Nasopalpebral Schwannomas and Human Immunodeficiency Virus Infection.

OBJECTIVE: To report a case of a schwannoma of nasopalpebral location, occurring in a human immunodeficiency virus (HIV)-positive patient. CLINICAL PRESENTATION AND INTERVENTION: A 55-year-old man presented with a nasopalpebral painless tumefaction, pneumopathy and HIV-related immunodepression after stopping combination antiretroviral therapy. Magnetic resonance imaging showed subcutaneous masses, with contrast enhancement of the left nose pyramid, internal cantus and inferior palpebral area, suspicious of Kaposi sarcoma. The resected specimen showed schwannoma histology, with tumor cells expressing S100 protein and WT1. CONCLUSION: The features of a rare case of facial schwannoma of nasopalpebral location in an HIV-positive patient are reported. The diagnosis may be difficult before microscopic examination, with imaging features suggesting a Kaposi sarcoma.

Susceptibility-weighted imaging to visualize blood products and improve tumor contrast in the study of brain masses.

PURPOSE: To evaluate the diagnostic value of susceptibility-weighted imaging (SWI) for studying brain masses. MATERIALS AND METHODS: SWI is a high-resolution, three-dimensional, fully velocity-compensated gradient-echo sequence that uses both magnitude and phase data. Custom postprocessing is applied to enhance the contrast in the magnitude images between tissues with different susceptibilities. This sequence was applied to 44 patients (24 males and 20 females, 15-89 years old, mean age = 50.3 years) with brain masses, pre- and/or postcontrast, and compared with conventional sequences (T1, T1 postcontrast, T2, proton density (PD), fluid-attenuated inversion recovery (FLAIR) and diffusion-weighted imaging (DWI) at 1.5T). Correlation with pathology was obtained in 12 cases. All images were reviewed independently by three radiologists. RESULTS: In the evaluation of tumor visibility, boundary definition, blood products, venous vasculature, architecture, and edema, SWI gave better information than the standard T1-weighted postcontrast images in 11%, 14%, 71%, 73%, 63%, and 75% of the data, respectively, in a subgroup of 38 patients. This demonstrates that the information presented by SWI is complementary in nature to that available from conventional methods. On the whole, SWI was much more sensitive for showing blood products and venous vasculature. SWI showed a useful FLAIR-like contrast and complemented the information obtained by conventional T1 postcontrast sequences regarding the internal architecture of the lesions. Good pathologic correlations were found for blood products as predicted by SWI. CONCLUSION: SWI should prove useful for tumor characterization because of its ability to better highlight blood products and venous vasculature and reveal new internal architecture.

Radiofrequency ablation for the treatment of liver tumors in the caudate lobe.

PURPOSE: To evaluate the effectiveness of radiofrequency (RF) ablation for liver tumors located in the caudate lobe. MATERIALS AND METHODS: Ten patients (46-79 years of age; median, 70 y), eight with hepatocellular carcinoma (HCC) and cirrhosis and two with colorectal metastases in the caudate lobe, were treated with 5.8% NaCl tissue-perfused monopolar (n=7) or bipolar (n=3) RF ablation. The median tumor diameter was 41 mm (range, 25-70 mm). Procedures were performed under ultrasound and computed tomography (CT) guidance in eight and two patients, respectively. One month later, the treatment response was assessed by CT. RESULTS: Transhepatic right intercostal and transomental anterior epigastric routes were used for tumor puncture in eight and two patients, respectively. The entire RF ablation treatment required one or two procedures (median, 1.5), including two to 15 electrode repositionings (median, 6). After RF ablation procedure, one patient experienced jaundice that resolved spontaneously. In one patient, CT follow-up showed asymptomatic segmental biliary duct dilations. Median total hospital stay was 3 days (range, 2-9 d). Complete ablation was achieved in nine of 10 tumors. In one patient, ethanol ablation was necessary to complete RF ablation treatment. After a median follow up of 9.5 months (range, 5-25 mo), three patients remained tumor-free and seven had tumor relapse: two local, four distant, and one mixed. Repeat RF ablation was successfully performed in four cases. CONCLUSION: RF ablation of liver tumors located in the caudate lobe is effective despite the deep location of tumors and the vicinity of major vessels.

Large infiltrative hepatocellular carcinomas: treatment with percutaneous intraarterial ethanol injection alone or in combination with conventional percutaneous ethanol injection.

PURPOSE: To retrospectively evaluate patients' tolerance and the effectiveness of percutaneous intraarterial ethanol injection (PIAEI), alone or combined with conventional percutaneous ethanol injection (PEI), for treatment of advanced hepatocellular carcinoma (HCC). MATERIALS AND METHODS: Neither institutional review board approval nor informed consent was required for this retrospective study; however, all patients had given their consent to be treated with PIAEI. Fourteen men and four women with cirrhosis and HCC who were ineligible for conventional curative treatment (largest tumor diameter, 35-90 mm; mean, 52 mm +/- 16 [standard deviation]) and whose supplying arteries were visible on computed tomographic (CT) and color Doppler ultrasonographic (US) images were treated with US-guided PIAEI-either alone or combined with PEI. Twelve patients had infiltrative tumors, and six had nodular tumors. Four patients had portal venous tumor involvement. Tumor necrosis and recurrence were evaluated with CT, and 1- and 2-year survival rates were evaluated with Kaplan-Meier analysis. RESULTS: In four patients, the main tumor was treated with PIAEI only, and in 14 patients, the main tumor was treated with combined PIAEI and PEI. One patient died of myocardial infarction before CT evaluation. Tumor necrosis was complete in 15 (88%) and incomplete in two (12%) of 17 patients. Results of subsequent surgery performed in three patients confirmed the radiologic findings: complete tumor necrosis in two patients and incomplete necrosis in one patient. Two severe PIAEI-related complications occurred: liver abscess, which resolved, and fatal acute pancreatitis. During the follow-up period (mean, 15 months +/- 6.7), six patients died owing to recurrent HCC, and 10 patients were alive with no detectable tumor after a mean follow-up period of 18 months +/- 11. One- and 2-year survival rates were 76.6% and 44.5%, respectively. CONCLUSION: For patients with advanced HCC who are ineligible for other curative options, PIAEI could be an effective treatment, despite the associated risk of severe complications.

Clinical applications of neuroimaging with susceptibility-weighted imaging.

Susceptibility-weighted imaging (SWI) consists of using both magnitude and phase images from a high-resolution, three-dimensional, fully velocity compensated gradient-echo sequence. Postprocessing is applied to the magnitude image by means of a phase mask to increase the conspicuity of the veins and other sources of susceptibility effects. This article gives a background of the SWI technique and describes its role in clinical neuroimaging. SWI is currently being tested in a number of centers worldwide as an emerging technique to improve the diagnosis of neurological trauma, brain neoplasms, and neurovascular diseases because of its ability to reveal vascular abnormalities and microbleeds.