Notch-dependent cooperativity between myeloid lineages promotes Langerhans cell histiocytosis pathology.

Langerhans cell histiocytosis (LCH) is a potentially fatal neoplasm characterized by the aberrant differentiation of mononuclear phagocytes, driven by mitogen-activated protein kinase (MAPK) pathway activation. LCH cells may trigger destructive pathology yet remain in a precarious state finely balanced between apoptosis and survival, supported by a unique inflammatory milieu. The interactions that maintain this state are not well known and may offer targets for intervention. Here, we used single-cell RNA-seq and protein analysis to dissect LCH lesions, assessing LCH cell heterogeneity and comparing LCH cells with normal mononuclear phagocytes within lesions. We found LCH discriminatory signatures pointing to senescence and escape from tumor immune surveillance. We also uncovered two major lineages of LCH with DC2- and DC3/monocyte-like phenotypes and validated them in multiple pathological tissue sites by high-content imaging. Receptor-ligand analyses and lineage tracing in vitro revealed Notch-dependent cooperativity between DC2 and DC3/monocyte lineages during expression of the pathognomonic LCH program. Our results present a convergent dual origin model of LCH with MAPK pathway activation occurring before fate commitment to DC2 and DC3/monocyte lineages and Notch-dependent cooperativity between lineages driving the development of LCH cells.

Expanding spectrum, intrafamilial diversity, and therapeutic challenges from 15 patients with heterozygous CARD11-associated diseases: A single center experience.

CARD11-associated diseases are monogenic inborn errors of immunity involving immunodeficiency, predisposition to malignancy and immune dysregulation such as lymphoproliferation, inflammation, atopic and autoimmune manifestations. Defects in CARD11 can present as mutations that confer a complete or a partial loss of function (LOF) or contrarily, a gain of function (GOF) of the affected gene product. We report clinical characteristics, immunophenotypes and genotypes of 15 patients from our center presenting with CARD11-associated diseases. Index cases are pediatric patients followed in our immunology division who had access to next generation sequencing studies. Variant significance was defined by functional analysis in cultured cells transfected with a wild type and/or with mutated hCARD11 constructs. Cytoplasmic aggregation of CARD11 products was evaluated by immunofluorescence. Nine index patients with 9 unique heterozygous CARD11 variants were identified. At the time of the identification, 7 variants previously unreported required functional validation. Altogether, four variants showed a GOF effect as well a spontaneous aggregation in the cytoplasm, leading to B cell expansion with NF-κB and T cell anergy (BENTA) diagnosis. Additional four variants showing a LOF activity were considered as causative of CARD11-associated atopy with dominant interference of NF-kB signaling (CADINS). The remaining variant exhibited a neutral functional assay excluding its carrier from further analysis. Family segregation studies expanded to 15 individuals the number of patients presenting CARD11-associated disease. A thorough clinical, immunophenotypical, and therapeutic management evaluation was performed on these patients (5 BENTA and 10 CADINS). A remarkable variability of disease expression was clearly noted among BENTA as well as in CADINS patients, even within multiplex families. Identification of novel CARD11 variants required functional studies to validate their pathogenic activity. In our cohort BENTA phenotype exhibited a more severe and expanded clinical spectrum than previously reported, e.g., severe hematological and extra hematological autoimmunity and 3 fatal outcomes. The growing number of patients with dysmorphic facial features strengthen the inclusion of extra-immune characteristics as part of the CADINS spectrum. CARD11-associated diseases represent a challenging group of disorders from the diagnostic and therapeutic standpoint, especially BENTA cases that can undergo a more severe progression than previously described.

High prevalence of BRAFV600E in patients with cholestasis, sclerosing cholangitis or liver fibrosis secondary to Langerhans cell histiocytosis.

Targeted therapies with MAPK inhibitors have proven to modulate the clinical manifestations of patients with Langerhans cell histiocytosis (LCH). We explored the presence of BRAFV600E mutation in our cohort of patients with LCH and cholestasis, sclerosing cholangitis, or liver fibrosis that presented resistance to chemotherapy. The BRAFV600E mutation was detected either in the diagnosis (skin and bone) or liver biopsy in our cohort of 13 patients. Thus, we observed a high incidence of BRAFV600E mutation in 100% either in diagnostic biopsy (skin and bone) or liver biopsy in patients with progressive liver disease, sequela, or liver transplant requirement.

