The Variable Definition of "Negative Appendicitis" Remains a Surgical Challenge.

AIM: Acute appendicitis (AA) is treated primarily surgically with histopathology being the gold standard for confirmation of appendicitis and reported rates of negative appendicectomies (NA) ranging between 3.2% and 19% worldwide and 15.9-20.6% in the UK. NA rates are frequently used to identify poor performing centers as part of a Model Health System and form an integral part of appendicitis scoring systems. This study aims to evaluate the prevalence of negative appendicectomies within our institution and critically analyze the appropriateness of its use as a quality metric and its impact on clinical practice and research. PATIENTS AND METHODS: Data analysis from a prospective dataset of pediatric appendicitis patients between 2015 and 2021 in a tertiary center in the UK was performed. Detailed analysis of negative appendicectomies was performed and further stratified by two distinct age and gender groups looking at the incidence of NA and the classification of non-histologically normal appendix specimens. RESULTS: In our series, 819 patients met inclusion criteria, 736 (89.9%) had acute appendicitis. Our overall institutional negative appendicectomy rate was 10.1% (83 patients) with the breakdown as follows: 65 histologically normal appendix (7.9%), 10 Enterobius vermicularis, 3 eosinophilic appendicitis, 2 neoplasms, 1 isolated faecolith, 1 fibrous obliteration of the lumen, and 1 peri-appendiceal inflammation. CONCLUSION: Our negative appendicectomy rate is below established UK pediatric NA rates. This rate ranges from 7.9% to 10.1% depending on the definition of NA utilized. A single standard pathological definition for histological acute appendicitis is required when being used as a comparative quality metric. Centers engaged in clinical research should be aware of variations in NA definitions both in scoring systems and individual centers to avoid skewing derived results.

Optic Nerve Germinoma and Transient Spontaneous Regression-More Than Meets the Eye.

Infiltration of the optic pathway by germ cell tumors is exceptional and can lead to confusion with glioma or inflammatory conditions. We present the case of a 14-year-old girl with an optic nerve germinoma extending to the hypothalamus and manifesting as panhypopituitarism and visual loss. The patient experienced spontaneous regression of the lesion followed by secondary deterioration requiring treatment. Four other cases of spontaneously regressing intracranial germinoma followed by regrowth have been reported in the literature. This report highlights the importance of clinical and radiologic monitoring of intracranial germinoma, even in the event of initial spontaneous improvement.

Genetic Diagnosis of Retinoblastoma Using Aqueous Humour-Findings from an Extended Cohort.

The identification of somatic RB1 variation is crucial to confirm the heritability of retinoblastoma. We and others have previously shown that, when tumour DNA is unavailable, cell-free DNA (cfDNA) derived from aqueous humour (AH) can be used to identify somatic RB1 pathogenic variation. Here we report RB1 pathogenic variant detection, as well as cfDNA concentration in an extended cohort of 75 AH samples from 68 patients. We show cfDNA concentration is highly variable and significantly correlated with the collection point of the AH. Cell-free DNA concentrations above 5 pg/µL enabled the detection of 93% of known or expected RB1 pathogenic variants. In AH samples collected during intravitreal chemotherapy treatment (Tx), the yield of cfDNA above 5 pg/µL and subsequent variant detection was low (≤46%). However, AH collected by an anterior chamber tap after one to three cycles of primary chemotherapy (Dx1+) enabled the detection of 75% of expected pathogenic variants. Further limiting our analysis to Dx1+ samples taken after ≤2 cycles (Dx ≤ 2) provided measurable levels of cfDNA in all cases, and a subsequent variant detection rate of 95%. Early AH sampling is therefore likely to be important in maximising cfDNA concentration and the subsequent detection of somatic RB1 pathogenic variants in retinoblastoma patients undergoing conservative treatment.

Intra-abdominal Kaposiform hemangioendothelioma and the benefits of laparoscopic surveillance.

We report a case of a neonate presenting with the rare vascular tumor, Kaposiform hemangioendothelioma. She had a lesion arising from the left ovary with multiple intraperitoneal metastases causing small bowel obstruction. We managed this case with primary surgical resection followed by laparoscopic surveillance of the peritoneal cavity and metastectomy. The child is fit and well and free of tumor after 32 months. Neither this presentation of this tumor nor this management approach has been previously described in the literature.

