Schwannian and Perineuriomatous Differentiation in a Series of Giant Congenital Melanocytic Nevi.

ABSTRACT: Close relationship between melanocytes and neural cells is accepted to reflect their common derivation from the neural crest and tumors combining both elements. We present a series of 10 patients with giant congenital melanocytic nevi (CMN) in which a secondary proliferation (11 lesions) with schwannian and/or perineuriomatous differentiation developed in the course of the disease. The age of the patients (4 male and 6 female) at the time of surgery and histological assessment varied from 3 months to 57 years. Histopathologically, the following subgroups were delineated: (1) nodular/tumoriform "neurotization" in CMN, (2) diffuse neurofibroma-like proliferation within CMN, (3) plexiform neurofibroma-like proliferation within CMN, and (4) diffuse perineuriomatous (hybrid schwannomatous-perineuriomatous) differentiation in CMN. We review the pertinent literature, including the role of recently identified Schwann cell precursors which are believed to represent the nerve-associated state of neural crest-like cells that persists into later developmental stages.

Pelvic Neuroblastoma of the Pediatric Prostate.

Neuroblastoma accounts for a significant portion of childhood tumors and can present in a variety of ways. Pelvic neuroblastoma has been reported but few cases exist of neuroblastoma invading or originating from the bladder or prostate. We present a 4-year-old patient with pelvic neuroblastoma arising from the prostate and describe the medical and surgical management of this challenging case. While pelvic neuroblastoma may have an improved prognosis, this case demonstrates the challenging surgical decisions that accompany these patients to maintain quality of life while balancing oncologic efficacy of treatment.

Melanoma in infants, caused by a gene fusion involving the anaplastic lymphoma kinase (ALK).

We describe the first cases of pediatric melanoma with ALK fusion gene arising within giant congenital melanocytic nevi. Two newborn boys presented with large pigmented nodular plaques and numerous smaller satellite nevi. Additional expansile nodules developed within both nevi and invasive melanomas were diagnosed before 10 months of age in both boys. Oncogenic driver mutations in NRAS and BRAF were absent in both cases. Instead, oncogenic ZEB2::ALK fusion genes were identified in both the nevus and melanoma developing within the nevus. In both cases, tumors were noted by ultrasound in utero, demonstrated significant nodularity at birth, and progressed to melanoma in the first year of life suggesting that congenital nevi with ALK fusion genes may behave more aggressively than those with other mutations. As ALK kinase inhibitors are effective against a range of tumors with similar ALK fusion kinases, identifying ALK fusion genes in congenital melanocytic nevi may provide an opportunity for targeted therapy.

Histopathologic Changes of the Esophagus in Duchenne Muscular Dystrophy.

Duchenne muscular dystrophy (DMD) is characterized by progressive systemic muscle wasting, leading to respiratory paralysis and early death. This X-linked disease is caused by DMD mutations, encoding dystrophin.1 There is little information regarding gastrointestinal abnormalities in patients with DMD. However, since the esophageal wall includes smooth and skeletal muscle it is also vulnerable to suffering the effects of muscle wasting in patients with DMD. After finding dyskeratosis and parakeratosis restricted to the proximal and middle esophagus with distal sparing in an 18-year-old patient with DMD, we performed an archive search of a large academic hospital and identified four additional patients with DMD who had also undergone esophageal biopsy. The patients consisted of five boys, ranging from 7 to 19 years of age. Esophageal injury was present in two patients, consisting of mild esophagitis in one, and spongiosis with dyskeratosis and parakeratosis in another. These patients were both older and had been diagnosed with DMD for greater than 15 years, while the three patients with histologically normal biopsies were younger and been diagnosed with DMD for 7, 9, and 13 years, respectively. Although the data is limited and the changes are subtle, they can be explained by the underlying muscular dystrophy pathophysiology.

Alpelisib decreases nevocytes of congenital melanocytic nevi.

