Clinicopathologic Features of Severe Acute Hepatitis Associated With Adenovirus Infection in Children

A recent increase in reports of severe acute hepatitis of unknown etiology in children is under investigation. Although adenovirus has been frequently detected, its role remains unclear, and systematic histopathologic analysis is lacking. We conducted a retrospective study of 11 children hospitalized between October 2021 and May 2022 with unexplained acute hepatitis and concurrent adenovirus infection. Liver biopsies collected shortly after admission demonstrated moderately to severely active hepatitis in 8/11 (73%) cases, characterized by marked portal mixed inflammation, moderate-to-severe interface activity, and milder lobular inflammation. Clusters of plasma cells were present in 6/11 (55%) cases, mimicking autoimmune hepatitis. Semiquantitative scoring of 17 discrete histologic features found that greater degrees of portal inflammation, interface activity, bile duct injury, bile ductular reaction, lobular inflammation, Kupffer cell activation, and hepatocyte focal necrosis were significantly more common in these cases in comparison to the control group of unexplained acute severe hepatitis without adenovirus infection. Liver biopsy immunohistochemistry was negative for adenovirus in all cases. Polymerase chain reaction testing of liver tissue was positive for the enteric adenovirus serotypes 41 (species F) in 10/11 (91%) cases. An immunoprofile study of hepatic infiltrating lymphocytes in 1 patient revealed the presence of large numbers of CD3 + and CD4 + lymphocytes. Nine patients received supportive treatment without steroids and recovered without the need for liver transplantation. In summary, liver injury in children with severe acute hepatitis and adenovirus infection is characterized by a hepatitic pattern that resembles severe autoimmune hepatitis and may represent an immune-mediated process associated with viral infection.

Gastric Antral Mucosal Changes in Children With Intestinal Metaplasia

Objectives: The gastric mucosal change accompanying gastric antral intestinal metaplasia (IM) in the pediatric population and its clinical implications remain unclear. Methods: We retrieved all patients younger than 18 years who had upper GI endoscopy with a pathology diagnosis of antral IM between 2009 and 2020. Each biopsy was evaluated for the presence of dysplasia, Helicobacter pylori, gastritis, and other pathologic changes. Results: A total of 134 patients with antral IM were identified; 72 (53.7%) with coexisting pathology including chronic gastritis (n = 22), reactive gastropathy (n = 16), focal mild chronic inflammation (n = 13), gastric eosinophilia (n = 9), chronic active gastritis associated with (n = 2) and without Helicobacter infection (n = 3), and others (n = 7). The remaining 62 (46.3%) showed isolated IM. Gastric IM increased with age, and was often accompanied by other pathologic changes, especially in female children. Twenty-seven patients had follow up biopsies; 11 of the 27 patients (40.7%) showed persistent IM in at least one repeat biopsies. None demonstrated dysplasia. Conclusions: In children, antral IM increases with age and often coexists with other pathologic changes. Gastric IM could persist for at least months to years in a significant subset of patients with chronic gastritis and gastric eosinophilia.

Bloom where you are planted: Hemangioma or malignancy?

Vascular anomalies comprise a spectrum of disorders characterized by the abnormal development or growth of blood and lymphatic vessels. These growths have unique features and diverse behaviors, mandating a multidisciplinary approach in their evaluation, diagnosis, and management. Here we describe the case of a male toddler presenting with an abdominal mass, originally treated as a metastatic retroperitoneal tumor, but subsequently felt to represent a vascular anomaly.

Therapy-related Myeloid Neoplasms in Children: A Single-institute Study

Therapy-related myeloid neoplasm (t-MN) in the pediatric population is not well characterized. We studied 12 pediatric patients diagnosed with t-MN in our institution since 2006. The median age at the t-MN diagnoses was 14.8 years (range, 9 to 20 y). The primary malignancies included 9 solid tumors and 3 hematopoietic malignancies. Rhabdomyosarcoma (n=4) was the most common primary malignancy. Five of the 9 patients with solid tumors and all 3 patients with hematopoietic malignancies had primary neoplasms involving bone marrow. The median latency period was 5.2 years (range, 1.8 to 13.8 y). Thrombocytopenia was present in all patients at the t-MN diagnoses. Complete or partial monosomy of chromosome 5 or 7 were the 2 most common cytogenetic abnormalities. A quarter of patients demonstrated a genetic predisposition to t-MN: 1 with Li-Fraumeni syndrome with a germline TP53 R248Q mutation, 1 with Noonan syndrome with a somatic mutation (PTPN11 S502T), and 1 with a constitutive chromosomal translocation [t(X;9)(p22;q34)] and a germline TP53 L130V mutation. Outcomes remain poor. Two patients survived 3 and 5.1 years after hematopoietic stem cell transplantation.

Pleuropulmonary blastoma in an adolescent

Primary pulmonary malignancies are rare in childhood. The most common, pleuropulmonary blastoma (PPB), has an incidence of 25–50 cases per year in the United States (Knight and et al., 2019) [1]. The majority of children are diagnosed with PPB before the age of four years. PPB is divided into subtypes I, Ir (type I-regressed), II, and III, which correlates to the age of diagnosis and patient prognosis [2,3]. Here we report an unusual presentation of PPB in a teen-aged female who presented with a one month history of a non-productive cough.

Prevalence of chronic rhinosinusitis in bronchiectasis patients suspected of ciliary dyskinesia

BACKGROUND

Mucociliary clearance is a main defense mechanism of the airway and is impaired in ciliary dyskinesia. The objective of this study was to evaluate the prevalence of chronic rhinosinusitis (CRS) and its characteristics in bronchiectasis patients suspected of harboring ciliary dyskinesia.

METHODS

Bronchiectasis patients referred to a rhinology clinic for nasal brush biopsy (NBB) were included in this study. NBB was performed using a curettage technique whereby ciliated epithelial cells were obtained from the surface of the inferior nasal turbinate. Results of transmission electron microscopy findings, primary ciliary dyskinesia (PCD) gene (35 genes) analyses (Invitae), and sinus computed tomography (CT) scans were reviewed.

