve gastrectomy (SG) at 3 academic institutions were retrospectively reviewed to assess patency of left gastric artery (LGA), right gastric artery (RGA), gastroepiploic artery (GEA), and left inferior phrenic artery (LIPA) and presence of gastric perforators. RESULTS: In 25 RYGB and 21 SG patients, mean diameters were LGA 2.2 ± 0.4 mm, RGA 1.6 ± 0.5 mm, and GEA 1.7 ± 0.4 mm. On RYGB scans, all LGAs, RGAs, and 24/25 (96%) of GEAs were identified. Excellent to good patency was seen in 20/25 (80%) LGAs, 21/25 (84%) RGAs, and 23/24 (96%) GEAs. On SG scans, all LGAs, 18/21 (86%) of RGAs, and 20/21 (95%) GEAs were identified. Excellent to good patency was seen in 17/21 (81%) LGAs, 15/18 (83%) RGAs, and 20/20 (100%) GEAs. In terms of gastric perforators, LGA supply was seen on 23/25 (92%) of RYGB and 17/17 (100%) of SG scans. RGA supply was seen on 13/21 (62%) RYGB and 9/18 (50%) SG scans. GEA supply was seen on 19/23 (83%) RYGB scans. No gastric supply via GEA was seen on SG scans. CONCLUSION: In this study, arterial supply to the stomach through the LGA was consistently identified in all RYGB and SG cases, indicating an uncomplicated surgical approach with regard to preserving the LGA. Dedicated CT angiography protocol or catheter-directed angiography is recommended for accurate and comprehensive assessment of the gastric blood supply, particularly before surgical re-intervention.

Lymphoepithelial cysts of the pancreas. Can preoperative imaging distinguish this benign lesion from malignant or pre-malignant cystic pancreatic lesions?

CONTEXT: Lymphoepithelial cysts of the pancreas are rare true benign cystic tumors of the pancreas of uncertain etiology. Cystic neoplasms of the pancreas present a significant diagnostic dilemma in differentiating benign from premalignant or malignant variants. Since the first description of lymphoepithelial cysts in 1985, 109 cases have been reported in the literature. We describe 6 cases of this rare tumor, the preoperative imaging results, and a review the literature. PATIENTS: Five males and one female ranging in age from 47 to 76 years underwent resection for lymphoepithelial cysts. Five patients presented with abdominal pain related to the lesion and in one patient the lesion was discovered incidentally. Four patients had elevated serum CA 19-9 levels. Pre-operative imaging with a CT scan and MRI of the abdomen typically revealed a well defined hypodense mass with Hounsfield units (HU) in the range of 15 to 20. One patient had papillary projections into the lesion. The mean size was 3.3 cm (ranging from 1.8 cm to 4 cm). All lesions were exophytic off the pancreatic parenchyma (1 cyst was located in the head of the pancreas, 2 were in the body, and 3 were in the tail region). Pre-operative EUS-guided/CT-guided needle aspiration, when performed, was not diagnostic. All patients underwent resection (one pancreaticoduodenectomy, five left pancreatectomies) to remove these cystic neoplasms. Pathology revealed a cyst lined by non-dysplastic squamous cells surrounded by sheets of benign lymphocytes. No evidence of malignancy was found. CONCLUSION: Lymphoepithelial cysts of the pancreas are rare and are characteristically seen in men. While a hypodense mass (less than 20 HU) with papillary projections should be considered suspicious for lymphoepithelial cyst, a definitive diagnosis cannot be made solely based on preoperative imaging. EUS-guided biopsy coupled with biochemical/tumor marker studies are increasingly being used as a diagnostic tool to help differentiate between the various types of cystic pancreatic neoplasms. Imaging findings of lymphoepithelial cysts are non-specific and hence surgical resection is often required to rule out the presence of a malignant or pre-malignant cystic pancreatic lesion. In true lymphoepithelial cysts, malignant transformation is not seen and patients who have these cysts are not at increased risk of developing a pancreatic malignancy.

Endoscopy in the CT Scanner: a Multidisciplinary Approach to Difficult Cases.

Endoscopic interventions have been made safer with the use of fluoroscopy. This technique has limitations in patients with challenging anatomy. The combined use of endoscopy and CT fluoroscopy provides the added precision necessary to accomplish difficult interventions. In this video, we present two cases where endoscopy and CT fluoroscopy were used concurrently. While other publications have demonstrated the use of CT guidance to perform endoscopic interventions, this video also demonstrates the reverse-how endoscopic guidance can be used to make a CT-guided procedure possible. This video demonstrates the enhanced patient care possible when a multidisciplinary approach between interventional radiologists and surgeons is followed.

Prostate magnetic resonance imaging: The truth lies in the eye of the beholder.