Outcomes of event-free survival in patients with Wilms tumor undergoing preoperative chemotherapy. Analysis of lymph-node yield in a single-center cohort.

INTRODUCTION: The clinical value of lymph node sampling in Wilms tumor (WT) lies in its ability to accurately determine lymph node (LN) involvement. LN yield (LNY) is used as a valuable tool to measure LN retrieval, and a minimum of 6 LNs is one of the current recommendations. In patients who are managed with the SIOP strategy, preoperative chemotherapy decreases the retrieval of LN during surgery resulting in lower LNY values. PURPOSE: To determine the mean LNY and to analyze survival outcomes in patients with WT who underwent preoperative chemotherapy at a single center. METHODS: We performed a retrospective chart review of all patients between 6 months and 12 years of age with unilateral WT who underwent preoperative chemotherapy between 2010 and 2018. Patients with bilateral WT or without preoperative chemotherapy were excluded. Collected data included: demographics, tumor volume, tumor histopathology, number of LNs collected (LNY), presence or absence of tumor in the retrieved LNs, and disease stage according to these results. Kaplan Meier curves were calculated to estimate 5-year event-free survival (EFS) and overall survival (OS). RESULTS: 95 patients with a median follow-up of 25 months were included in the study. A total of 19 patients underwent laparoscopic surgery. Mean LNY for the entire cohort was 3.26 (95% CI, 2.4-3.6; SD, 3.62). Six patients (6.3%) had at least one positive LN. The estimated 5-year OS was 89.3% (95% CI, 82.1%-96.5%). EFS was 79.8 (95% CI, 74.8%-84.8%). Recurrence rate was 20% (n: 19). Four patients (4.2%) developed local recurrence and 15 patients (15.7%) developed pulmonary recurrence. The initial mean LNY in patients that relapsed was 4.16 (95% CI, 2.2-5.8; SD: 4.18), which was higher than in patients who did not relapse (LNY: 3; 95% CI, 2.33-3.67; SD, 3.39). No recurrences or deaths occurred in the laparoscopic group. DISCUSSION: The identification of a minimum LNY (i.e. threshold) to minimize the risk of harboring occult metastatic disease has been proposed to standardize the surgical procedure. Preliminary results in this study suggest that a limited LNY with acceptable survival outcomes is a possible scenario in patients treated according to the SIOP protocol. Systematic LN sampling to reduce the rate of false negatives is still strongly recommended. CONCLUSION: Our cohort presented with a relatively low LNY compared to standard recommendations. Our EFS, however, remained acceptable. Multivariate analysis would be necessary to determine the actual role of LN sampling as an isolated prognostic factor in unilateral WT.

Laparoscopic total nephrectomy for Wilms tumor: Towards new standards of care.

INTRODUCTION: Laparoscopic total nephrectomy (LN) in malignant pediatric tumors remains controversial. For selected patients undergoing pre-operative chemotherapy in referral centers, LN has so far shown comparable results to the standard open technique. PURPOSE: To describe the inclusion criteria and preliminary results of laparoscopic nephrectomies (LN) for the treatment of unilateral Wilms tumors (WT). MATERIAL AND METHODS: Between November 2010 and January 2016, a retrospective study of patients with WT and undergoing pre-operative chemotherapy was performed. Inclusion criteria for candidates for LN were: unilateral tumors without venous invasion and central kidney localization. Tumor size and vascular thrombus were estimated with pre-operative computed tomography (CT) scan. Overall survival and recurrence rates were evaluated. RESULTS: Among 105 patients with WT, 14 underwent LN. Tumor bleeding or the lack of response to chemotherapy were not exclusion criteria. Median tumor volume for the patients undergoing LN was 71.5 cc (range 7-169). Patients with small tumors localized near the renal pole and candidates for nephron sparing surgery (NSS) were excluded. Estimated 5-year overall survival for all patients with WT during this period was 88.7% (88.1-103.1). Two patients underwent conversion. No recurrence or related death was found at a mean 32- month follow-up period. DISCUSSION: Reproducing the steps of the open nephrectomy when performing LN for malignant tumors allowed comparable oncologic results to the conventional procedure. However, upstaging of the tumor was not admissible and has become the main goal when approaching these patients laparoscopically. Preliminary results showed that the incidence of intraoperative rupture and incomplete node sampling were not an issue when comparing LN to open nephrectomy. On the other hand, LN for malignant tumors requires experience in advanced laparoscopy and oncologic surgery. Pre-operative chemotherapy changes the tumor's consistency and this is the key point as to why these patients are amenable to be approached laparoscopically. Lifting the tumor along with the fat to avoid capsule fraction, as well as changing the lens to the lateral port to achieve a correct view for lymph node sampling are some of the considerations when performing LN. CONCLUSIONS: Preliminary data suggest that LN for WT is feasible and has promising results in terms of event-free and overall survival. In patients undergoing pre-operative chemotherapy the correct selection for LN is crucial. Following the basic oncological precepts and in experienced centers, LN represents a plausible modality in the care of these patients.