RESULTS

Twenty-three patients (age, 54 ± 2.9 years) were referred for NBB between 2015 and 2018. Thirteen patients (56.5%) met the criteria for diagnosis of CRS. Nineteen patients had ciliary ultrastructural defects. The most common finding was compound cilia (n = 11, 47.8%). Five patients (21.7%) had central microtubule defects (CMD) with higher forced expiratory volume in 1 second (FEV₁ ) at the time of referral than those without CMD (CMD⁺ , 91 ± 3.7%; CMD^- , 73.5 ± 5.7%; p = 0.023). Of 15 subjects with a PCD gene panel, 67% (9 of 15) carried at least 1 gene associated with PCD. Only 1 patient reached diagnosis of PCD. Approximately 50% of non-PCD carriers had a smoking history (p < 0.05). Lund-Mackay scores did not significantly differ between PCD and non-PCD carriers (p = 0.72).

CONCLUSION

Nearly half of bronchiectasis patients referred for NBB had concurrent CRS. The presence of ciliary abnormalities was not amplified in bronchiectasis patients with CRS compared to those without CRS. Extrinsic factors may be related to ciliary structural abnormalities in non-PCD gene carriers.

TLE1 Expression in Malignant Rhabdoid Tumor and Atypical Teratoid/Rhabdoid Tumor

Malignant rhabdoid tumors (MRT; atypical teratoid/rhabdoid tumor [ATRT] in the central nervous system) are aggressive tumors in infants and children which can overlap with other sarcomas, such as synovial sarcoma (SS). The gold standard for SS diagnosis is characterization of the t(X;18) chromosomal translocation. However, stratification of cases for molecular analysis is not always straightforward or feasible. Recent literature suggests transducer-like enhancer of split 1 (TLE1) protein expression may distinguish SS from certain histologic mimics; however, this has not been investigated in MRT and ATRT. We stained whole-tissue sections of 18 archived cases of MRT and ATRT with TLE1. Nuclear expression was scored using a 4-tiered (0, 1+, 2+, and 3+) scale describing staining intensity, extent, or combination of both. The majority of MRT and ATRT cases showed some TLE1 immunoreactivity (n = 16; 89% for ≥1 + staining); 14 (78%) of total cases showed ≥2 + positivity using any of the 3 scoring systems. Over half (n = 10; 56%) of cases showed ≥2 + staining; 4 (22%) cases showed 3 + strong and diffuse TLE1 staining measured by all scoring systems in agreement. Although still of potential use, we urge caution in the interpretation of TLE1 when the differential diagnosis includes both SS and MRT or ATRT.

Subclinical inflammation phenotypes and long-term outcomes after pediatric kidney transplantation

The implementation of surveillance biopsies in pediatric kidney transplantation remains controversial. Surveillance biopsies detect subclinical injury prior to clinical dysfunction, which could allow for early interventions that prolong allograft survival. We conducted a single-center retrospective cohort study of 120 consecutive pediatric kidney recipients, of whom 103 had surveillance biopsies ≤6 months posttransplant. We tested the hypothesis that subclinical inflammation (borderline or T cell-mediated rejection without clinical dysfunction) is associated with a 5-year composite endpoint of acute rejection and allograft failure. Overall, 36% of subjects had subclinical inflammation, which was associated with increased hazard for the composite endpoint (adjusted hazard ratio 2.89 [1.27, 6.57]; P < .01). Subjects with treated vs untreated subclinical borderline rejection had a lower incidence of the composite endpoint (41% vs 67%; P < .001). Subclinical vascular injury (subclinical inflammation with Banff arteritis score > 0) had a 78% incidence of the composite endpoint vs 11% in subjects with no major surveillance abnormalities (P < .001). In summary, we showed that subclinical inflammation phenotypes were prevalent in pediatric kidney recipients without clinical dysfunction and were associated with increased acute rejection and allograft failure. Once prospectively validated, our data would support implementation of surveillance biopsies as standard of care in pediatric kidney transplantation.

Pediatric Anaplastic Embryonal Rhabdomyosarcoma: Targeted Therapy Guided by Genetic Analysis and a Patient-Derived Xenograft Study

Therapy for rhabdomyosarcoma (RMS) has generally been limited to combinations of conventional cytotoxic agents similar to regimens originally developed in the late 1960s. Recently, identification of molecular alterations through next-generation sequencing of individual tumor specimens has facilitated the use of more targeted therapeutic approaches for various malignancies. Such targeted therapies have revolutionized treatment for some cancer types. However, malignancies common in children, thus far, have been less amenable to such targeted therapies. This report describes the clinical course of an 8-year-old female with embryonal RMS having anaplastic features. This patient experienced multiple relapses after receiving various established and experimental therapies. Genomic testing of this RMS subtype revealed mutations in BCOR, ARID1A, and SETD2 genes, each of which contributes to epigenetic regulation and interacts with or modifies the activity of histone deacetylases (HDAC). Based on these findings, the patient was treated with the HDAC inhibitor vorinostat as a single agent. The tumor responded transiently followed by subsequent disease progression. We also examined the efficacy of vorinostat in a patient-derived xenograft (PDX) model developed using tumor tissue obtained from the patient’s most recent tumor resection. The antitumor activity of vorinostat observed with the PDX model reflected clinical observations in that obvious areas of tumor necrosis were evident following exposure to vorinostat. Histologic sections of tumors harvested from PDX tumor-bearing mice treated with vorinostat demonstrated induction of necrosis by this agent. We propose that the evaluation of clinical efficacy in this type of preclinical model merits further evaluation to determine if PDX models predict tumor sensitivity to specific agents and/or combination therapies.

Regulation of alveolar septation by microRNA-489

MicroRNAs (miRs) are small conserved RNA that regulate gene expression. Bioinformatic analysis of miRNA profiles during mouse lung development indicated a role for multiple miRNA, including miRNA-489. miR-489 increased on completion of alveolar septation [postnatal day 42 (P42)], associated with decreases in its conserved target genes insulin-like growth factor-1 (Igf1) and tenascin C (Tnc). We hypothesized that dysregulation of miR-489 and its target genes Igf1 and Tnc contribute to hyperoxia-induced abnormal lung development. C57BL/6 mice were exposed to normoxia (21%) or hyperoxia (85% O2) from P4 to P14, in combination with intranasal locked nucleic acid against miR-489 to inhibit miR-489, cytomegalovirus promoter (pCMV)-miR-489 to overexpress miR-489, or empty vector. Hyperoxia reduced miR-489 and increased Igf1 and Tnc. Locked nucleic acid against miR-489 improved lung development during hyperoxia and did not alter it during normoxia, whereas miR-489 overexpression inhibited lung development during normoxia. The 3' untranslated region in vitro reporter studies confirmed Igf1 and Tnc as targets of miR-489. While miR-489 was of epithelial origin and present in exosomes, its targets Igf1 and Tnc were produced by fibroblasts. Infants with bronchopulmonary dysplasia (BPD) had reduced lung miR-489 and increased Igf1 and Tnc compared with normal preterm or term infants. These results suggest increased miR-489 is an inhibitor of alveolar septation. During hyperoxia or BPD, reduced miR-489 and increased Igf1 and Tnc may be inadequate attempts at compensation. Further inhibition of miR-489 may permit alveolar septation to proceed. The use of specific miRNA antagonists or agonists may be a therapeutic strategy for inhibited alveolarization, such as in BPD.