PURPOSE: To determine the diagnostic accuracy and interobserver variability of radiologic interpretation of magnetic resonance imaging (MRI) performed for surgical planning before prostatectomy. PATIENTS AND METHODS: The records of 233 men undergoing prostatectomy with presurgical multiparametric 3T surface body coil MRI were reviewed. All initial films were read by a fellowship-trained body radiologist provided with relevant clinical information. A senior radiologist then reread all pelvic MRIs blinded to the initial interpretation with findings from both readings compared to final pathology. Kappa (κ) scores as well as sensitivity, specificity, positive predictive values (PPV), negative predictive value (NPV), and accuracy were determined. RESULTS: When considering extraprostatic extension (EPE), there was low concordance comparing the initial vs. repeat MRI interpretation (κ = 0.22). Additionally, when the senior radiologist reread his own initial interpretation (n = 93, blinded to initial result), concordance for EPE was greater (κ = 0.36) albeit similarly low. With regard to EPE, a comparison of initial MRI interpretation vs. reread by senior radiologist noted universal improvements in diagnostic characteristics including sensitivity (30.3% vs. 56.1%), specificity (80.2% vs. 88.6%), PPV (37.7% vs. 66.1%), NPV (74.4% vs. 83.6%), and accuracy (66.1% vs. 79.4%). In contrast, seminal vesicle invasion interpretation was more uniform whereby initial MRI interpretation vs. reread yielded similar sensitivity (18.2% vs. 27.3%), specificity (97.2% vs. 93.8%), PPV (40.0% vs. 31.6%), NPV (91.9% vs. 92.5%), and accuracy (89.7% vs. 87.6%). CONCLUSIONS: Even at a tertiary referral center, interobserver variability among radiologists regarding local extent of disease on prostate MRI is high. These observations underscore the importance of uniformity when defining criteria for EPE and seminal vesicle invasion to allow for optimal presurgical planning.

Synchronous Primary Renal Lymphoma and Renal Cell Carcinoma: Collision Tumors in the Same Kidney.

Background: Primary renal lymphoma (PRL) is an exceptionally rare disease with under 50 reported cases in the literature. PRL is an aggressive condition that can present with nonspecific symptoms and local invasion mimicking renal cell carcinoma (RCC). We present an unusual case involving a collision tumor between PRL and RCC. Case Presentation: The patient is a 62-year-old immunosuppressed man with an incidental left renal mass on cross-sectional imaging. Renal mass biopsy confirmed clear cell type RCC. He underwent robot-assisted, laparoscopic left radical nephrectomy for presumed RCC without evidence for extrarenal disease or discernable lymphadenopathy. Final pathology revealed a collision tumor, including PRL and RCC. Conclusion: To our knowledge, this is the first reported case within the literature describing a collision tumor between PRL and RCC. Although rare, it is important to consider PRL in the differential diagnosis of a solid renal mass, especially in patients with a prior history of transplantation and/or chronic immunosuppression.

Therapeutic approach guided by genetic alteration: use of MTOR inhibitor in renal medullary carcinoma with loss of PTEN expression.

Renal Medullary Cancer (RMC) is a rare and aggressive type of renal cell cancer that presents predominantly in patients with sickle cell hemoglobinopathies, and is typically metastatic at the time of presentation. Although platinum based chemotherapeutic regimens have recently emerged as the best option for producing a clinically significant response as reported in various case series, the response is far from satisfactory, as most RMC patients still succumb to their disease within a year of diagnosis. There is currently no standard of care for treatment of this disease. We report, to our knowledge, the first case of RMC where in molecular characterization of the tumor was used to guide therapy. In our patient, molecular analysis identified a decreased expression of Ribonucleotide Reductase M1(RRM1) and phosphatase and tensin homolog (PTEN). Based on these results of PTEN deficiency, we started our patient on everolimus (an MTOR inhibitor) maintenance after treating him with an induction chemotherapy regimen of Paclitaxel-Cisplatin-Gemcitabine (PCG). His tumor responded to induction therapy and he went into complete remission and remained in remission for 7 months. He is now alive about 14 months from his diagnosis and is asymptomatic with minimal disease. The rarity of RMC makes it very difficult to do any meaningful clinical trials in this group of patients. The overall prognosis for RMC remains very poor and knowledge about driver mutations may help in guiding therapy to improve survival in this select group of patients, where there is dearth of available therapies.

Circulating tumor cell levels are elevated in colorectal cancer patients with high tumor burden in the liver.

