Oral sirolimus for the treatment of juvenile xanthogranuloma: Report of two pediatric cases.

Juvenile xanthogranuloma (JXG) with extensive cutaneous or visceral organ involvement is often associated with high morbidity and treatment commonly involves surgical excision, radiotherapy, systemic steroids, or chemotherapy. Sirolimus, a mammalian target of rapamycin (mTOR) inhibitor, is an oral antitumor and immunosuppressive therapy used to treat various neoplastic disorders, including histiocytic disorders. We report two pediatric cases of JXG successfully treated with oral sirolimus monotherapy, and postulate that sirolimus may induce rapid disease resolution and long-term remission for patients with both skin-limited and multisystemic JXG. Our findings warrant further investigation of the relationship between the mTOR pathway and JXG.

Geriatric chronic recurrent multifocal osteomyelitis (CRMO) mimicking multifocal multiple myeloma: a first in an octogenarian.

Chronic recurrent multifocal osteomyelitis (CRMO), an autoinflammatory bone disorder characterized by non-bacterial osteomyelitis causing recurrent multifocal bone lesions, is a well-known, yet uncommon pediatric condition that rarely affects adults; to date, it has never been diagnosed over the age of 75. The following report will discuss the first octogenarian diagnosed with CRMO and therefore represents an exceptionally rare presentation of a rare disease. An 83-year-old woman presented with progressive right shoulder, forearm, and hip pain, with associated weight loss and global weakness, requiring a wheelchair for mobility. Imaging revealed a pathologic right ulna fracture in addition to lytic lesions of the right proximal humerus and proximal femur. The clinical picture was thus that of a patient with probable multiple myeloma versus metastatic disease. After an extensive workup, however, the lesions were not malignant; histologic findings were instead suggestive of chronic osteomyelitis with negative cultures. Given the multifocal nature of this condition, combined with a lack of clinical symptoms of infection, a diagnosis of CRMO was rendered. The patient underwent intramedullary nailing of the right femur and splinting of the ulna, with a subsequent remarkable recovery to painless ambulation, complete union of the right ulna fracture, and resolution of the lytic lesions without receiving any targeted medical treatment. This case highlights the importance of maintaining CRMO on the differential for multifocal skeletal lesions, regardless of age. Performing a thorough workup with necessary imaging, biopsy, and culture are critical to establishing this diagnosis, which can only made as a diagnosis of exclusion.

A Rare Case of Intraosseous Papillary Hemangioma of the Head and Neck.

Papillary hemangioma is a novel variant of intravascular hemangioma. It is more common in adults and has a male predominance. Most tumors reported so far are solitary and cutaneous. Here we present a rare case of an intraosseous papillary hemangioma involving the frontal bone. Brain imaging in a 69-year-old man with a slowly enlarging swelling on the right frontal area following an accidental fall demonstrated a 4.5 cm × 1.7 cm × 4.2 cm mass originating from the right frontal bone, with a tiny defect on the orbital roof. A malignant process was favored, and the mass was removed. Histopathology revealed a vascular lesion showing intraosseous distribution with foci of extension into the fibrous connective tissue. There were areas of plump endothelial cells with intracytoplasmic hyaline globules arranged in papillary configuration. The lesional cells were immunoreactive with CD34. AE1/AE3, EMA, PR, D2-40, inhibin, and S100 stains were negative. Ki-67 was low. This is the first intraosseous and second noncutaneous papillary hemangioma. Clinically it differs from other cases by the presence of trauma as a preceding event. Since its prognosis is unknown such patients should be monitored for recurrence or malignant transformation.

Chromothripsis in lipoblastoma: second reported case with complex PLAG1 rearrangement.

Lipoblastomas (LPBs) are rare benign neoplasms derived from embryonal adipose that occur predominantly in childhood. LPBs typically present with numeric or structural rearrangements of chromosome 8, the majority of which involve the pleomorphic adenoma gene 1 (PLAG1) proto-oncogene on chromosome 8q12. Here, we report on a LPB case on which showed evidence of chromothripsis. This is the second reported case of chromothripsis in LPB.