Surgical and Anesthetic Management of a Mediastinal Fatty Tumor: Lipoblastoma

Lipoblastoma is a rare fatty tumor that is diagnosed almost exclusively in children. Presentation often consists of respiratory symptoms; chest computed tomography shows a hypodense, low, attenuated mediastinal mass. Surgical approach and anesthetic management are dependent on the location of the tumor and the degree of airway compression; in most cases, a thoracotomy is performed, although a sternotomy is used in selected cases. Final diagnosis can be confirmed using molecular genetic analysis; a genetic hallmark of lipoblastoma is the rearrangement of chromosomal region 8q12 and the PLAG1 gene. Tumor recurrence is rare when a complete resection is performed.

Multiple native flavin reductases in camphor-metabolizing Pseudomonas putida NCIMB 10007: functional interaction with two-component diketocamphane monooxygenase isoenzymes

Although they have been studied for nearly 50 years, the source of the FMNH2 needed for effective biooxidation by the 2,5- and 3,6-diketocamphane monooxygenase (DKCMO) isoenzymes induced by the growth of Pseudomonas putida NCIMB 10007 (ATCC 17453) on camphor remains incompletely characterized. Prior studies have focussed exclusively on enzymes present in cells harvested during late-exponential-phase growth despite considerable circumstantial evidence that the flavin reductase (FR) component of these multicomponent monooxygenases is subject to growth-phase-dependent variation. In this study, a number of alternative FMNH2-generating activities, including both conventional FRs and enzymes also able to serve as ferric reductases, were isolated from camphor-grown cells, and the relative level, and hence potential contribution, of these various proteins shown to vary considerably depending on the point of harvest of NCIMB 10007 within exponential-phase growth. While two constitutive monomeric ferric reductases (molecular masses 27.0 and 28.5 kDa) were found to be the major relevant sources of FMNH2 during the initial stages of growth on camphor-based media, a significant subsequent contribution throughout the mid- to late-exponential phases of growth was also made by the camphor-induced homodimeric 37.0 kDa FR Fred, recently reported to serve such a role exclusively. The possible involvement of camphor-induced putidaredoxin reductase (51.0 kDa) as a contributory activity was also investigated and considered. Studies with highly purified preparations of the isofunctional DKCMOs confirmed the potential of the various reductases to function effectively as sources of the requisite FMNH2 to both monooxygenases at different times throughout growth on camphor.

Polyarteritis nodosa in childhood: recognition of early dermatologic signs may prevent morbidity

Systemic polyarteritis nodosa (PAN) is a vasculitis that affects small to medium-size arteries. Onset in childhood is rare and can cause significant morbidity. Often, cutaneous manifestations can provide early clues toward diagnosis. This article describes a case of childhood systemic PAN that presented with fever, a necrotic skin lesion, and oral ulceration. Intestinal perforation complicated this case. Prompt recognition of childhood PAN is important to prevent serious complications.

Successful treatment of preadolescents with small cell carcinoma of the ovary hypercalcemic type

BACKGROUND

Small cell carcinoma of the ovary hypercalcemic type (SCCOHT) is a rare tumor with a peak incidence in young adulthood that historically has carried a poor prognosis.

OBSERVATIONS

We present 2 advanced stage cases of SCCOHT in preadolescents successfully treated with a combination of cisplatin-based chemotherapy and surgical resection. The more recent patient also underwent consolidative high-dose chemotherapy with stem cell rescue and external beam radiotherapy. Her therapy was concluded with a maintenance course of bevacizumab. The patients are now disease-free 7 years and 30 months, respectively, after diagnosis.

CONCLUSIONS

With aggressive multimodal therapy SCCOHT is curable in children.

Myofibroblast differentiation and enhanced TGF-B signaling in cystic fibrosis lung disease

Rationale

TGF-β, a mediator of pulmonary fibrosis, is a genetic modifier of CF respiratory deterioration. The mechanistic relationship between TGF-β signaling and CF lung disease has not been determined.

Objective

To investigate myofibroblast differentiation in CF lung tissue as a novel pathway by which TGF-β signaling may contribute to pulmonary decline, airway remodeling and tissue fibrosis.

Methods

Lung samples from CF and non-CF subjects were analyzed morphometrically for total TGF-β₁, TGF-β signaling (Smad2 phosphorylation), myofibroblast differentiation (α-smooth muscle actin), and collagen deposition (Masson trichrome stain).

Results

TGF-β signaling and fibrosis are markedly increased in CF (p<0.01), and the presence of myofibroblasts is four-fold higher in CF vs. normal lung tissue (p<0.005). In lung tissue with prominent TGF-β signaling, both myofibroblast differentiation and tissue fibrosis are significantly augmented (p<0.005).

Conclusions

These studies establish for the first time that a pathogenic mechanism described previously in pulmonary fibrosis is also prominent in cystic fibrosis lung disease. The presence of TGF-β dependent signaling in areas of prominent myofibroblast proliferation and fibrosis in CF suggests that strategies under development for other pro-fibrotic lung conditions may also be evaluated for use in CF.