BACKGROUND: Metastatic spread is the most common cause of cancer-related death in colorectal cancer (CRC) patients, with the liver being the mostly affected organ. Circulating tumor cells (CTCs) are a prognostic marker in stage IV CRC. We hypothesized that tumor burden in the liver correlates with CTC quantity. METHODS: Blood (7.5 ml) was prospectively collected from 24 patients with novel stage IV CRC diagnosis. Baseline EpCAM+ CTCs were analyzed with the FDA-approved CellSearch® system. Clinicopathological data were collected, and hepatic tumor burden was determined by radiographic liver volumetry with contrast-enhanced CT scans. CRC primary tumors were immunohistochemically stained for EpCAM expression with BerEP4 monoclonal antibody. Statistical analyses were performed using 2-sample T-test, non-parametric Wilcoxon Rank-Sum test, and Fisher's exact test. RESULTS: CTCs were detected n 17 (71%) of 24 patients. The overall mean CTC number as determined by EpCAM-based CellSearch® detection was 6.3 (SEM 2.9). High baseline CTC numbers (≥3) correlated significantly with a high tumor/liver ratio (≥30%), and with high serum CEA levels, as determined by two-sample T-test on log-transformed data and by Fisher's Exact test on categorical data analysis (P < 0.05). The CRC primary tumors were consistently expressing EpCAM by immunostaining. CONCLUSIONS: High tumor burden in the liver and high baseline serum CEA levels are associated with high number of baseline CTCs in stage IV CRC patients. Future studies should further investigate the biological role and expression patterns of single CTCs in cancer patients to further improve personalized treatment strategies.

PET/CT in primary hepatic lymphoma with hepatic vein thrombus that extended into the inferior vena cava.

Primary hepatic lymphoma (PHL) is an extremely rare manifestation of extranodal non-Hodgkin's lymphoma (0.016% of all cases). Presented are CT, MRI, ultrasound, and (18)F fluoro-2-deoxy-D-glucose (FDG) PET/CT images, which characterized PHL and demonstrated hepatic vein thrombus that extended into the inferior vena cava--a feature not previously described. Recognition of this imaging pattern may help in the differential diagnosis of future such cases. FDG PET/CT was critical in confirming the diagnosis, staging, and demonstrating response to treatment.

Contradictory KRAS mutation test results in a patient with metastatic colon cancer: a clinical dilemma in the era of personalized medicine.

The KRAS oncogene is mutated in 40‒50% of colorectal cancers and confers resistance to EGFR-targeted therapy. In the clinic, agents such as cetuximab or panitumumab target the EGFR receptor for therapeutic benefit. Cetuximab was approved by the FDA in 2012 as first-line therapy for KRAS mutation-negative (wild-type), EGFR-expressing metastatic colorectal cancer, in combination with FOLFIRI (5-fluorouracil, irinotecan, leucovorin). Herein we report a case of metastatic colon cancer with conflicting testing results for the KRAS oncogene from two different reference laboratories. The discordant reports complicated the decision-making process regarding the administration of targeted anti-EGFR personalized therapy. As the second test result was wild-type from the same original pathological specimen, the patient was treated with cetuximab-containing combination chemotherapy and appeared to have a response after prior disease progression. It is unclear whether the observed response was fully due to regression of wild-type KRAS-containing tumor or any component of antibody-dependent cellular cytotoxicity to a heterogeneous tumor in this patient.

Circulating tumor cells are associated with diffuse spread in stage IV colorectal cancer patients.

BACKGROUND: Colorectal cancer (CRC) is the second leading cause of cancer-related deaths in the United States when combining both genders. Circulating tumor cells (CTCs) are a prognostic marker for stage IV CRC patients. We hypothesized that CTC quantity varies among stage IV CRC populations. METHODS: Blood (7.5 ml) was prospectively collected from 90 stage IV CRC patients. EpCAM(+) CTCs were analyzed with the FDA-approved CellSearch(®) system. CRC tumors were immunohistochemically stained for EpCAM expression. Imaging and clinicopathological data were collected. Statistical analysis was performed using correlation analysis, Kruskal-Wallis, Fisher exact, and log-rank test. RESULTS: CTCs were detectable in 36/90 (40%) patients. Diffuse CRC metastases were associated with the highest CTC prevalence (24/40 [60%]), in contrast to limited lung (2/19 [11%]) or liver (10/31 [32%]) metastases (P = 0.027). The overall mean CTC number was 2.0 (range 0-56.3). The mean CTC number in patients with diffuse metastases was significantly higher (3.7 [SEM ± 1.7, range 0-56.3]) than with limited lung metastases (0.1 [± 0.1; range 0-1]) or liver metastases (0.9 [± 0.3, range 0-7.0]) (P = 0.001). CRC tumors were consistently expressing EpCAM. CTC numbers did not correlate with serum CEA levels or other routine clinical parameters (P = N.S.). Patients with diffuse metastases had the poorest overall survival (P = 0.0042). CONCLUSIONS: CRC patients with diffuse metastases have the highest number of CTCs, in contrast to limited metastases to the liver or lungs. Future studies should correlate CTCs with recurrence patterns in patients with resected CRC lung or liver metastases to investigate whether CTCs represent micrometastatic disease causing early relapses.