BACKGROUND: Multiple, large or giant congenital melanocytic nevi (CMN) are uncommon and affected patients can show progressive growth and thickening, associate neurocutaneous melanocytosis or develop melanoma. Current treatment modalities are mostly complex surgeries that frequently do not solve the disease and its risks completely. Thus, investigation on new treatment options for CMN and its complications must continue. MAPK pathway inhibitors are being investigated, also targeting PI3K-AKT. Omipalisib (PI3K inhibitor, with no indications approved yet) has been studied for CMN in vitro and in mice with promising results. However, alpelisib, a PI3K inhibitor approved with an adequate safety profile for patients with severe manifestations of PROS (PIK3CA-Related Overgrowth Spectrum), had not yet been tested for CMN. OBJECTIVE: To evaluate the effect of alpelisib in nevocytes of congenital melanocytic nevi. METHODS: Nevomelanocytic tissue samples of 10 patients were collected prospectively and, following a previously reported preclinical ex vivo model, explants were placed in organotypic culture for 5 days, with or without alpelisib. Consecutively, tissue sections were stained and using scanned images with Qupath and ImageJ softwares, representative regions from the dermis were analysed (using Wilcoxon test and Spearman's correlation). RESULTS: When comparing alpelisib-treated explants with respect to control explants, we found a decrease in cell density (p = 0.0273), in density of SOX10+ -cells (p = 0.0391) and also in the % of S-100+ area (p = 0.0078), in alpelisib samples. The three markers showed a positive correlation (p < 0.05). CONCLUSIONS: This study provides first-time evidence that alpelisib induces nevocyte reduction in CMN from patient-derived explants, probably inducted by autophagy. Alpelisib is an approved drug with an adequate safety profile used in another mosaicism affecting PI3K (PROS). Further studies are needed to evaluate its efficacy in treating CMN and potentially, their complications, either with local or systemic administration, alone or in combination.

Survival following complete resection of neuroblastoma in novel orthotopic rat xenograft model.

Neuroblastoma accounts for 15% of pediatric cancer deaths, despite multimodal therapy including surgical resection. Current neuroblastoma rodent models are insufficient for studying the impact of surgery and combination treatments, largely due to the small size of mouse models. Human neuroblastoma SK-N-BE(2) cells were injected into the left adrenal gland of 5-6-week-old RNU homozygous nude rats. Rats were either monitored by MRI until humane endpoint was reached or after 5 weeks underwent operative tumor resection, followed by monitoring for recurrence and survival. Following neuroblastoma cell implantation, the majority of tumors grew to greater than 5000 mm3 within 5.5-6.5 weeks, meeting the humane endpoint. Surgical resection was successfully done in 8 out of 9 rats, extending survival following tumor implantation from a median of 42 days to 78 days (p < 0.005). Pathology was consistent with human neuroblastoma, showing small round blue cell tumors with Homer-Wright rosettes, high mitoses and karyorrhectic index, and strong PHOX2B staining. Thus, we have established a novel orthotopic xenograft rat model of neuroblastoma and demonstrated increased survival of rats after surgical tumor resection. This model can be used for the development of surgical techniques, such as the use of intraoperative molecular imaging or assessment of combination therapies that include surgery.

Biliary atresia is associated with polygenic susceptibility in ciliogenesis and planar polarity effector genes.