Trial of zoledronic acid and interleukin-2 to expand tumoricidal γδ T cells in vivo in patients with refractory neuroblastoma

TPS10073

Background: CD3+ γδ+ T cells comprise 2 to 5% of the circulating T cells. Vγ9Vδ2+ cells are the dominant circulating γδ T cell and recognize non-peptide phosphoantigens and stress-associated NKG2D ligands expressed on malignant cells. Strategies that incorporate the tumoricidal properties of γδ T cells represent a promising means of harnessing the innate immune system to treat malignancies including neuroblastoma (NB). Indeed, γδ T cells from both healthy volunteers and NB patients exert a potent cytotoxic effect on NB cell lines and autologous NB in vitro following expansion and activation in culture. Vγ9Vδ2+ cells can also be induced to proliferate in vivo. By blocking farnesyl pyrophosphate synthase in the mevalonate pathway of isoprenoid synthesis in monocytes, the aminobisphosphonate zoledronic acid (ZOL) promotes the accumulation of isopentenyl pyrophosphate which is sensed by γδ T cells. IL-2 is also required for robust expansion γδ T cells. Methods: The trial is a prospective, non-randomized trial that assesses two dose levels of recombinant IL-2 (aldesleukin) in combination with ZOL. To be eligible for the study patients must be 2 to 21 years of age with refractory neuroblastoma with no known curative therapeutic options. Patients must also have adequate organ function and performance status. ZOL is given intravenously on day 1, and aldesleukin is given subcutaneously on days 1 to 5 and 15 to 19 of every 28 day cycle. The single-institution study is being conducted at the University of Alabama at Birmingham. Correlative studies include evaluating the absolute count, phenotype, activation, and effector/memory progression of γδ T cells by flow cytometry and the biological function of autologous expanded/activated γδ T cells by in vitro cytotoxicity assays employing established human NB cell lines. In order to determine the ability of in vivo expanded/activated γδ T cells to infiltrate NB tissue, bone marrow core biopsies obtained before and after the first course of therapy from patients with bone marrow metastasis are assayed for T cell infiltration by immunohistochemistry. The study has currently enrolled 1 of the planned 6 patients. Clinical trial information: NCT01404702.

Abstract 1411: Pathogenesis and treatment of rhabdomyosarcoma in a susceptible murine model

Rhabdomyosarcoma (RMS) is the most common soft-tissue sarcoma of childhood. While the establishment of standard multi-modal therapy has led to improved survival, new therapeutic approaches are desperately needed to improve outcomes in patients with metastatic and recurrent disease. Our objective was to develop a highly penetrant mouse model of RMS to study the molecular pathways of the disease and to evaluate novel anticancer agents for the treatment of RMS. The hedgehog (Hh) pathway has been demonstrated to be activated in embryonal RMS. Communication between Hh and PI3K/AKT/mTOR pathways provides a rationale for the study of mTOR inhibitors such as rapamycin in RMS therapy. We developed a novel RMS mouse model by breeding Ptch6-7 knockouts onto a tumor susceptible SKH1 genetic background. We employed these animals (n=20/group) to study the effects of mTOR inhibitor, rapamycin, on the growth and progression of RMS tumors. We found that 42% of the Ptch1+/−SKH1 mice receiving no treatment developed RMS. These tumors were confirmed to have embryonal RMS morphology. These animals spontaneously develop RMS with embryonal histology predominantly in the hind limbs. The tumors developed at approximately 20 weeks of age; thereafter they grew very prolifically. Molecular studies demonstrated high expression of both Myogenin and Myf5. The tumors also manifested Hh pathway activation. The RMS bearing animals were divided into two groups with a third group of Ptch+/+ mice acting as a wild-type control group. Group-I animals receiving no treatment served as positive controls. The increase in tumor size in these animals was compared with the tumor growth of animals treated with rapamycin. The treatment resulted in a significant decrease in the rate of tumor growth as compared to the control group (p&lt;0.05). This treatment also reduced the expression of AKT and Hh pathways, which was consistent with the tumor inhibitory response seen on a gross level. Decreases in markers of tumor invasiveness and VEGF expression were also noted. We conclude that the Ptch1+/− Skh1 mouse represents a novel murine model for aggressive embryonal RMS that recapitulates the pathobiology of human disease. Rapamycin effectively inhibits the growth of Ptch1+/− Skh1 RMS tumors providing insight into the mechanism underlying RMS tumorigenesis. mTOR inhibition with possible Hh pathway cross talk inhibition represents a promising target in the treatment of RMS in this murine model.

Citation Format: Samer Zaid-Kaylani, Joseph G. Pressey, David R. Kelly, Mohammad Athar. Pathogenesis and treatment of rhabdomyosarcoma in a susceptible murine model. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 1411. doi:10.1158/1538-7445.AM2013-1411

Crohn's disease with pulmonary manifestations in children: 2 case reports and review of the literature

Crohn's disease (CD) is a chronic granulomatous disease of unknown etiology that affects primarily the gastrointestinal system but can be associated with extraintestinal manifestations. Latent pulmonary involvement in children with CD has been described, but symptomatic pulmonary disease has rarely been reported in children. In this review, we report two pediatric cases, one with pleural effusion at the time of CD diagnosis and the other with bilateral cavitary lesions in a previously diagnosed CD patient. We review the current literature and summarize the diagnosis and management of pulmonary involvement in CD. Awareness of these pulmonary complications of CD in children may lead to more prompt diagnosis, guide appropriate therapy, and decrease morbidity.

Angiodysplasia (vascular malformations) of the colon presenting as an acute abdomen

Angiodysplasia (vascular malformations) of the colon is extremely rare in children, and, as in adults, present with lower gastrointestinal hemorrhage. Here we report an unusual pediatric case of angiodysplasia of the terminal ileum and cecum presenting as an acute abdomen with radiological features suggestive of lymphoma.

Sarcoidosis in a young child with Alagille syndrome: a case report

We report a now 6-year-old African-American male with both Alagille syndrome and pediatric sarcoidosis. With a prior JAG1 mutation positive diagnosis of Alagille syndrome, he presented to the hospital with a subacute, predominantly respiratory febrile condition, eventually diagnosed as sarcoidosis. A liver biopsy revealed paucity of bile ducts and scattered epithelioid granulomas, while a skin biopsy showed granulomatous angiitis, a manifestation of sarcoidosis not yet reported in a pediatric patient. He has subsequently been treated with corticosteroids, mycophenolate mofetil, and infliximab with clinical response. Alagille syndrome and sarcoidosis have not yet been reported in the medical literature in the same patient to the best of our knowledge. We briefly review these two seemingly unrelated conditions and propose a possible common pathogenic mechanism.

Type 1 hyperlipoproteinemia and recurrent acute pancreatitis due to lipoprotein lipase antibody in a young girl with Sjogren's syndrome

CONTEXT

Type 1 hyperlipoproteinemia (T1HLP) in childhood is most often due to genetic deficiency of lipoprotein lipase (LPL) or other related proteins.