[Pediatric adamantinoma. Case report]. / Adamantinoma en pediatría. Presentación de caso.

Adamantinoma is a primary tumor of long bones, which affects mainly the shaft of the tibia, and is extremely rare in pediatrics. It frequently presents during the second decade of life, with a slight predominance in males. It is a low grade tumor, with local aggressiveness and low rate of metastasis and recurrence once it is completely removed. Its diagnosis is difficult, not only because it is a rare disease in children, but also because of the difficulty in the differential diagnosis with other benign lesions. We report the case of a 15-year-old patient with a painless swelling of the distal tibia, whose diagnosis was confirmed with the piece of amputation, as imaging features and both initial biopsies were not enough to achieve diagnosis. Though most of the literature consists of case reports, and very few in pediatric patients, they all agree on the difficulty in achieving the diagnosis of adamantinoma.

Adamantinoma en pediatría: Presentación de caso / Pediatric adamantinoma: Case report

El adamantinoma es un tumor primario de los huesos largos, que afecta principalmente la diálisis de la tibia, y es extremadamente raro en pediatría. Se presenta a partir de la segunda década de vida, con un ligero predominio en el sexo masculino. Se trata de un tumor de bajo grado, con alta agresividad a nivel local y bajo índice de metástasis y recurrencia una vez resecado en forma completa. Su diagnóstico resulta difícil, no solo por tratarse de una patología poco frecuente en pediatría, sino también por la dificultad para el diagnóstico diferencial con otras lesiones benignas. Presentamos el caso de un paciente de 15 años, con una tumoración indolora de larga evolución en la tibia distal, cuyo diagnóstico fue confirmado histológicamente con la pieza de amputación, ya que los estudios complementarios y las dos biopsias iniciales no fueron concluyentes. Aunque la mayoría de la bibliografía publicada consta de reportes de casos, y muy pocos en pacientes pediátricos, es de común acuerdo la dificultad para arribar al diagnóstico de adamantinoma.

Adamantinoma is a primary tumor of long bones, which affects mainly the shaft of the tibia, and is extremely rare in pediatrics. It frequently presents during the second decade of life, with a slight predominance in males. It is a low grade tumor, with local aggressiveness and low rate of metastasis and recurrence once it is completely removed. Its diagnosis is difficult, not only because it is a rare disease in children, but also because of the difficulty in the differential diagnosis with other benign lesions. We report the case of a 15-year-old patient with a painless swelling of the distal tibia, whose diagnosis was confirmed with the piece of amputation, as imaging features and both initial biopsies were not enough to achieve diagnosis. Though most of the literature consists of case reports, and very few in pediatric patients, they all agree on the difficulty in achieving the diagnosis of adamantinoma.

Adamantinoma en pediatría: Presentación de caso / Pediatric adamantinoma: Case report

El adamantinoma es un tumor primario de los huesos largos, que afecta principalmente la diálisis de la tibia, y es extremadamente raro en pediatría. Se presenta a partir de la segunda década de vida, con un ligero predominio en el sexo masculino. Se trata de un tumor de bajo grado, con alta agresividad a nivel local y bajo índice de metástasis y recurrencia una vez resecado en forma completa. Su diagnóstico resulta difícil, no solo por tratarse de una patología poco frecuente en pediatría, sino también por la dificultad para el diagnóstico diferencial con otras lesiones benignas. Presentamos el caso de un paciente de 15 años, con una tumoración indolora de larga evolución en la tibia distal, cuyo diagnóstico fue confirmado histológicamente con la pieza de amputación, ya que los estudios complementarios y las dos biopsias iniciales no fueron concluyentes. Aunque la mayoría de la bibliografía publicada consta de reportes de casos, y muy pocos en pacientes pediátricos, es de común acuerdo la dificultad para arribar al diagnóstico de adamantinoma.(AU)