BACKGROUND & AIMS: Biliary atresia (BA) is poorly understood and leads to liver transplantation (LT), with the requirement for and associated risks of lifelong immunosuppression, in most children. We performed a genome-wide association study (GWAS) to determine the genetic basis of BA. METHODS: We performed a GWAS in 811 European BA cases treated with LT in US, Canadian and UK centers, and 4,654 genetically matched controls. Whole-genome sequencing of 100 cases evaluated synthetic association with rare variants. Functional studies included whole liver transcriptome analysis of 64 BA cases and perturbations in experimental models. RESULTS: A GWAS of common single nucleotide polymorphisms (SNPs), i.e. allele frequencies >1%, identified intronic SNPs rs6446628 in AFAP1 with genome-wide significance (p = 3.93E-8) and rs34599046 in TUSC3 at sub-threshold genome-wide significance (p = 1.34E-7), both supported by credible peaks of neighboring SNPs. Like other previously reported BA-associated genes, AFAP1 and TUSC3 are ciliogenesis and planar polarity effectors (CPLANE). In gene-set-based GWAS, BA was associated with 6,005 SNPs in 102 CPLANE genes (p = 5.84E-15). Compared with non-CPLANE genes, more CPLANE genes harbored rare variants (allele frequency <1%) that were assigned Human Phenotype Ontology terms related to hepatobiliary anomalies by predictive algorithms, 87% vs. 40%, p <0.0001. Rare variants were present in multiple genes distinct from those with BA-associated common variants in most BA cases. AFAP1 and TUSC3 knockdown blocked ciliogenesis in mouse tracheal cells. Inhibition of ciliogenesis caused biliary dysgenesis in zebrafish. AFAP1 and TUSC3 were expressed in fetal liver organoids, as well as fetal and BA livers, but not in normal or disease-control livers. Integrative analysis of BA-associated variants and liver transcripts revealed abnormal vasculogenesis and epithelial tube formation, explaining portal vein anomalies that co-exist with BA. CONCLUSIONS: BA is associated with polygenic susceptibility in CPLANE genes. Rare variants contribute to polygenic risk in vulnerable pathways via unique genes. IMPACT AND IMPLICATIONS: Liver transplantation is needed to cure most children born with biliary atresia, a poorly understood rare disease. Transplant immunosuppression increases the likelihood of life-threatening infections and cancers. To improve care by preventing this disease and its progression to transplantation, we examined its genetic basis. We find that this disease is associated with both common and rare mutations in highly specialized genes which maintain normal communication and movement of cells, and their organization into bile ducts and blood vessels during early development of the human embryo. Because defects in these genes also cause other birth defects, our findings could lead to preventive strategies to lower the incidence of biliary atresia and potentially other birth defects.

The improving Medication Adherence in Adolescents and young adults following Liver Transplantation (iMALT) multisite trial: Design and trial implementation considerations.

BACKGROUND/AIMS: Medication non-adherence is a leading cause of transplant rejection, organ loss, and death; yet no rigorous controlled study to date has shown compelling clinical benefits from an adherence-improving intervention. Non-adherent patients are less likely to participate in trials, and therefore, most studies enroll a majority of adherent patients who do not stand to benefit from the intervention, as they do not have the condition (non-adherence) under investigation. The improving Medication Adherence in adolescent Liver Transplant recipients trial specifically targets non-adherent patients to investigate whether a remote intervention to improve adherence results in reduced incidence of biopsy-confirmed rejection. METHODS: Improving Medication Adherence in adolescent Liver Transplant is a randomized single-blind controlled multisite, multinational National Institutes of Health-funded trial involving 13 pediatric transplant centers in the United States and Canada. An innovative, objective adherence biomarker-the Medication Level Variability Index, which is the standard deviation of a series of medication blood levels for each patient, is used to identify non-adherent patients at risk for rejection. The index is computed using electronic health record information for all potentially eligible patients based on repeated reviews of the entire clinic's roster. Identified patients, after consent, are randomized to intervention versus control (treatment as usual) arms. The remote intervention is delivered for 2 years by trained interventionists who reside in various locations in the United States. The primary outcome is the incidence of biopsy-confirmed acute cellular rejection, as confirmed by a majority vote of three pathologists who are masked to the study allocation and clinical information. DISCUSSION: Improving Medication Adherence in adolescent Liver Transplant includes several innovative design elements. The use of a validated, objective adherence index to survey a large cohort of transplant recipients allows the teams to avoid bias inherent in both convenience sampling and referral-based recruitment and enroll only patients whose computed index indicates substantially increased risk of rejection. The remote intervention paradigm helps to engage patients who are by definition hard to engage. The use of an objective, masked medical (rather than behavioral) outcome measure reduces the likelihood of biases related to clinical information and ensures broad acceptance by the field. Finally, monitoring for potential adverse events related to increased medication exposure due to the adherence intervention acknowledges that a successful intervention (increasing adherence) could have detrimental side effects via increased exposure to and potential toxicity of the medication. Such monitoring is almost never attempted in clinical trials evaluating adherence interventions.