Segmental ABO-incompatible liver graft from a donor after cardiac death in neonatal acute liver failure.

Segmental liver grafts from DCD in pediatric LT have been safely used even in acute liver failure situations. Furthermore, despite the risk of antibody-mediated acute rejection, some studies have also demonstrated the safety of ABO incompatible LT in infants. The use of such grafts can be beneficial by reducing the time on the transplant waiting list but they are more susceptible to initial dysfunction and there is a lack of enthusiasm to consider their use especially for an emergency LT as a life-saving procedure. In this short article, we describe the use and successful outcome in a neonate with fulminant acute liver failure secondary to neonatal hemochromatosis who received an ABO-incompatible reduced-size DCD graft.

ANCA-associated glomerulonephritis/systemic vasculitis in childhood: clinical features-outcome.

BACKGROUND: Antineutrophil cytoplasmic antibody (ANCA)-associated glomerulonephritis and systemic vasculitis (AAGNV) is uncommon in childhood. METHODS: This is a retrospective study of AAGNV cases diagnosed over a 13-year period in a tertiary pediatric nephrology department. RESULTS: Thirteen cases of AAGNV were identified: seven Wegener granulomatosis (WG) and six microscopic polyangiitis (MPA). Acute renal failure/nephrotic range proteinuria (NRP) was found in 77 % of the patients (4 with WG, all with MPA). Eleven (85 %) patients showed necrotizing glomerulonephritis (NGN), with ≥50 % crescents identified in nine patients (69 %) (4 with WG, 5 with MPA). Treatment with methylprednisolone, cyclophosphamide and plasma exchange resulted in extra-renal remission and antibody reduction in all patients and renal function improvement/stabilization in 77 % of the patients. Three patients, all without oliguria at presentation and few sclerotic lesions, had normal renal function at follow-up. Chronic kidney disease (CKD) stages 2 and 3-4 were observed in four (WG) and three (MPA) patients, respectively. Three patients (23 %) developed end stage renal disease: two were MPA patients with severe presentation (markedly impaired glomerular filtration rate, oliguria, NRP, crescentic NGN, glomerular sclerosis) and one was a WG patient with extensive interstitial fibrosis/tubular atrophy. CONCLUSIONS: Severe renal involvement was more common in children with MPA than WG. Treatment with methylprednisolone, cyclophosphamide and plasma exchange induced extra-renal remission/serological response and renal function improvement/stabilization. Markedly decreased GFR, oliguria, NRP, and chronic glomerular lesions at presentation were predictors of poor outcome.

Retroperitoneal gastric duplication cyst: a case report and literature review.

A rare case of retroperitoneal gastric duplication is reported and discussed. An intra-abdominal cyst was detected at 31 weeks gestation and was followed up prenatally as a left sided duplex kidney. Post-natal ultrasound however, showed a normal kidney, but a cyst with features of enteric duplication in the left upper quadrant adjacent and compressing the kidney. Surgery was carried out during infancy and a retroperitoneal cyst was excised that contained heterotrophic gastric mucosa.

Dissecting the Transcriptional and Chromatin Accessibility Heterogeneity of Proliferating Cone Precursors in Human Retinoblastoma Tumors by Single Cell Sequencing-Opening Pathways to New Therapeutic Strategies?

