Effect of Hepatic Perfusion on Microwave Ablation Zones in an Ex Vivo Porcine Liver Model.

PURPOSE: To compare the size of ablation zones derived from nonperfused ex vivo livers with ablation zones created using an ex vivo perfused porcine liver model. MATERIALS AND METHODS: Six fresh porcine livers were used to evaluate microwave ablation (MWA). Perfused (n = 3) and nonperfused (n = 3) livers were warmed to 37°C by oxygenated, O-positive human blood reconstituted with Ringer solution, using an organ perfusion circuit. During MWA, perfusion was discontinued in the nonperfused group and maintained in the perfused group. After MWA (140 watts × 2 min at 2.45 GHz) with the Acculis MTA System (AngioDynamics, Latham, New York), ablation zones were bisected sagittally. Sections were stained with nicotinamide adenine dinucleotide (NADH) and hematoxylin-eosin to assess viability of cells in ablation and marginal zones. RESULTS: Comparison of 22 MWA zones (9 in perfused group, 13 in nonperfused group) was performed. Ablation zones demonstrated a central "white" and peripheral "red" zone. Cells in the white zone were nonviable with no NADH staining. The red zone showed progressive NADH staining toward the periphery, suggesting incomplete cell death. White and red zones of the perfused group were significantly smaller compared with the nonperfused group (short axis, 17.8 mm ± 2.7 vs 21.1 mm ± 3.2, P = .003; long axis, 40.69 mm ± 3.9 vs 39.63 mm ± 5.2, P = .44; intermediate zone,1.33 mm ± 0.04 vs 2.7 mm ± 0.14, P < .0001; mean ± SD). CONCLUSIONS: MWA algorithms provided by this manufacturer are based on nonperfused organ data, which overestimate ablation zone size. Data from perfused liver models may be required for more accurate dosimetry guidelines.

Biological and Prognostic Significance of the Morphological Types and Vascular Patterns in Colorectal Liver Metastases (CRLM): Looking Beyond the Tumor Margin.

Patients with encapsulated colorectal liver metastases (CRLM) have a better prognosis than those without a capsule. The reason for the encapsulation is unknown. Hypoxia inducible factor-1α (HIF-1α) increases tumor angiogenesis and tumor tissue expression is associated with reduced survival. Our aim was to determine whether the good prognosis of encapsulated CRLM is associated with reduced HIF-1α expression by the cancer.The study selected only patients who had not undergone neoadjuvant chemotherapy prior to a potentially curative hepatectomy for CRLM. From 30 selected patients, serial sections were cut from a single randomly selected metastasis. Morphology was assessed following H&E staining. Tumor hypoxia, vascular endothelial growth factor (VEGF), proliferation, and microvascular density (MVD) were assessed by immunostaining for HIF-1α and carbonic anhydrase-9 (CA-9), VEGF, Ki67, and cluster of differentiation-31, respectively. MVD was calculated in the vascular hot spots. Pathology was reported without clinical outcome information. Actual long-term survival was recorded.Thirteen (43%) of the cancers were encapsulated CRLM containing glands which were large, complex, and cribriform. Thirteen (43%) were infiltrative CRLM and their glands were small, closely packed, and rounded with vessels in the interglandular fibrous tissue with no capsule; 3 (10%) had a mixed picture. Encapsulated CRLM had a higher expression of HIF-1α (58% vs 8%, P = 0.03), CA-9 (42% vs 0%, P = 0.04), and VEGF (92% vs 25%, P = 0.02). MVD was lower in the encapsulated CRLM group (37 mm vs 143 mm, P < 0.001). The median follow-up was 115 months. The encapsulated CRLM group had a better overall and 5-year survival (relative hazard: 0.58, P = 0.057 and hazard ratio: 0.52, P = 0.044).There are 2 main morphological appearances of CRLM which have very different long-term survival following liver resection surgery. The morphology is associated with differences in expression of HIF-1α, CA-9, VEGF, and angiogenesis.

Episodic biliary obstruction due to an intrahepatic biliary cystadenoma: a case report.

INTRODUCTION: Biliary cystadenoma is a rare, benign neoplasm of the bile ducts with malignant potential. Symptoms, predominantly right hypochondrial pain and the feeling of a lump or fullness are usually due to the mass effect. Jaundice is rare. This is the fifth reported patient with an intrahepatic biliary cystadenoma giving rise to episodic biliary obstruction, which is usually caused by choledocholithiasis or periampullary carcinoma. Considering the mean age of previous similar patients (53.5, standard deviation 14.6 years), the early age of presentation is very unusual in our patient. CASE PRESENTATION: A 25-year-old Asian woman presented with right hypochondrial pain and episodic biliary obstruction. Contrast enhanced computed tomography revealed a cystic mass in segment 4B and protruding into and along the left hepatic duct. Laparotomy confirmed the contrast enhanced computed tomography findings and histology revealed an intrahepatic mucinous biliary cystadenoma. CONCLUSION: Biliary cystadenoma should be considered as a differential diagnosis in patients with cystic liver lesions who present with episodic biliary obstruction. Due to the reported malignant potential, radical surgery such as wide local excision of the lesion or hepatic resection is needed to minimize the risk of local recurrence.

Colonoscopic ultrasound is associated with a learning phenomenon despite previous rigid probe experience.

Colonoscopic ultrasound (CUS) enables total colonoscopic examination combined with staging of tumor. Rigid probe transrectal ultrasound (TRUS) is reliable in assessing rectal cancer. Both the modalities are associated with an initial learning curve. We evaluated the predictability CUS in preoperative staging of rectal cancer during the learning curve, despite experience with TRUS. Forty-four patients with non-obstructing rectal cancer were assessed by colonoscopy and colonic ultrasound using a 7.5 MHz rotating transducer. Accuracy of ultrasound staging was compared with pathological staging. Tumor staging and nodal staging at pathology and ultrasound were named pT, pN and uT, uN, respectively. The pathological staging was pT1 in two (4.5%), pT2 in 16 (36%), pT3 in 21 (48%) and pT4 in five (11.5%) rectal cancer specimens. CUS understaged the tumor in 11 cases and overstaged it in 10 cases. Overall, the positive predictive value was 61%, negative predictive value 73%, sensitivity 61%, and specificity 73%. Lymph nodes were not visualized in 14. The overall un-weighted kappa of CUS staging of RC was 0.18 (poor). The predictive value in tumor staging of CUS is suboptimal in the learning phase, despite previous experience with TRUS.