Pediatric Lymphedema: Study of 180 Patients Referred to a Tertiary Lymphedema Clinic.

BACKGROUND: Lymphedema is due to dysfunction of the lymphatic system. It can be primary or secondary. Pediatric lymphedema is more often primary and is a chronic disease with a heavy burden on quality of life. METHODS: Medical records of patients under 18 years of age referred between 1996 and 2021 to the specialized lymphedema clinic at the Sainte-Justine University Hospital Center were reviewed. Demographic data, sex, age at presentation, location of the lymphedema, clinical features, genetic testing, symptoms, complications, investigations, and treatment were collected. RESULTS: Of 180 referred patients, lymphedema was confirmed in 151, and 137 were primary lymphedema. Median age of apparition of primary lymphedema was 7.00 years and was significantly lower in boys than in girls. Primary congenital lymphedema was more frequent in boys (51.0%, 27.3% in girls, P = .007), and onset of primary lymphedema during adolescence was more frequent in girls (53.4%, 25.0% in boys, P = .001). Lower limbs were the most impacted (88.3%). Sixty patients had genetic testing, and 38 (63.3%) of them were discovered to have a pertinent genetic mutation. The most common mutated gene was the FLT4 gene (in 9 patients). Seven patients (5.1%) had associated extensive/central lymphatic malformation and 24 (17.6%) had a polymalformative syndrome/syndromic lymphedema. CONCLUSIONS: Pediatric lymphedema is more frequent in girls, usually involves lower limb, and is most often sporadic, but often associated with a genetic mutation, and genetic testing should be performed.

Evaluation of physiological Waldeyer's ring, mediastinal blood pool, thymic, bone marrow, splenic and hepatic activity with 18F-FDG PET/CT: exploration of normal range among pediatric patients.

INTRODUCTION: While 18F-FDG PET/CT pediatrics applications have increased in number and indications, few studies have addressed normal maximum standardized uptake values (SUVmax) of referral organs in children. The purpose of this study is to assess these in a cohort of pediatric patients. MATERIAL AND METHODS: 285 18F-FDG PET/CT scans in 229 patients were reviewed. SUVmax were assessed for mediastinal blood pool (MBP), thymus (T), liver (L), spleen (S), bone marrow (BM) and Waldeyer's Ring (Wald). L/MBP and S/L ratios were calculated. Same day complete blood counts (CBC) were available for 132 studies and compared to BM and S. Means, standard deviations and correlation coefficients with age, weight and body surface area (BSA) were calculated. RESULTS: Weak correlation with age, weight or BSA was found for Wald. Strong correlations with weight/BSA more than with age were demonstrated for MBP, L and BM and moderate for S and T. After initial decrease between age 0 and 2, thymic activity peaked at age 11 years then involuted. No correlation was found between CBC ad BM or S. In 28 studies, L was less or equal to MBP. In 74 S was superior to L. CONCLUSIONS: Referral organs 18F-FDG uptake varies in children more in relation with weight and BSA than with age for key referral organs, such as L, S and MBP. In a significant number of studies, L activity may impede evaluation of treatment response in comparison with MBP or inflammation/infection evaluation in comparison with S.

New interinstitutional, multimodal presurgical evaluation protocol associated with improved seizure freedom for poorly defined cases of focal epilepsy in children.

OBJECTIVE: In an attempt to improve postsurgical seizure outcomes for poorly defined cases (PDCs) of pediatric focal epilepsy (i.e., those that are not visible or well defined on 3T MRI), the authors modified their presurgical evaluation strategy. Instead of relying on concordance between video-electroencephalography and 3T MRI and using functional imaging and intracranial recording in select cases, the authors systematically used a multimodal, 3-tiered investigation protocol that also involved new collaborations between their hospital, the Montreal Children's Hospital, and the Montreal Neurological Institute. In this study, the authors examined how their new strategy has impacted postsurgical outcomes. They hypothesized that it would improve postsurgical seizure outcomes, with the added benefit of identifying a subset of tests contributing the most. METHODS: Chart review was performed for children with PDCs who underwent resection following the new strategy (i.e., new protocol [NP]), and for the same number who underwent treatment previously (i.e., preprotocol [PP]); ≥ 1-year follow-up was required for inclusion. Well-defined, multifocal, and diffuse hemispheric cases were excluded. Preoperative demographics and clinical characteristics, resection volumes, and pathology, as well as seizure outcomes (Engel class Ia vs > Ia) at 1 year postsurgery and last follow-up were reviewed. RESULTS: Twenty-two consecutive NP patients were compared with 22 PP patients. There was no difference between the two groups for resection volumes, pathology, or preoperative characteristics, except that the NP group underwent more presurgical evaluation tests (p < 0.001). At 1 year postsurgery, 20 of 22 NP patients and 10 of 22 PP patients were seizure free (OR 11.81, 95% CI 2.00-69.68; p = 0.006). Magnetoencephalography and PET/MRI were associated with improved postsurgical seizure outcomes, but both were highly correlated with the protocol group (i.e., independent test effects could not be demonstrated). CONCLUSIONS: A new presurgical evaluation strategy for children with PDCs of focal epilepsy led to improved postsurgical seizure freedom. No individual presurgical evaluation test was independently associated with improved outcome, suggesting that it may be the combined systematic protocol and new interinstitutional collaborations that makes the difference rather than any individual test.

