OBJECTIVE: To evaluate the incidence and imaging findings of lymphoma after liver transplantation in children. MATERIALS AND METHODS: The authors reviewed records and imaging studies of children submitted to liver transplantation in the period between 2000 and 2008 in a single institution. RESULTS: Among 241 children submitted to liver transplantation, with a mean follow-up period of 41.4 ± 26.4 months, 16 (6.6%) had lymphoma. The mean age of the patients who developed lymphoma at the moment of transplantation was lower than in children who did not develop malignancy (23.9 ± 18.9 versus 38.0 ± 48.9 months; p = 0.02). The time interval between liver transplantation and the diagnosis of lymphoma ranged from 6 to 103 months. Clinical and radiological presentation was variable and the abdomen was the most common location of the tumor (n = 13; 81.3%), followed by chest and head and neck (n = 4; 25.0% each). Imaging findings included adenopathy, mediastinal, pulmonary and mesenteric masses, bowel wall thickening and hepatic and renal nodules. Four children (25.0%) died because of complications of lymphoma. CONCLUSION: Lymphomas are relatively uncommon and potentially fatal complications that may occur any time after pediatric liver transplantation, presenting different clinical and imaging findings.

Keywords: Lymphoma; Hepatic transplantation; Pediatrics; Imaging diagnosis; Postoperative complications.

OBJECTIVE: To describe the technique of computed tomography-guided percutaneous biopsy of pancreatic tumors with pneumodissection. MATERIALS AND METHODS: In the period from June 2011 to May 2012, seven computed tomography-guided percutaneous biopsies of pancreatic tumors utilizing pneumodissection were performed in the authors' institution. All the procedures were performed with an automatic biopsy gun and coaxial system with Tru-core needles. The biopsy specimens were histologically assessed. RESULTS: In all the cases the pancreatic mass could not be directly approached by computed tomography without passing through major organs and structures. The injection of air allowed the displacement of adjacent structures and creation of a safe coaxial needle pathway toward the lesion. Biopsy was successfully performed in all the cases, yielding appropriate specimens for pathological analysis. CONCLUSION: Pneumodissection is a safe, inexpensive and technically easy approach to perform percutaneous biopsy in selected cases where direct access to the pancreatic tumor is not feasible.

Keywords: Pancreatic neoplasms; Needle biopsy; Computed tomography.

OBJECTIVE: To establish an overview of computed tomography (CT)-guided percutaneous nephrostomy performed at a referral center for cancer, addressing the characteristics of patients submitted to this intervention, as well as the indications for it, the technical specificities of it, and its main complications. MATERIALS AND METHODS: This was a retrospective study involving a review of the electronic medical records and images of patients submitted to CT-guided percutaneous nephrostomy at a referral center for cancer between 2014 and 2016. RESULTS: A total of 201 procedures were evaluated. In most cases, the obstruction was caused by a malignant neoplasm. Complications occurred in 9.5% of the cases, and an additional intervention was required (typically for catheter repositioning) in 36.6%. Post-procedure complications were not found to be significantly associated with the type of previous cancer treatment, the technique used, the caliber of the drain used in the procedure, or the degree of dilatation of the collection system prior to the procedure. CONCLUSION: In cancer patients, CT-guided percutaneous nephrostomy is an effective treatment, with success rates and complication rates similar to those reported in the general population.

Keywords: Nephrostomy, percutaneous/methods; Nephrostomy, percutaneous/adverse effects; Computed tomography.

OBJECTIVE: To evaluate the accuracy of chest computed tomography (CT) in patients with suspected severe acute respiratory syndrome-related coronavirus-2 (SARS-CoV-2) infection at a cancer center. Materials and METHODS: This retrospective single-center study selected 91 patients who had chest CT and real-time polymerase chain reaction (RT-PCR) test collected at the same day. CT results were classified in negative, typical, indeterminate or atypical findings. Diagnostic accuracy, sensitivity and specificity were calculated for two different scenarios: in the first, only typical findings on CT were considered positive; in the second, both typical and indeterminate findings were considered positive. RESULTS: Mean patients’ age was 58.2 years, most were male (60.4%) and had prior diagnosis of cancer (85.7%). CT showed typical findings in 28.6%, indeterminate findings in 24.2% and atypical findings in 26.4%. RT-PCR results were positive for SARS-CoV-2 in 27.5%. The sensitivity, specificity and accuracy in the first and second scenarios were respectively 64.0%, 84.8% and 79.1%, and 92.0%, 62.1% and 70.3%. CONCLUSION: CT has a high accuracy for the diagnosis of SARS-CoV-2 infection. Different interpretation criteria can provide either high sensitivity or high specificity. CT should be integrated as a triage test in resource-constrained environments during the pandemic to assist in the optimization of PCR-tests, isolation beds and intensive care units.

Keywords: Computed tomography; Severe acute respiratory syndrome; Coronavirus infections; Cancer.

OBJECTIVE: To assess the technique, efficacy, and safety of computed tomography (CT)-guided percutaneous biopsies of head and neck masses. MATERIALS AND METHODS: This was a retrospective, single-center study of CT-guided percutaneous core-needle biopsies of head and neck masses.For the analysis of diagnostic accuracy, biopsy results were compared with the final diagnosis, which was determined by histological examination and clinical follow-up. RESULTS: We evaluated 74 biopsies performed in 68 patients.The mean age of the patients was 55.6 years.Most of the lesions (79.7%) were located in the suprahyoid region, and the maximum diameter ranged from 11 mm to 128 mm.The most common approaches were paramaxillary (in 32.4%), retromandibular (in 21.6%), and periorbital (in 14.9%).Five patients (6.8%) developed minor complications.The presence of a complication did not show a statistically significant association with any clinical, radiological, or procedure-related factor.Sufficient material for histological analysis was obtained in all procedures.Thirty-eight biopsies (51.4%) yielded a histological diagnosis of malignancy.There was a false-negative result in three cases (8.3%), and there were no false-positive results.The procedure had a sensitivity of 92.7%, a specificity of 100%, and an accuracy of 96.0%. CONCLUSION: Our results demonstrate that CT-guided percutaneous core-needle biopsy of head and neck lesions is a safe, effective procedure for obtaining biological material for histological analysis.

Keywords: Image-guided biopsy; Needle biopsy; Tomography, X-ray computed; Head and neck neoplasms.