Mesotheliomas in Children.

Mesotheliomas are rare and aggressive tumors that originate from mesothelial cells. Although exceedingly rare, these tumors may occur in children. Different from adult mesotheliomas, however, environmental exposures particularly to asbestos do not appear to play a major role in mesotheliomas in children, in whom specific genetic rearrangements driving these tumors have been identified in recent years. These molecular alterations may increasingly offer opportunities for targeted therapies in the future, which may provide better outcomes for these highly aggressive malignant neoplasms.

Pediatric BCOR-Altered Tumors From Soft Tissue/Kidney Display Specific DNA Methylation Profiles.

In the pediatric population, BCL6-correpresor gene (BCOR)-upregulated tumors include primitive myxoid mesenchymal tumors/undifferentiated sarcomas (PMMTI/UND), clear cell sarcomas of the kidney (CCSK), and high-grade neuroepithelial tumors (HG-NET). We investigated DNA methylation (DNAm) and copy number variation (CNV) profiling in these tumors (N = 34) using an Illumina EPIC BeadChip to better define the potential use of these tools to confirm diagnosis and predict outcomes. Twenty-seven tumors from 25 patients (age range, 0-10 years), showed molecular confirmation of genetic abnormalities as follows: BCOR internal tandem duplication in 14 PMMTI/UND, 8 CCSK, and 3 HG-NET and YWHAE fusions in 2 PMMTI/UND. The remaining 7 cases lacking informative molecular data were analyzed by immunophenotyping and were included in the study as a training cohort, clearly separated from the main study group. These were 4 PMMTI, 1 HG-NET, and 1 CCSK in which poor RNA preservation precluded the confirmation of BCOR rearrangements and 1 CCSK in which no rearrangements were found. DNAm data were compared with those of brain tumor and/or sarcoma classifier. Differentially methylated regions (DMRs) were analyzed in the 3 groups. Twenty-two cases of the 24 molecularly confirmed PMMTI/UND and CCSK and 3 of 6 of those with only immunophenotyping were classified within the methylation class "BCOR-altered sarcoma family" with optimal calibrated scores. PMMTI/UND and CCSK showed similar methylation profiles, whereas thousands of DMRs and significantly enriched pathways were evident between soft tissue/kidney tumors and HG-NET. The CNV analysis showed an overall flat profile in 19 of the 31 evaluable tumors (8/10 CCSK; 9/18 PMMTI/UND; 2/4 HG-NET). The most frequent CNVs were 1q gain and 9p and 10q loss. Follow-up time data were available for 20 patients: ≥2 CNV significantly correlated with a worse overall survival rate. In conclusion, soft tissue and kidney BCOR sarcomas matched with BCOR-altered sarcoma methylation class, whereas those from the brain matched with the central nervous system tumor classifier HG-NET BCOR, supporting the notion that DNAm profiling is an informative diagnostic tool. CNV alterations were associated with a more aggressive clinical behavior.

Morphologic and Ancillary Studies of Pediatric Acinic Cell Carcinoma: A Single Institute Experience.