Adamantinoma is a primary tumor of long bones, which affects mainly the shaft of the tibia, and is extremely rare in pediatrics. It frequently presents during the second decade of life, with a slight predominance in males. It is a low grade tumor, with local aggressiveness and low rate of metastasis and recurrence once it is completely removed. Its diagnosis is difficult, not only because it is a rare disease in children, but also because of the difficulty in the differential diagnosis with other benign lesions. We report the case of a 15-year-old patient with a painless swelling of the distal tibia, whose diagnosis was confirmed with the piece of amputation, as imaging features and both initial biopsies were not enough to achieve diagnosis. Though most of the literature consists of case reports, and very few in pediatric patients, they all agree on the difficulty in achieving the diagnosis of adamantinoma.(AU)

Adamantinoma en pediatría: Presentación de caso / Pediatric adamantinoma: Case report

El adamantinoma es un tumor primario de los huesos largos, que afecta principalmente la diálisis de la tibia, y es extremadamente raro en pediatría. Se presenta a partir de la segunda década de vida, con un ligero predominio en el sexo masculino. Se trata de un tumor de bajo grado, con alta agresividad a nivel local y bajo índice de metástasis y recurrencia una vez resecado en forma completa. Su diagnóstico resulta difícil, no solo por tratarse de una patología poco frecuente en pediatría, sino también por la dificultad para el diagnóstico diferencial con otras lesiones benignas. Presentamos el caso de un paciente de 15 años, con una tumoración indolora de larga evolución en la tibia distal, cuyo diagnóstico fue confirmado histológicamente con la pieza de amputación, ya que los estudios complementarios y las dos biopsias iniciales no fueron concluyentes. Aunque la mayoría de la bibliografía publicada consta de reportes de casos, y muy pocos en pacientes pediátricos, es de común acuerdo la dificultad para arribar al diagnóstico de adamantinoma.(AU)

Adamantinoma is a primary tumor of long bones, which affects mainly the shaft of the tibia, and is extremely rare in pediatrics. It frequently presents during the second decade of life, with a slight predominance in males. It is a low grade tumor, with local aggressiveness and low rate of metastasis and recurrence once it is completely removed. Its diagnosis is difficult, not only because it is a rare disease in children, but also because of the difficulty in the differential diagnosis with other benign lesions. We report the case of a 15-year-old patient with a painless swelling of the distal tibia, whose diagnosis was confirmed with the piece of amputation, as imaging features and both initial biopsies were not enough to achieve diagnosis. Though most of the literature consists of case reports, and very few in pediatric patients, they all agree on the difficulty in achieving the diagnosis of adamantinoma.(AU)

Adamantinoma en pediatría. Presentación de caso. / [Pediatric adamantinoma. Case report].

Adamantinoma is a primary tumor of long bones, which affects mainly the shaft of the tibia, and is extremely rare in pediatrics. It frequently presents during the second decade of life, with a slight predominance in males. It is a low grade tumor, with local aggressiveness and low rate of metastasis and recurrence once it is completely removed. Its diagnosis is difficult, not only because it is a rare disease in children, but also because of the difficulty in the differential diagnosis with other benign lesions. We report the case of a 15-year-old patient with a painless swelling of the distal tibia, whose diagnosis was confirmed with the piece of amputation, as imaging features and both initial biopsies were not enough to achieve diagnosis. Though most of the literature consists of case reports, and very few in pediatric patients, they all agree on the difficulty in achieving the diagnosis of adamantinoma.

Inflammatory myofibroblastic tumor of the lung in children: anaplastic lymphoma kinase (ALK) expression and clinico-pathological correlation.

