Ayelet Ben-Barak

18F-FDG Avidity in Lymphoma Readdressed: A Study of 766 Patients

PET/CT with 18F-FDG is an important noninvasive diagnostic tool for management of patients with lymphoma, and its use may surpass current guideline recommendations. The aim of the present study is to enlarge the growing body of evidence concerning 18F-FDG avidity of lymphoma to provide a basis for future guidelines. Methods: The reports from 18F-FDG PET/CT studies performed in a single center for staging of 1,093 patients with newly diagnosed Hodgkin disease and non-Hodgkin lymphoma between 2001 and 2008 were reviewed for the presence of 18F-FDG avidity. Of these patients, 766 patients with a histopathologic diagnosis verified according to the World Health Organization classification were included in the final analysis. 18F-FDG avidity was defined as the presence of at least 1 focus of 18F-FDG uptake reported as a disease site. Nonavidity was defined as disease proven by clinical examination, conventional imaging modalities, and histopathology with no 18F-FDG uptake in any of the involved sites. Results: At least one 18F-FDG–avid lymphoma site was reported for 718 patient studies (94%). Forty-eight patients (6%) had lymphoma not avid for 18F-FDG. 18F-FDG avidity was found in all patients (100%) with Hodgkin disease (n = 233), Burkitt lymphoma (n = 18), mantle cell lymphoma (n = 14), nodal marginal zone lymphoma (n = 8), and lymphoblastic lymphoma (n = 6). An 18F-FDG avidity of 97% was found in patients with diffuse large B-cell lymphoma (216/222), 95% for follicular lymphoma (133/140), 85% for T-cell lymphoma (34/40), 83% for small lymphocytic lymphoma (24/29), and 55% for extranodal marginal zone lymphoma (29/53). Conclusion: The present study indicated that with the exception of extranodal marginal zone lymphoma and small lymphocytic lymphoma, most lymphoma subtypes have high 18F-FDG avidity. The cumulating evidence consistently showing high 18F-FDG avidity in the potentially curable Burkitt, natural killer/T-cell, and anaplastic large T-cell lymphoma subtypes justifies further investigations of the utility of 18F-FDG PET in these diseases at presentation.

The incremental value of 18F-FDG PET/CT in paediatric malignancies

Purpose18F-fluorodeoxyglucose (18F-FDG) positron emission tomography (PET) imaging has been used in the assessment of paediatric malignancies. PET/CT increases the diagnostic accuracy in adult cancer patients. The present study assesses the incremental value of FDG PET/CT in paediatric malignancies.MethodsA total of 118 18FDG PET/CT studies of 46 paediatric patients were reviewed retrospectively. PET and PET/CT results were classified as malignant, equivocal or benign, compared on a site- and study-based analysis, and also compared with the clinical outcome.ResultsThree hundred and twenty-four sites of increased FDG uptake were detected. Discordant PET and PET/CT interpretations were found in 97 sites (30%) in 27 studies (22%). PET yielded a statistically significant higher proportion of equivocal and a lower proportion of benign lesion and study results (p < 0.001) than PET/CT. With PET there were 153 benign (47%), 84 (26%) equivocal and 87 (27%) malignant sites, while PET/CT detected 226 benign (70%), 10 (3%) equivocal and 88 (27%) malignant lesions. PET/CT mainly improved the characterisation of uptake in brown fat (39%), bowel (17%), muscle (8%) and thymus (7%). The study-based analysis showed that 17 equivocal and seven positive PET studies (20%) were interpreted as benign on PET/CT, while three equivocal studies were interpreted as malignant. The study-based sensitivity and specificity of PET/CT were 92% and 78% respectively.ConclusionPET/CT significantly improved the characterisation of abnormal 18FDG foci in children with cancer, mainly by excluding the presence of active malignancy in sites of increased tracer activity.

An outbreak of Mycobacterium mucogenicum bacteremia in pediatric hematology-oncology patients.

Background and Aims: Mycobacterium mucogenicum (MM) is a rapidly growing nontuberculous mycobacterium that is commonly identified in tap water that can rarely cause bacteremia. We describe an outbreak of MM bacteremia among pediatric hematology-oncology patients. Methods: Charts of children with MM bacteremia were retrospectively reviewed. Demographic data, underlying conditions, central venous catheter (CVC) type, duration of bacteremia, and treatment were retrieved. Epidemiologic investigation was conducted during the outbreak including environmental sampling. Results: During an 8-month period (September 2005–May 2006), 8 patients aged 1.5 to 17 years had MM bacteremia. Seven patients had underlying malignancy and 1 with thalassemia major had bone marrow transplantation. The mean number of positive blood cultures was 4.2 (1–11) per patient. Two patients received antibiotic treatment in addition to removal of CVC. All patients were cured. Almost 60 environmental samples were obtained from surfaces, ice, and municipal water supply. All were negative and no source was documented. Infection control measures included emphasis on guidelines for prevention of CVC-associated infections. No cases occurred before and after this outbreak. Conclusions: MM is a rare agent of CVC-associated bacteremia. Removal of the CVC may be sufficient for management of bacteremia. In the absence of definite source identification, reinforcement of standard infection control measures can be successful in containing outbreaks.