OBJECTIVE

The aim was to report a case of marked hypertriglyceridemia and recurrent acute pancreatitis due to the presence of LPL autoantibody in a young girl who was subsequently diagnosed with Sjögren's syndrome.

SUBJECT AND METHODS

A 9-yr-old African-American girl presented with acute pancreatitis and serum triglycerides of 4784 mg/dl. Strict restriction of dietary fat reduced serum triglycerides, but she continued to experience recurrent pancreatitis. Approximately 18 months thereafter, she developed transient pauciarticular arthritis with elevated serum antinuclear antibody (>1:1280). Minor salivary gland biopsy revealed chronic sialadenitis with a dense periductal lymphocytic aggregate suggestive of Sjögren's syndrome. Genomic DNA was analyzed for LPL, GPIHBP1, APOA5, APOC2, and LMF1. Immunoblotting was performed to detect serum LPL autoantibody.

RESULTS

The patient had no disease-causing variants in LPL, GPIHBP1, APOA5, APOC2, or LMF1. Immunoblotting revealed serum LPL antibody. The patient responded to immunosuppressive therapy for Sjögren's syndrome with resolution of hypertriglyceridemia.

CONCLUSIONS

Unexplained T1HLP in childhood could be secondary to LPL deficiency induced by autoantibodies. Therefore, diagnosis of autoimmune T1HLP should be entertained if clinical features are suggestive of an autoimmune process.

Involvement of the brachial plexus and its branches by cystic hygromas

Lymphatic malformations that involve the nervous system are uncommon. The authors review their experience with involvement of the brachial plexus and its branches by cystic hygromas. A retrospective review of the authors' experience with pathology of the pediatric brachial plexus revealed 4 cases involving patients with compression of this structure and its branches due to cystic hygroma. Although such cases are apparently rare, the neurosurgeon should consider malformations of the lymphatic system in the differential diagnosis of masses involving the brachial plexus and its branches.

2D-difference gel electrophoretic proteomic analysis of a cell culture model of alveolar rhabdomyosarcoma

To evaluate the consequences of expression of the protein encoded by PAX3-FOXO1 (P3F) in the pediatric malignancy alveolar rhabdomyosarcoma (A-RMS), we developed and evaluated a genetically defined in vitro model of A-RMS tumorigenesis. The expression of P3F in cooperation with simian virus 40 (SV40) Large-T (LT) antigen in murine C3H10T1/2 fibroblasts led to robust malignant transformation. Using 2-dimensional-difference gel electrophoresis (2D-DIGE), we compared proteomes from lysates from cells that express P3F + LT versus from cells that express LT alone. Analysis of 2D gel spot patterns by DeCyder image analysis software indicated 93 spots that were different in abundance. Peptide mass fingerprint analysis of the 93 spots by matrix assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) analysis identified 37 nonredundant proteins. 2D-DIGE analysis of cell culture media conditioned by cells transduced by P3F + LT versus by LT alone found 29 spots in the P3F + LT cells leading to the identification of 11 nonredundant proteins. A substantial number of proteins with potential roles in tumorigenesis and myogenesis were detected, most of which have not been identified in previous wide-scale expression studies of RMS experimental models or tumors. We validated the 2D gel image analysis findings by Western blot analysis and immunohistochemistry (IHC). Thus, the 2D-DIGE proteomics methodology described here provided an important discovery approach to the study of RMS biology and complements the findings of previous mRNA expression studies.

TGF-β2 suppresses macrophage cytokine production and mucosal inflammatory responses in the developing intestine

BACKGROUND & AIMS

Premature neonates are predisposed to necrotizing enterocolitis (NEC), an idiopathic, inflammatory bowel necrosis. We investigated whether NEC occurs in the preterm intestine due to incomplete noninflammatory differentiation of intestinal macrophages, which increases the risk of a severe mucosal inflammatory response to bacterial products.

METHODS

We compared inflammatory properties of human/murine fetal, neonatal, and adult intestinal macrophages. To investigate gut-specific macrophage differentiation, we next treated monocyte-derived macrophages with conditioned media from explanted human fetal and adult intestinal tissues. Transforming growth factor-β (TGF-β) expression and bioactivity were measured in fetal/adult intestine and in NEC. Finally, we used wild-type and transgenic mice to investigate the effects of deficient TGF-β signaling on NEC-like inflammatory mucosal injury.

RESULTS

Intestinal macrophages in the human preterm intestine (fetus/premature neonate), but not in full-term neonates and adults, expressed inflammatory cytokines. Macrophage cytokine production was suppressed in the developing intestine by TGF-β, particularly the TGF-β(2) isoform. NEC was associated with decreased tissue expression of TGF-β(2) and decreased TGF-β bioactivity. In mice, disruption of TGF-β signaling worsened NEC-like inflammatory mucosal injury, whereas enteral supplementation with recombinant TGF-β(2) was protective.

CONCLUSIONS

Intestinal macrophages progressively acquire a noninflammatory profile during gestational development. TGF-β, particularly the TGF-β(2) isoform, suppresses macrophage inflammatory responses in the developing intestine and protects against inflammatory mucosal injury. Enterally administered TGF-β(2) protected mice from experimental NEC-like injury.

Treatment of primary CNS lymphoma with high-dose methotrexate in immunocompetent pediatric patients

We report two cases of primary CNS lymphoma (PCNSL) treated with high-dose methotrexate. Though standard adult treatment of PCNSL incorporates whole-brain radiotherapy, the literature suggests it may be possible to delay or avoid radiotherapy and the associated increased risk of neurologic sequelae in pediatric patients. Studies in adults indicate methotrexate therapy can be effective against PCNSL and has advantages over the current standard of treatment. Both patients have no evidence of disease 9 and 7 years after treatment, suggesting high-dose methotrexate may lead to disease control in pediatric patients with PCNSL while avoiding the effects of radiotherapy.

Complete response to carboplatin, gemcitabine, and paclitaxel in a patient with advanced metastatic renal medullary carcinoma

Renal medullary carcinoma (RMC) is a rare and aggressive malignancy seen primarily in patients with sickle-cell trait. We report a complete response to carboplatin, paclitaxel, and gemcitabine in a patient with advanced metastatic RMC.