Purpose: Retinoblastoma (Rb) is a malignant neoplasm arising during retinal development from mutations in the RB1 gene. Loss or inactivation of both copies of RB1 results in initiation of retinoblastoma tumors; however, additional genetic changes are needed for the continued growth and spread of the tumor. Ex vivo research has shown that in humans, retinoblastoma may initiate from RB1-depleted cone precursors. Notwithstanding, it has not been possible to assess the full spectrum of clonal types within the tumor itself in vivo and the molecular changes occurring at the cells of origin, enabling their malignant conversion. To overcome these challenges, we have performed the first single cell (sc) RNA- and ATAC-Seq analyses of primary tumor tissues, enabling us to dissect the transcriptional and chromatin accessibility heterogeneity of proliferating cone precursors in human Rb tumors. Methods: Two Rb tumors each characterized by two pathogenic RB1 mutations were dissociated to single cells and subjected to scRNA-Seq and scATAC-Seq using the 10× Genomics platform. In addition, nine human embryonic and fetal retina samples were dissociated to single cells and subjected to scRNA- and ATAC-Seq analyses. The scRNA- and ATAC-Seq data were embedded using Uniform Manifold Approximation and Projection and clustered with Seurat graph-based clustering. Integrated scATAC-Seq analysis of Rb tumors and human embryonic/fetal retina samples was performed to identify Rb cone enriched subclusters. Pseudo time analysis of proliferating cones in the Rb samples was performed with Monocle. Ingenuity Pathway Analysis was used to identify the signaling pathway and upstream regulators in the Rb cone-enriched subclusters. Results: Our single cell analyses revealed the predominant presence of cone precursors at different stages of the cell cycle in the Rb tumors and among those identified the G2/M subset as the cell type of origin. scATAC-Seq analysis identified two Rb enriched cone subclusters, each characterized by activation of different upstream regulators and signaling pathways, enabling proliferating cone precursors to escape cell cycle arrest and/or apoptosis. Conclusions: Our study provides evidence of Rb tumor heterogeneity and defines molecular pathways that can be targeted to define new treatment strategies.

Retroperitoneal cystic lymphangioma: a rare presentation in childhood, treated laparoscopically.

Retroperitoneal cystic lymphangioma is a rare benign lesion of childhood. A 15-year-old girl underwent laparoscopic excision of such a cyst. On histopathological examination, the resection was complete. She had an uneventful recovery and remains asymptomatic. We report this in view of the rarity of this condition and also the unusual presentation of this case. Complete surgical excision via laparoscopy is a feasible option.

Human interleukin-2 receptor ß mutations associated with defects in immunity and peripheral tolerance.

Interleukin-2, which conveys essential signals for immunity, operates through a heterotrimeric receptor. Here we identify human interleukin-2 receptor (IL-2R) ß chain (IL2RB) gene defects as a cause of life-threatening immune dysregulation. We report three homozygous mutations in the IL2RB gene of eight individuals from four consanguineous families that cause disease by distinct mechanisms. Nearly all patients presented with autoantibodies, hypergammaglobulinemia, bowel inflammation, dermatological abnormalities, lymphadenopathy, and cytomegalovirus disease. Patient T lymphocytes lacked surface expression of IL-2Rß and were unable to respond to IL-2 stimulation. By contrast, natural killer cells retained partial IL-2Rß expression and function. IL-2Rß loss of function was recapitulated in a recombinant system in which IL2RB mutations caused reduced surface expression and IL-2 binding. Stem cell transplant ameliorated clinical symptoms in one patient; forced expression of wild-type IL-2Rß also increased the IL-2 responsiveness of patient T lymphocytes in vitro. Insights from these patients can inform the development of IL-2-based therapeutics for immunological diseases and cancer.

Are more of my patients developing side effects than expected?

PURPOSE: Modern radiation oncology treatments are typically associated with a certain level of acute or long-term complications. Whenever a new treatment is introduced into clinical practice, a clinician may have reason to question whether certain side effects occur more frequently in his or her patients than reported in the published literature. However, the clinician, lacking rigorous statistical methods to answer this question, may not draw the correct conclusion until treating a larger number of patients than necessary. METHODS AND MATERIALS: We propose a Bayesian framework to calculate (1) the probability that the rate of an adverse event (AE) is above a certain threshold and (2) the number of AEs to be observed before we can conclude with a certain confidence level that the AE rate is above a threshold. Both questions will be answered based on the formulation of a posterior distribution of the AE rate given the observed data. The proposed method does not rely on large sample assumptions, and the computation of the solution is quick and straightforward. The proposed methods are illustrated in 2 clinical scenarios. RESULTS: We tabulated the probability that an AE rate is greater than a threshold for a given number of patients experiencing events from an observed number of patients. In addition, we developed a free online interactive tool to facilitate the implementation of the method. CONCLUSIONS: The proposed method, including the presented tables and the online tool, provides clinicians with a practical means of determining if his or her patients are experiencing a greater (or lower) number of complications than expected. How to use the statistical result to guide a clinical decision depends upon the specifics of the clinical condition and the available treatment alternatives.