Treatment with oral ribavirin and IVIG of severe human metapneumovirus pneumonia (HMPV) in immune compromised child

To the Editor: Pneumonia in an immunocompromised host poses a diagnostic and treatment challenge, especially in light of emerging pathogens. Human metapneumovirus (HMPV) has recently emerged as a new pathogen associated with bronchiolitis in infants, which can cause severe pneumonia and respiratory failure among compromised hosts. An 8-year-old malewith abdominal Burkitt lymphoma and bone marrow involvement diagnosed 2months previously, presentedwith fever, general fatigue, mild cough, and oral ulcers. On admission he had a temperature of 39.48C, and no obvious source of infection. His total leukocyte count was 100 cells/ml and he was treated with piperacillin/tazobactam and amikacin. By day 4, he had a nasal discharge and worsened cough, with rales, severe dyspnea, and oxygen desaturation (88% on ambient air). A nasal wash was taken for respiratory pathogens (respiratory syncytial virus, adenovirus, influenza A and B, parainfluenza 1, 2, 3, H1N1, HMPV), in addition to sputum culture and urine for legionella antigen. Chest X-ray (Fig. 1A) and computerized tomography, demonstrated bilateral infiltrates. He developed low blood pressure and severe respiratory distress, such that bronchoalveolar lavage (BAL) could not be done. Antibiotic treatment was changed to meropenem, vancomycin, levofloxacin, and caspofungin. Cultures and urinary legionella antigen were negative. Respiratory secretions were positive for HMPV (IFA). Because of severe immunosuppression and his poor clinical condition, the patient was given oral ribavirin and a single dose of IVIG. Four days later he was afebrile with no respiratory effort, and his WBC rose to 12,000 cells/ml while on G-CSF. Repeat test for HMPVwas negative after 8 days and hewas discharged. The patient was treated for three more days with ribavirin (total of 12 days) and 7 days with levofloxacin, and had a complete remission (Fig. 1B). Polymicrobial pneumonia could not be excluded, sinceBALwas not done although sputum was negative for other pathogens. Therefore, he was treated with antibacterial agents as well. HMPVisaparamyxovirus,firstdescribed in2001inchildrenwith respiratory disease [1].Most healthy children are seropositive by the age of 5 years, with reinfections throughout life [2]. Normal hosts may have upper and lower respiratory tract infections. An immunocompromised host can develop severe pneumonia, respiratory failure, shock, and death [3]. England et al. [3] described 163 immunocompromised patients who underwent BAL for atypical pneumonia, five of whom were positive for HMPV; four of these five died within 40 days due to severe pneumonia. There are no specific recommendations regarding treatment of HMPV. The virus is susceptible to ribavirin in vitro and in animal models [4]. Until now there have been few reports in the literature describing cases treated successfully with a combination of intravenousribavirinandimmunoglobulin[5],andnorandomizedcontrol trials are available. The evidence of severe outcome in these patients and scattered reports of successful treatment suggest the need for other studies. Ribavirin and IVIG may be a suitable treatment for severe cases.

Mitral valve destruction by Hodgkin's lymphoma-associated Loefler endocarditis.

We present a case of nearly total posterior mitral leaflet destruction due to Loeffler endocarditis associated with Hodgkin’s lymphoma in a 15-year-old adolescent. The patient was treated medically with subsequent surgical mitral valve replacement. Cardiac aspects of hypereosinophilic syndrome are also discussed.

Ultrasound-guided core biopsy as the primary tool for tissue diagnosis in pediatric oncology.

Introduction: Traditionally in pediatric oncology, biopsies were incisional, with a recent alternative of percutaneous imaging-guided biopsies. In our department, ultrasound (US)-guided core biopsy is the first choice for tissue diagnosis in the pediatric population. We retrospectively reviewed our experience and assessed the accuracy rate, safety, and availability of the procedure. Materials and Methods: Pediatric US-guided biopsies performed in our hospital between November 2003 and November 2011 were studied. Data collection included demographics, clinical and procedural data, and follow-up. Results: A total of 213 biopsies were performed on 191 patients: 40 known oncologic patients and 173 to establish diagnosis. Seventeen biopsies were excluded, as malignancy was not suspected. Sixty-five percent of the patients had a biopsy within a day. A total of 138 biopsies with tumor at the biopsy site were correctly diagnosed and 4 were missed. Fifty-eight patients were negative for tumor. The sensitivity of our ultrasound-guided core biopsy is 97.1%, specificity 100%, and accuracy 97.9%. We found no complication related to sedation, and 2 procedural complications—bleeding from the biopsy site and seeding of tumor cells—were reported. Discussion: We find US-guided core biopsy for suspected malignancy in the pediatric population to be highly available, safe, and very accurate, having a potential to become the procedure of choice.

Mycobacterium phocaicum bacteremia: an emerging infection in pediatric hematology-oncology patients.

Nontuberculous mycobacteria may cause central venous catheter-associated bacteremia. Between March 2011 and October 2013, 6 cases of Mycobacterium phocaicum bacteremia were found in the pediatric hematology-oncology department. All patients recovered. No positive blood culture was documented after removal of the central venous catheter. All 4 patients with pulsed field gel electrophoresis had the same pattern, different from the water sample, suggesting a common water source.

Syncytial variant of nodular sclerosing Hodgkin lymphoma in children: A prognostic factor?

ABSTRACT Nodular sclerosing Hodgkin lymphoma (HL) has an excellent prognosis in children. The syncytial variant (SV) of HL in adults represents a clinic pathologic entity with a worse outcome. We report the clinical features and the course of the disease of three children with refractory HL. The three patients with SV were analyzed in a retrospective multi-institutional study conducted in Israel in 51 children diagnosed with refractory or recurrent HL between 1997 and 2014. All the three children developed multiple recurrences soon after diagnosis. All three received at least three different chemotherapy combinations with autologous bone marrow transplantation for two patients, allogenic bone marrow transplantation in one, and immunotherapy in one. One patient died of disease, one is in complete response of the disease but developed a second metastatic malignancy, and one is alive without disease. This retrospective study shows that SV histology may be a prognostic factor for poor outcome in children diagnosed with HL.