Case Report 18F-FDG PET/CT of Pseudomyogenic Hemangioendothelioma.

Hemangioendotheliomas are a heterogeneous group of vascular neoplasm that may affect the liver, bone, and soft tissues. Among its variants, pseudomyogenic hemangioendothelioma is rarely encountered. Pseudomyogenic hemangioendothelioma is usually characterized by multiple soft tissue lesions, with occasional bone lesions. Fewer than 20 cases with exclusive involvement of bone structures have been reported. We describe a case of pseudomyogenic hemangioendothelioma involving multiple bony structures but without soft tissue involvement in a 7-year-old girl, imaged with F-FDG PET/CT at diagnosis and during treatment with mammalian target of rapamycin inhibitors.

Gray Zone Lymphoma Arising in the Neck of a Teenager With a Germline Mutation in TP53.

Gray zone lymphoma is an aggressive disease for which appropriate management is still debated. We report a 15-year-old girl with a cervical mass, an enlarged ipsilateral tonsil, and anemia. Both sites showed hypermetabolism on F18-FG positron emission tomography/CT. Surgical resection was diagnostic of Epstein-Barr virus-negative gray zone lymphoma cervical and tonsillar involvement. No abnormality was found in cytogenetic analysis on tumor cells. However, exome sequencing in peripheral blood DNA revealed a germline mutation in TP53. Complete response was achieved after surgery and 6 cycles of rituximab with dose-adjusted etoposide, prednisone, vincristine, cyclophosphamide, and doxorubicin regimen.

Solid Pseudo-Papillary Tumor Mimicking as Complicated Pseudocyst: Multimodality Imaging and Pathological Correlation.

Pancreatic neoplasm is very rare in the pediatric population. Malignant tumors represent less than 0.2% of pediatric cancer-related mortality. Pancreas lesions can be from exocrine or endocrine origin or present themselves as cystic masses. Clinical, biological, and radiological findings usually are sufficient to establish diagnosis, but in some cases, they may be misleading. We present the case of a young patient presenting a pancreatic mass where anatomical and metabolic characteristics of the lesion were discordant to the final diagnosis.

Lymphoscintigraphy of Chylous Anomalies: Chylothorax, Chyloperitoneum, Chyluria, and Lymphangiomatosis-15-Year Experience in a Pediatric Setting and Review of the Literature.

In the pediatric setting, lymphoscintigraphy is used mostly for the evaluation of lymphedema. Only a few cases of chylous anomalies and lymphatic malformations imaged with lymphoscintigraphy have been reported in the literature. The aim of this study was to review the use of lymphoscintigraphy in those pathologies. Methods: All lymphoscintigraphy studies performed for chylous anomalies between 2001 and 2017 in our hospital were retrospectively reviewed. The results were correlated to clinical and radiologic findings. Lymphoscintigraphy consisted of sequential imaging after injection of 3.7-9.25 MBq (100-250 µCi) of 99mTc-filtered sulfur colloid at the level of the feet or hands. Results: Twenty-five studies were performed on 21 patients. Fourteen studies were obtained for the evaluation of chylothorax. Eleven were performed for chyloperitoneum, chyluria, chylopericardium, exudative enteropathy, or lymphangiomatosis. Ten studies were positive for lymphatic leakage, and 1 had uncertain results. After correlation with radiologic findings and follow-up, there were 7 true-negative and 5 false-negative results (previous 67Ga-interfering activity in 1, injection in only the hands in 3, and a low-fat diet in 1). One study became positive after injection in the feet, and another became positive after a switch to a high-fat diet. Conclusion: Lymphoscintigraphy is a useful tool for imaging lymphatic anomalies in children. Suggestions to optimize results include placing the patient on a high-fat diet, withholding octreotide, injecting the 4 extremities, and imaging with SPECT/CT.