Sirolimus therapy for fibromatosis and multifocal renal cell carcinoma in a child with tuberous sclerosis complex

A male with tuberous sclerosis complex (TSC) developed a chest wall fibromatosis and bilateral multifocal renal cell carcinoma (RCC). The fibromatosis tumor was initially resected during infancy but recurred 5 years later. At that time, bilateral RCC was also detected, leading to the resection of the more extensively affected right kidney. In an attempt to avoid bilateral nephrectomies, the patient was treated with the mTOR inhibitor sirolimus. Within 6 months of therapy, the fibromatosis and remaining RCC tumors responded substantially with minimal adverse effects.

Chorioamnionitis stimulates angiogenesis in saccular stage fetal lungs via CC chemokines

The fetal lung vasculature forms in tandem with developing airways. Whereas saccular airway morphogenesis is arrested in bronchopulmonary dysplasia (BPD), the potential vascular phenotype in BPD at this stage of development is less well-understood. As inflammation increases the risk of BPD and induces arrest of saccular airway morphogenesis, we tested the effects of Escherichia coli LPS on fetal mouse lung vascular development. Injecting LPS into the amniotic fluid of Tie2-lacZ endothelial reporter mice at embryonic day 15 stimulated angiogenesis in the saccular stage fetal lung mesenchyme. LPS also increased the number of endothelial cells in saccular stage fetal mouse lung explants. Inflammation appeared to directly promote vascular development, as LPS stimulated pulmonary microvascular endothelial cell angiogenesis, cell migration, and proliferation in vitro. Whereas LPS did not increase expression of VEGF, angiopoietin-1 (Ang-1), Tie2, fetal liver kinase-1 (Flk-1), fms-like tyrosine kinase-1 (Flt-1), PDGFA, PDGFB, heparin-binding EGF-like growth factor (HB-EGF), or connective tissue growth factor (CTGF), LPS did stimulate the production of the angiogenic CC chemokines macrophage inflammatory protein-1α (MIP-1α) and monocyte chemoattractant protein-1 (MCP-1). Both MIP-1α and MCP-1 increased angiogenesis in fetal mouse lung explants. In addition, inhibitory antibodies against MIP-1α and MCP-1 blocked the effects of LPS on fetal lung vascular development, suggesting these chemokines are downstream mediators of LPS-induced angiogenesis. We speculate that an inflammation-mediated surge in angiogenesis could lead to formation of aberrant alveolar capillaries in the lungs of patients developing BPD.

Surgical challenges associated with the morphology of the spinal accessory nerve in the posterior cervical triangle: functional or structural?

Object

The spinal accessory nerve (SAN) has been reported to have a distinctly coiled appearance in its course through the posterior cervical triangle of the neck. As this is unusual compared with other peripheral nerves including the cranial nerves, the present histological analysis was performed to further elucidate the reason for this anatomy with potential application in nerve injury and repair.

Methods

Ten adult cadavers underwent dissection of the neck. The SAN was harvested proximally and within the posterior cervical triangle. For comparison with other cranial nerves within the neck, the cervical vagus and hypoglossal nerves were also harvested. All nerves underwent histological analysis. Additionally, 2 human fetuses (11 and 20 weeks' gestation) underwent examination of the SAN in the posterior cervical triangle, and 3 randomly selected specimens were submitted for electromicroscopy.

Results

All SANs were found to have a straight gross configuration proximal to the posterior triangle and a coiled appearance within this geometrical area. Histologically, no differences were identified for the SAN in these 2 locations (that is, proximal to and within the posterior cervical triangle). The histology of the SAN both with routine analysis and electron microscopy was similar in both regions and to nerves used as controls (for example, vagus and hypoglossal nerves). Interestingly, both fetal specimens were found to have coiled SANs in the posterior cervical triangle.

Conclusions

Based on this study, it appears that the tortuous course of the SAN in the posterior triangle arises from functional as opposed to structural forces. It is hoped that this analysis will provide some insight into the nature behind the morphology observed in the SAN within the posterior cervical triangle and aid in future investigations regarding its injury. Moreover, such a coiled nature of this nerve may assist the neurosurgeon in identifying it during, for example, neurotization procedures.

Plasma concentrations of inflammatory cytokines rise rapidly during ECMO-related SIRS due to the release of preformed stores in the intestine

Extracorporeal membrane oxygenation (ECMO) is a life-saving support system used in neonates and young children with severe cardiorespiratory failure. Although ECMO has reduced mortality in these critically ill patients, almost all patients treated with ECMO develop a systemic inflammatory response syndrome (SIRS) characterized by a 'cytokine storm', leukocyte activation, and multisystem organ dysfunction. We used a neonatal porcine model of ECMO to investigate whether rising plasma concentrations of inflammatory cytokines during ECMO reflect de novo synthesis of these mediators in inflamed tissues, and therefore, can be used to assess the severity of ECMO-related SIRS. Previously healthy piglets (3-week-old) were subjected to venoarterial ECMO for up to 8 h. SIRS was assessed by histopathological analysis, measurement of neutrophil activation (flow cytometry), plasma cytokine concentrations (enzyme immunoassays), and tissue expression of inflammatory genes (PCR/western blots). Mast cell degranulation was investigated by measurement of plasma tryptase activity. Porcine neonatal ECMO was associated with systemic inflammatory changes similar to those seen in human neonates. Tumor necrosis factor-alpha (TNF-alpha) and interleukin-8 (IL-8) concentrations rose rapidly during the first 2 h of ECMO, faster than the tissue expression of these cytokines. ECMO was associated with increased plasma mast cell tryptase activity, indicating that increased plasma concentrations of inflammatory cytokines during ECMO may result from mast cell degranulation and associated release of preformed cytokines stored in mast cells. TNF-alpha and IL-8 concentrations rose faster in plasma than in the peripheral tissues during ECMO, indicating that rising plasma levels of these cytokines immediately after the initiation of ECMO may not reflect increasing tissue synthesis of these cytokines. Mobilization of preformed cellular stores of inflammatory cytokines such as in mucosal mast cells may have an important pathophysiological role in ECMO-related SIRS.

Visualizing CD4 T-cell migration into inflamed skin and its inhibition by CCR4/CCR10 blockades using in vivo imaging model

BACKGROUND

Chemokines are critical mediators of T-cell homing into inflamed skin. The complex nature of this multicellular response makes it difficult to analyse mechanisms mediating the early responses in vivo.

OBJECTIVES

To visualize directly T-cell homing into inflamed skin and its inhibition by blockades using a unique noninvasive confocal microscopy.