BACKGROUND: Acinic cell carcinoma (AciCC) is the second most common pediatric malignant salivary gland tumor. However, there are limited pathology publications about this tumor in the pediatric population. METHODS: We describe four pediatric AciCC cases diagnosed between 2000 and 2021 in our institute. Reticulin histochemistry plus immunohistochemistry for NR4A3 and DOG1 were performed on all cases. RESULTS: Histologically, all four cases featured a tumor-associated lymphoid proliferation and collagenous stroma, in which two formed central scars. The tumors were predominantly solid, with a lobular pattern and variably sized dilated spaces, including one case with focal microcysts. High-grade transformation was not observed in any of our cases. Reticulin stain and immunohistochemistry for NR4A3 showed distinct features between AciCC and non-neoplastic salivary gland parenchyma. DOG1 immunohistochemistry confirmed the acinar origin of AciCC. CONCLUSIONS: Our study reveals that pediatric AciCCs often present with tumor-associated lymphoid proliferation (TALP) and sclerosis. Special stains such as reticulin histochemistry and NR4A3 immunohistochemistry are helpful to separate tumor from adjacent benign parenchyma. The ancillary study is helpful for the diagnosis of small specimens. Our study is limited by its low case number, but we hope that our results will promote more studies on this rare salivary gland tumor in the pediatric population.

Operational tolerance after intestine re-transplantation in childhood and immunological correlates. Case report and review.

BACKGROUND: Operational tolerance after retransplantation of the intestine has never been reported. PURPOSE: To two recently described intestine transplant recipients with operational tolerance, we now add a third. METHODS: Review of case record and immunological testing to confirm donor-specific hyporesponsiveness in multiple immune cell compartments. RESULTS: Re-transplanted with a multivisceral liver- and kidney-inclusive intestine allograft at age 12 years, this recipient self-discontinued immunosuppression 14 years after the retransplant and has been rejection free for 2 years thereafter. As in the two previous reports, immunological testing demonstrated decreased donor-specific inflammatory response of T-cytotoxic memory cells and B-cells, decreased presentation of donor antigen by B-cells and monocytes, absence of donor-specific anti-HLA antibodies, circulating FOXP3 + T-helper cells, and intact cellular and humoral immunity to cytomegalovirus and Epstein-Barr virus. Additionally, our recipient demonstrated enhanced donor-activation-induced apoptosis of alloreactive T-cytotoxic memory cells. CONCLUSIONS: Despite variable paths to tolerance which include graft versus host disease in two previous cases, and rejection-related loss of the primary isolated intestinal allograft in our recipient, the three cases with operational tolerance are bound by common themes: a relatively large donor antigenic load transmitted during intestine transplantation, and donor-specific hyporesponsiveness. Cell-based assays suggest enhanced donor-induced apoptosis of recipient T-cells and circulating T-regulatory cells as mechanistic links between antigenic load and donor-specific hyporesponsiveness.

Potter Deformation Sequence Caused by 17q12 Deletion: A Lethal Constellation.

17q12 deletion syndrome causes developmental abnormalities of the kidneys, pancreas, genital tract, and neurodevelopment, and it has a wide range of phenotypes ranging from fetal demise to normal adulthood with minimal renal impairment. Here we describe a rare case of 17q12 deletion diagnosed prenatally, complicated by anhydramnios and Potter sequence. The baby was born but necessitated life-saving interventions due to pulmonary and renal insufficiency and ultimately succumbed to multi-organ failure. We present full autopsy results describing findings linked to 17q12 deletion, including severe bilateral multicystic renal dysplasia, pancreatic hypoplasia, and cysts adjacent to the Fallopian tubes. We also describe pulmonary hypoplasia and Potter facies as consequences of anhydramnios. We correlate these findings to our current understanding of molecular signals altered by 17q12 deletion, notably affecting HNF1B and LHX1 genes, which are known to mediate renal and genitourinary tract development.

A non-human primate model of acute liver failure suitable for testing liver support systems.