False Negative 18F-fluorodeoxyglucose Positron Emission Tomography/Computed Tomography in Primary B-cell Lymphoma of the Bone.

We present a case of a 15-year-old male with primary bone lymphoma who was initially referred for suspicion of chronic osteomyelitis of the mandible. A bone scan and gallium scan demonstrated congruent uptake in the mandible, suggestive of chronic osteomyelitis. A biopsy subsequently showed B-cell lymphoma of the bone with low Ki-67. A fluorodeoxyglucose positron emission tomography (FDG-PET) scan performed before therapy for staging revealed no increased uptake in the mandible. This case shows an atypical presentation of a rare disorder and is presented to emphasize the importance of baseline FDG-PET.

18F-FDG-PET/CT Imaging of Thoracic and Extrathoracic Tuberculosis in Children.

Tuberculosis (TB) remains a major health problem, affecting approximately one-third of the world׳s population. The tubercle bacillus can affect virtually any organ of the human body and if left untreated can lead to severe morbidity and death. Diagnosis of active TB is challenging, especially in children. As a "great imitator," the disease can mimic numerous other pathologies, both clinically and at imaging. Although recognition of active TB is crucial to initiate adequate treatment in a timely fashion, thereby preventing transmission of disease, differentiation of active and quiescent disease is not always straightforward. Since the first reports more than 20 years ago, FDG-PET/CT imaging has been shown to detect active disease with accuracy equal or superior to other conventional imaging modalities. The role of FDG-PET in evaluating patients with TB is rapidly expanding. FDG-PET/CT can effectively identify foci of intrathoracic and extrathoracic TB, assess disease activity, differentiate between active and latent disease, monitor response to therapy, identify potential biopsy targets, and serve as a surrogate end point for new drug trials. Efficacy of FDG-PET/CT in the especially challenging pediatric population will be the focus of this review.

Timing of Hormone Withdrawal in Children Undergoing 131I Whole-Body Scans for Thyroid Cancer.

BACKGROUND: Little objective pediatric data exist to guide the optimal time needed to achieve thyroid-stimulating hormone (TSH) levels ≥30 µIU/mL prior to performing 131I or 123I whole-body scan (WBS) imaging in children with thyroid cancer in the post-thyroidectomy period or after hormone discontinuation. METHODS: Retrospective study of patients aged 5-19 years who underwent WBS. Patient data collection included type and duration of withdrawal (liothyronine [L-T3], levothyroxine [L-T4], or post-thyroidectomy status without hormonal replacement) and TSH measured prior to WBS (level and timing). RESULTS: A total of 175 TSH level measurements were performed in 68 patients. Thirty-five TSH values were obtained 2-7 weeks postoperatively and 101 values were obtained 2-8 weeks post L-T4 withdrawal. One patient in each group had a TSH level <30 µIU/mL. There was no difference in TSH levels between 3 weeks and 4 weeks postoperatively (p = 0.14) or post L-T4 cessation (p = 0.21). Thirty-nine TSH measurements were obtained 1-28 days post L-T3 withdrawal. Three patients had to be rescheduled due to inadequate TSH levels, including one after 14 days L-T3 withdrawal. CONCLUSION: TSH levels ≥30 µIU/mL were achieved at 3 weeks post thyroidectomy or after L-T4 withdrawal and after at least 2 weeks following L-T3 cessation.

Imaging Pediatric Plasmacytoid Dendritic Cell Neoplasm With FDG PET/CT: Atypical Presentation of a Rare Disease.

Blastic plasmacytoid dendritic cell neoplasm is a rare malignancy characterized by cutaneous involvement and hematological dissemination. Most affected patients are older, usually in the sixth or seventh decade of life, and this condition has rarely been described in the pediatric population. This report presents the case of a 9-year-old boy with blastic plasmacytoid dendritic cell neoplasm and demonstrates the utility of FDG PET/CT for staging and treatment follow-up.

Isolated thymic Langerhans cell histiocytosis discovered on F-18 fluorodeoxyglucose positron emission tomography/computed tomography (F-18 FDG PET/CT).