MATERIALS AND METHODS

A mouse model of allergic contact dermatitis was used. T cells from oxazolone-sensitized and -challenged Balb/c mice were first analysed phenotypically in vitro. CD4 T cells were then labelled with a tracker dye and transferred into Balb/c-SCID mice. The recipient mice were challenged with oxazolone and CD4 T-cell homing into inflamed skin was visualized.

RESULTS

T cells with the skin homing receptors CCR4 and CCR10 were increased in the affected skin and draining lymph nodes, and effectively attracted by their specific chemokines CCL17, CCL22 and CCL27 in vitro. Using in vivo imaging, T-cell migration into the inflamed skin was observed at 2 h after application, peaking at 12 h and continuing for 48 h. Simultaneous systemic administration of neutralizing antibodies against CCR4 ligands (CCL17 and CCL22) and CCR10 ligand (CCL27) led to a significant suppression of T-cell migration and skin inflammation.

CONCLUSIONS

Our data indicate that these tissue-selective adhesion molecules and chemokine/receptor pathways act in concert to attract specialized T-cell populations to mediate cutaneous inflammation. The in vivo imaging technique can be applicable to other models of cutaneous diseases to help with better understanding of the pathogenesis and monitoring the therapeutic effects.

Epithelial cells in fetal intestine produce chemerin to recruit macrophages

Macrophages are first seen in the fetal intestine at 11-12 wk and rapidly increase in number during the 12- to 22-wk period of gestation. The development of macrophage populations in the fetal intestine precedes the appearance of lymphocytes and neutrophils and does not require the presence of dietary or microbial antigens. In this study, we investigated the role of chemerin, a recently discovered, relatively selective chemoattractant for macrophages, in the recruitment of macrophage precursors to the fetal intestine. Chemerin mRNA/protein expression was measured in jejunoileal tissue from 10- to 24-wk human fetuses, neonates operated for intestinal obstruction, and adults undergoing bariatric surgery. The expression of chemerin in intestinal epithelial cells (IECs) was confirmed by using cultured primary IECs and IEC-like cell lines in vitro. The regulatory mechanisms involved in chemerin expression were investigated by in silico and immunolocalization techniques. IECs in the fetal, but not mature, intestine express chemerin. Chemerin expression peaked in the fetal intestine at 20-24 wk and then decreased to original low levels by full term. During the 10- to 24-wk period, chemerin accounted for most of the macrophage chemotactic activity of cultured fetal IECs. The maturational changes in chemerin expression correlated with the expression of retinoic acid receptor-beta in the intestine. Chemerin is an important mediator of epithelial-macrophage cross talk in the fetal/premature, but not in the mature, intestine. Understanding the regulation of the gut macrophage pool is an important step in development of novel strategies to boost mucosal immunity in premature infants and other patient populations at risk of microbial translocation.

The existence of hypoglossal root ganglion cells in adult humans: potential clinical implications

INTRODUCTION

Ganglion cells of the hypoglossal nerve (HN) have been confirmed in certain animals but have been thought not to be present in man. To investigate for the presence of these structures in adult humans and if present, to verify their functionality, the present study was performed.

MATERIALS AND METHODS

We harvested adult cadaveric HN and observed for ganglion cells. Histological and immunohistochemical analyses were performed on all specimens.

RESULTS

Ganglion cells were found in 33% of specimens. Using immunohistochemistry, we found that these ganglia were sympathetic in nature. Based on our findings, ganglion cells do exist in the human HN although they are located sporadically and are found inconstantly.

CONCLUSIONS

Such information may be valuable in elucidating other functions of the HN and may aid in the histological diagnosis of this nerve. Additionally, pathology involving HN such as paragangliomas, are supported by our findings of the presence of autonomic ganglion cells in some HN specimens.

Shwachman-Diamond syndrome presenting in a premature infant as pancytopenia

Shwachman-Diamond syndrome is a rare autosomal recessive disorder characterized by bone marrow dysfunction, exocrine pancreatic insufficiency, failure to thrive, and skeletal abnormalities. It is most commonly diagnosed in early childhood after the development of hematologic abnormalities. We report a premature infant born at 33 weeks gestation who was small for gestational age and displayed persistent cytopenias requiring transfusion. Genetic testing confirmed a diagnosis of Shwachman-Diamond syndrome (SDS).

Older age at diagnosis of Hirschsprung disease decreases risk of postoperative enterocolitis, but resection of additional ganglionated bowel does not

PURPOSE

This study was conducted to determine the effect of age at diagnosis and length of ganglionated bowel resected on postoperative Hirschsprung-associated enterocolitis (HAEC).

METHODS

Children who underwent endorectal pull-through (ERPT) between January 1993 and December 2004 were retrospectively reviewed. t Test, analysis of variance, Kaplan-Meier, and Cox's proportional hazards analyses were performed.

RESULTS

Fifty-two children with Hirschsprung disease (median age, 25 days; range, 2 days-16 years) were included. Nineteen (37%) had admissions for HAEC. Proportional hazards regression showed that HAEC admissions decreased by 30% with each doubling of age at diagnosis (P = .03) and increased 9-fold when postoperative stricture was present (P < .01), after controlling for type of ERPT, trisomy 21, transition zone level, and preoperative enterocolitis. Thirty-six children, with age at initial operation less than 6 months, were grouped based on length of ganglionated bowel excised (A [5 cm] and B [>5 cm]). No significant difference in the number of HAEC admissions during initial 2 years post-ERPT was seen between groups A (n = 18) and B (n = 18). The study had a power of 0.8 to detect a difference of 1 admission over 2 years.

CONCLUSIONS

Children diagnosed with Hirschsprung disease at younger ages are at a greater risk for postoperative enterocolitis. Excising a longer margin of ganglionated bowel (>5 cm) does not seem to be beneficial in decreasing HAEC admissions.

Adult T-cell leukemia/lymphoma in an adolescent presenting with skin lesions

Adult T-cell leukemia/lymphoma is a T-cell malignancy caused by the human T-cell lymphotropic virus-I. Adult T-cell leukemia/lymphoma is primarily a disease of adults due to the long latency period between initial infection and development of leukemia. We present a case of acute adult T-cell leukemia/lymphoma in an adolescent. Skin lesions had appeared 3 years earlier and were the initial sign of human T-cell lymphotropic virus-I infection and T-cell malignancy. Her disease failed to respond to both intensive chemotherapy and antiviral therapy. Cutaneous lesions are sometimes the initial sign of adult T-cell leukemia/lymphoma and early recognition is imperative.