The inflammatory myofibroblastic tumor (IMT) is a rare neoplastic lesion with a high incidence in children and young people, and may arise in lungs, soft tissue, or viscera. It is recognized as a borderline tumor with the possibility to recur, undergo malignant transformation, and metastasize. IMT is composed of fascicles of bland myofibroblastic cells admixed with an inflammatory infiltrate consisting of lymphocytes, plasma cells, and eosinophils. We reviewed pulmonary IMT diagnosed at Garrahan Hospital in Buenos Aires, Argentina, during 12 years and examined the clinical, laboratory, and pathological features as well as molecular genetics. Eight pediatric cases were evaluated with a male-to-female ratio of 5:3 and a median age of 6 years at diagnosis. The most common lung localization was the upper lobe. All cases underwent surgical excision and no local recurrences were found. Five out of eight patients, including two cases with metastatic/multifocal lesions in the central nervous system (CNS), are alive and disease free after a median follow-up of 30 months. Anaplastic lymphoma kinase (ALK) expression was negative in all pulmonary samples by immunohistochemistry (IHC), however, rearrangement for ALK locus by fluorescence in situ hybridization was found in one lung and in two CNS samples. These findings may reflect higher sensitivity of the molecular biologic procedure compare to traditional IHC practice. In our pediatric experience, 25% of patients with lung IMT developed CNS lesions; therefore we consider that CNS screening in these patients should be considered, at diagnosis and later during follow up.

Detection of N-glycolyl GM3 ganglioside in neuroectodermal tumors by immunohistochemistry: an attractive vaccine target for aggressive pediatric cancer.

The N-glycolylated ganglioside NeuGc-GM3 has been described in solid tumors such as breast carcinoma, nonsmall cell lung cancer, and melanoma, but is usually not detected in normal human cells. Our aim was to evaluate the presence of NeuGc-GM3 in pediatric neuroectodermal tumors by immunohistochemistry. Twenty-seven archival cases of neuroblastoma and Ewing sarcoma family of tumors (ESFT) were analyzed. Formalin-fixed, paraffin-embedded tumor samples were cut into 5 µm sections. The monoclonal antibody 14F7, a mouse IgG1 that specifically recognizes NeuGc-GM3, and a peroxidase-labeled polymer conjugated to secondary antibodies were used. Presence of NeuGc-GM3 was evident in 23 of 27 cases (85%), with an average of about 70% of positive tumors cells. Immunoreactivity was moderate to intense in most tumors, showing a diffuse cytoplasmic and membranous staining, although cases of ESFT demonstrated a fine granular cytoplasmic pattern. No significant differences were observed between neuroblastoma with and without NMYC oncogene amplification, suggesting that expression of NeuGc-GM3 is preserved in more aggressive cancers. Until now, the expression of N-glycolylated gangliosides in pediatric neuroectodermal tumors has not been investigated. The present study evidenced the expression of NeuGc-GM3 in a high proportion of neuroectodermal tumors, suggesting its potential utility as a specific target of immunotherapy.

Detection and characterization of N-glycolyated gangliosides in Wilms tumor by immunohistochemistry.

Gangliosides are glycolipids present on the cell surface. The N-glycolylated ganglioside NeuGc-GM3 has been described in some neoplasms, such as breast carcinoma and melanoma, but is usually not detected in normal human cells. Our aim was to evaluate the presence of NeuGc-GM3 in Wilms tumor by immunohistochemistry. Postchemotherapy tumors were grouped into different histologic subtypes considering the main preserved component. Formalin-fixed, paraffin-embedded tumor samples were cut into 5-microm sections. The monoclonal antibody 14F7, a mouse IgG1 that specifically recognizes NeuGc-GM3, and a peroxidase-labeled polymer conjugated to secondary antibodies were used. Sections from breast carcinoma were employed as positive controls. Presence of NeuGc-GM3 was evident in 22 of 25 (88%) cases. The staining was stronger in the epithelial component, with a membrane pattern and cytoplasmic diffusion. The stromal component expressed cytoplasmic NeuGc-GM3 in cells with rhabdomyoblastic differentiation. Tubules of adjacent renal tissue were also positive, but no expression of NeuGc-GM3 was detected in nontumoral fetal kidney. Until now, the expression of N-glycolylated gangliosides in pediatric solid tumors has not been investigated. The present study evidenced the expression of NeuGc-GM3 in a high proportion of Wilms tumors, suggesting its potential utility as a specific target of immunotherapy.