The thymic infiltration in young patients with multisystemic Langerhans cell histiocytosis and its radiologic features are well known. However, isolated thymic disease has seldom been reported in the literature. We report the case of a 10-month-old child admitted for fever of unknown origin. Whole-body F-18 fluorodeoxyglucose positron emission tomography/computed tomography (F-18 FDG PET/CT) was performed to identify a focus of infection. It demonstrated an unusual aspect of the thymus, which led to further investigation and revealed isolated infiltration of the thymus by Langerhans cell histiocytosis. The patient was treated accordingly and is now disease free. As evaluation of Langerhans cell histiocytosis patients with F-18 FDG PET/CT is becoming more frequent, it is important to be aware of the scintigraphical characteristics of thymic Langerhans cell histiocytosis.

Cumulative doses of adjunct 131I treatment depend on location of residual thyroid tissue after total thyroidectomy in differentiated thyroid cancer.

PURPOSE: The aim of this study was to review the outcome after adjunct postoperative 131I therapy in patients with differentiated thyroid carcinoma (DTC) treated with total thyroidectomy (excluding medullary thyroid carcinoma). METHODS: Retrospective chart review: Management protocol is total thyroidectomy with cervical node sampling, 131I whole-body scan 3 weeks postoperatively to document residual thyroid tissue or metastatic lesions. Adjunct treatment consists of one or more 131I (100-200 mci/1.73 m2). Patients are considered disease free if 2 consecutive 131I whole-body scan are negative with undetectable thyroglobulin level. RESULTS: Twenty-one patients, 14 females and 7 males, with a mean age of 13.6 years were treated. Whole-body scan postoperatively revealed uptake in the thyroid bed (TB) in 10 patients, in cervical lymph nodes (CLN) in 9 patients, and in CLN and lungs in 2 patients. Patients with residual uptake in TB received a significantly lesser dose of 131I (mean, 122 +/- 53 mci) than those with metastatic CLN (357 +/- 182 mci) (P < .004) (t test) or lung mets (523.5 mci). With a mean follow-up of 7.8 years (range, 1-16 years), overall survival is 100% but disease-free survival is 100%, 66%, and 0% respectively for patients with residual disease in TB, CLN, and lungs. CONCLUSION: Patient with residual thyroid tissue in the TB required a significantly lesser number of treatments and doses of 131I compared to patients with cervical node metastases with a 100% disease-free survival. The best management of immediate postoperative residual cervical nodes (surgical excision vs 131I) remains to be defined. The efficacy of 131I therapy in patients with lung metastases remains controversial with complete remission unlikely.

Normal glomerular filtration rate in long-term follow-up of children after orthotopic liver transplantation.

BACKGROUND: Cyclosporine A (CyA) and tacrolimus are the principal immunosuppressive agents used for OLT in children. However, progressive deterioration of renal function from calcineurin inhibitor toxicity after OLT has been widely reported. The aim of this study was to assess long-term renal function in children after OLT. METHODS: We reviewed all OLT patients surviving >1 year at Sainte Justine Hospital from 1987 to 2003. The GFR (ml/min/1.73 m) was measured yearly by the Tc-99m DTPA single injection technique RESULTS: In all, 101 OLT patients (27 tyrosinemia, 33 biliary atresia, 5 fulminant hepatic failure, 36 miscellaneous) were studied. Median age at OLT was 35 months (range 6-178 months) in tyrosinemia group and 58 months (range 1-226 months) in the "Others" (P = NS), median pediatric end-stage liver disease score was respectively 3 (range -9 to 21) and 15 (-9 to 35), (P=0.001), and median follow-up was 6 (range 1-14) and 6 (range 1-17) (P = NS) years, respectively. Median annual GFR values in tyrosinemia fluctuated between 61 and 104 ml/min/1.73 m, with an improving tendency, and 94-121 ml/min/1.73 m in the Others. GFR did not differ on CyA vs. tacrolimus treatment. The median duration of therapy with calcium-channel blocker in the tyrosinemia group was 5 (1-13) vs. 2 (1-13) years in the Others. CONCLUSIONS: Median GFR remained normal in most nontyrosinemia patients (Others). Tyrosinemia patients remained stable at a lower GFR. CyA administration in three daily doses and prolonged calcium-channel blocker therapy may have contributed to this stability. Impairment of kidney function was associated with congenital kidney disease, toxic kidney injury, and portal hypertension.