Studies of nitrile oxide cycloadditions, and the phenolic oxidative coupling of vanillin aldoxime by Geobacillus sp. DDS012 from Italian rye grass silage

During studies directed towards the discovery of nitrile hydrolysing enzymes from thermophiles, vanillin aldoxime was incubated with the thermophilic organism, Geobacillus sp. DDS012 isolated from Italian rye grass (Lolium multiflorum) silage. The predominant product was a dihydro-dimer, which could only be characterised by LC-MS. This was initially imagined to be the product of cycloaddition of vanillin aldoxime with the corresponding nitrile oxide, but preparation of the supposed adduct and model studies excluded this possibility. The rate constant for the second order dimerisation of 4-O-acetyl vanillin nitrile oxide was measured (1.21 x 10(-4) M(-1) s(-1), 0.413 M, 25 degrees C) and the (13)C-NMR signal for the nitrile oxide carbon was observed (delta(C) 34.4, br. t (1)J(13)C,(14)N circa 50 Hz). Treatment of vanillin aldoxime with potassium persulfate and iron sulfate gave material with the same LC-MS properties as the natural product, which is therefore identified as 5,5'-dehydro-di-(vanillin aldoxime) 1d formed by phenolic oxidative coupling.

Tethering tracts in spina bifida occulta: revisiting an established nomenclature

OBJECT

The goal of the present study goal was to systematically confirm the previously recognized nomenclature for tethering tracts that are part of the spectrum of occult spinal dysraphic lesions.

METHODS

The tethering tract in 20 patients with spina bifida occulta underwent histological examination with H & E staining and epithelial membrane antigen (EMA) immunolabeling, and additional selected specimens were stained with Masson trichrome.

RESULTS

All tethering tracts contained fibrous connective tissue. Four tracts were lined with epithelial cells and either originated within a dermoid cyst, terminated at a skin dimple/sinus opening, or had both of these characteristics. No tethering tracts exhibited EMA positivity or meningeal elements. Although all tethering tracts originated in juxtaposition to the spinal cord, their termination sites were variable.

CONCLUSIONS

Based on histological findings and presumed embryological origin, the authors broadly classified tethering tracts terminating within the dura mater, epidural space, or lamina as "short tethering tracts" (STTs). The STTs occurred mostly in conjunction with split cord malformations and had a purely fibrous composition. Tethering tracts terminating superficial to the overlying lamina were classified as "long tethering tracts" (LTTs), and the authors propose that these are embryologically distinct from STTs. The LTTs were of two varieties: epithelial and nonepithelial, the former being typically associated with a skin dimple or spinal cord (epi)dermoid cyst. In fact, analysis of the data suggested that not every tethering tract terminating in or on the skin should be classified as a dermal sinus tract without histological confirmation, and because no evidence of meningeal tissue-lined tracts was detected, the use of the term "meningocele manqué" may not be appropriate.

Human spinal arachnoid villi revisited: immunohistological study and review of the literature

OBJECT

Few have described the relationship between arachnoid protrusions (villi) and adjacent spinal radicular veins, and the descriptions that do exist are conflicting. Some authors have even denied the presence of spinal arachnoid villi, suggesting that they play no role in cerebrospinal fluid (CSF) absorption.

METHODS

To further elucidate these structures, laminectomies from C-2 inferiorly to S-2 were performed in 10 fresh human adult cadavers. Following removal of the laminae, the dural nerve sleeves were identified and the spinal nerves excised 1 cm lateral and medial to the intervertebral foramina. Samples were submitted for histological and immunohistological analysis.

RESULTS

The authors identified arachnoid villi in all specimens. The length of these structures was approximately 50 to 170 microm. Regionally, these villi were more concentrated in the lumbar region, but they were not present at every vertebral level, with observed skip zones. Occasionally, more than one villus was identified per vertebral level. The majority of villi were intimately related to an adjacent radicular vein. There was a direct relationship between the size of the adjacent radicular vein, and the presence and number of arachnoid villi.

CONCLUSIONS

Findings in the present study have demonstrated that arachnoid villi exist and are morphologically associated with radicular veins. These data support the theory that CSF absorption occurs not only intracranially but also along the spinal axis. Further animal studies are necessary to prove that CSF traverses these villi and is absorbed into the spinal venous system.

A new genetic disorder in mitochondrial fatty acid beta-oxidation: ACAD9 deficiency

The acyl-CoA dehydrogenases are a family of multimeric flavoenzymes that catalyze the alpha,beta -dehydrogenation of acyl-CoA esters in fatty acid beta -oxidation and amino acid catabolism. Genetic defects have been identified in most of the acyl-CoA dehydrogenases in humans. Acyl-CoA dehydrogenase 9 (ACAD9) is a recently identified acyl-CoA dehydrogenase that demonstrates maximum activity with unsaturated long-chain acyl-CoAs. We now report three cases of ACAD9 deficiency. Patient 1 was a 14-year-old, previously healthy boy who died of a Reye-like episode and cerebellar stroke triggered by a mild viral illness and ingestion of aspirin. Patient 2 was a 10-year-old girl who first presented at age 4 mo with recurrent episodes of acute liver dysfunction and hypoglycemia, with otherwise minor illnesses. Patient 3 was a 4.5-year-old girl who died of cardiomyopathy and whose sibling also died of cardiomyopathy at age 21 mo. Mild chronic neurologic dysfunction was reported in all three patients. Defects in ACAD9 mRNA were identified in the first two patients, and all patients manifested marked defects in ACAD9 protein. Despite a significant overlap of substrate specificity, it appears that ACAD9 and very-long-chain acyl-CoA dehydrogenase are unable to compensate for each other in patients with either deficiency. Studies of the tissue distribution and gene regulation of ACAD9 and very-long-chain acyl-CoA dehydrogenase identify the presence of two independently regulated functional pathways for long-chain fat metabolism, indicating that these two enzymes are likely to be involved in different physiological functions.

Acrel’s ganglion

No data exists in the extant literature regarding the distal swelling of the posterior interosseous nerve (Acrel's ganglion). To further elucidate this ganglion, ten adult cadavers (20 sides) underwent dissection and histological examination of this structure. No inflammatory response was noted in these histologically normal peripheral nerve structures. No neuronal cell bodies were identified. Although the etiology of such swellings is unclear, the term "ganglia" should not be applied to these enlargements of the distal posterior interosseous nerve.