Acute hepatic failure is associated with high morbidity and mortality for which the only definitive therapy is liver transplantation. Some fraction of those who undergo emergency transplantation have been shown to recover native liver function when transplanted with an auxiliary hepatic graft that leaves part of the native liver intact. Thus, transplantation could have been averted with the development and use of some form of hepatic support. The costs of developing and testing liver support systems could be dramatically reduced by the availability of a reliable large animal model of hepatic failure with a large therapeutic window that allows the assessment of efficacy and timing of intervention. Non-lethal forms of hepatic injury were examined in combination with liver-directed radiation in non-human primates (NHPs) to develop a model of acute hepatic failure that mimics the human condition. Porcine hepatocyte transplantation was then tested as a potential therapy for acute hepatic failure. After liver-directed radiation therapy, delivery of a non-lethal hepatic ischemia-reperfusion injury reliably and rapidly generated liver failure providing conditions that can enable pre-clinical testing of liver support or replacement therapies. Unfortunately, in preliminary studies, low hepatocyte engraftment and over-immune suppression interfered with the ability to assess the efficacy of transplanted porcine hepatocytes in the model. A model of acute liver failure in NHPs was created that recapitulates the pathophysiology and pathology of the clinical condition, does so with reasonably predictable kinetics, and results in 100% mortality. The model allowed preliminary testing of xenogeneic hepatocyte transplantation as a potential therapy.

Addressing the diagnostic and therapeutic dilemmas of ovarian immature teratoma: Report from a clinicopathologic consensus conference.

Ovarian immature teratoma is a rare subtype of germ cell tumour that can be pure or associated with non-teratomatous germ cell tumour elements and is graded based on extent of the immature neuroectodermal component. Immature teratoma (IT) can also be associated with somatic differentiation in the form of sarcoma, carcinoma, or extensive immature neuroectodermal elements and may produce low levels of serum alpha-fetoprotein. Variable interpretation of these issues underlies diagnostic and management dilemmas, resulting in substantial practice differences between paediatric and adult women with IT. The Malignant Germ Cell International Consortium (MaGIC) convened oncologists, surgeons, and pathologists to address the following crucial clinicopathologic issues related to IT: (1) grading of IT, (2) definition and significance of 'microscopic' yolk sac tumour, (3) transformation to a somatic malignancy, and (4) interpretation of serum tumour biomarkers. This review highlights the discussion, conclusions, and suggested next steps from this clinicopathologic conference.

Congenital Teratocarcinosarcoma With CTNNB1 Gene Mutation Presenting as an Ocular Mass.

Teratocarcinosarcoma is an extremely rare malignancy of the nasal cavity and paranasal sinuses. It exhibits both sarcomatous and carcinomatous components. Less than 100 cases are reported. It presents in adults with only two reported cases in infancy. Here we present a case of 3-week-old female with antenatally detected ocular mass. MRI revealed an exophytic right ocular mass (10 × 7.0 × 7.0 cm) with intracranial extension. The tumor consisted of malignant glands and mesenchymal elements of undifferentiated blastema-like cells and immature neuroepithelium. After an initial diagnosis and treatment for a Wilms tumor protocol, the mass showed no response. A second opinion rendered a diagnosis of sinonasal teratocarcinosarcoma. The patient underwent surgical resection and seven cycles of CNS ICE chemotherapy. A second debulking surgery revealed a very scant viable tumor with post-treatment changes. The patient is alive at 43 months on weekly vincristine maintenance. Molecular testing revealed a somatic CTNNB1 gene mutation. In conclusion, this is a rare and aggressive tumor which showed disease free survival beyond that reported in the literature with the appropriate use of multimodality therapy.

Calyceal diverticula: Clinical, radiological and histopathological findings of an uncommon entity with presumed congenital origin.

Calyceal diverticula (CD) are relatively uncommon urologic conditions that generally follow an asymptomatic course and rarely require medical intervention. CD are thought to have a congenital origin due to abnormalities during the process of ureteral bud formation. Clinically and radiologically, they can mimic multiple neoplastic and non-neoplastic renal processes, with potentially relevant differences in the management of these patients. Symptoms are usually associated with the presence of stones, obstruction to the drainage of the diverticulum, large size, or secondary infection. In chronic cases, surgery might become necessary, creating an opportunity to examine the histopathological characteristics of this condition. Although these are benign in the majority of patients, some rare instances of malignancy arising from the CD have been reported. In this series, we addressed the clinical, radiological, and histopathological findings of CD.