Locally Invasive Papillary Intralymphatic Angioendothelioma Arising Within a Lymphatic/Venous Malformation.

BACKGROUND Papillary intralymphatic angioendothelioma (PILA) is a rare vascular tumor affecting children and young adults, with less than 50 cases reported in the literature. This tumor typically presents in the extremities, exhibits borderline behavior, and has a prominent lymphatic phenotype. Originally thought to be malignant, PILA was later recognized for its borderline behavior and lymphatic features, leading to its current classification as a "rarely metastasizing lymphatic vascular neoplasm". CASE REPORT We present the case of a 10-year-old girl with a 6-year history of a right facial venous malformation, which was ultimately diagnosed as PILA in the background of lymphatic/venous malformation (LVM). After undergoing surgical excision of a right facial soft-tissue tumor, histopathological examination revealed scattered lymphatics and thin-walled vascular channels with blood in skeletal muscle and fibroadipose tissue. Intraluminal papillary proliferation of vascular spaces lined by cytologically bland spindle cells was observed, along with Kaposiform morphology and small-vessel proliferation. Immunohistochemical staining confirmed endothelial cell markers (D2-40, ERG, CD34, and CD31) and numerous CD3(+) lymphocytes in the lumen, surrounded by CD3(+) T lymphocytes and CD20(+) B lymphocytes in the surrounding stroma. The tumor lacked pleomorphism, significant mitotic activity, and necrosis. CONCLUSIONS PILA presents a diagnostic challenge and should be considered in the differential diagnosis of cutaneous vascular neoplasms. Long-term follow-up is crucial due to its borderline behavior and potential for local invasiveness and metastasis. Accurate diagnosis, aided by characteristic histological and immunohistochemical features, is essential for appropriate management of this rare vascular tumor.

A 53-Year-Old With Progressive Dyspnea.

CASE PRESENTATION: A 53-year-old woman with a history of pulmonary embolism treated with rivaroxaban came to the ED after 4 days of acutely worsening dyspnea and chest pressure. On arrival, her temperature was 36.7 °C; heart rate, 71 beats/min; BP, 98/59 mm Hg; respiratory rate, 22 breaths/min; and Spo2 95% on room air. Her WBC count was elevated at 15,770/µL; hemoglobin, 13.3 g/dL; platelets, 280,000/µL; INR (international normalized ratio), elevated at 1.66; and partial thromboplastin time, elevated at 18.8 s. Serum chemistry results were unremarkable, and pro-brain natriuretic peptide was slightly elevated at 530 pg/mL (normal, < 300 pg/mL).

Solitary Pediatric Osteochondroma of the Spine With Cord Compression.

Osteochondromas typically arise in the appendicular skeleton, with axial lesions occurring less commonly. Osteochondroma of the spine resulting in cord compression and symptomatic myelopathy is relatively rare. Most cases are reported in adolescents and adults. Consequently, there is a scarcity of literature regarding its occurrence in the pediatric population. We report the case of a cervical osteochondroma of C4-6 with cord compression in a nine-year-old girl. Surgical excision with laminectomy and laminotomy successfully resolved all neurologic deficits. A literature review revealed 27 cases of pediatric osteochondromas with cord compression, suggesting that these lesions are not as rare in the pediatric population as previously thought.

The Use of Sunitinib as Maintenance Therapy in a Pediatric Patient With a Poorly Differentiated Thymic Carcinoma.

BACKGROUND: Thymic carcinomas are rare aggressive mediastinal tumors with a median survival of 2 years. OBSERVATION: We present a pediatric patient who was diagnosed with metastatic thymic carcinoma and showed continuous improvement of his primary mass and lung metastases with a regimen of cisplatin/docetaxel followed by long-term maintenance therapy with sunitinib for over 5 years. CONCLUSIONS: This report demonstrates a long-term positive treatment effect using chemotherapy followed by sunitinib in an advanced thymic carcinoma. We are not aware of other reports of pediatric patients with metastatic thymic carcinoma treated with sunitinib maintenance who maintained a durable response for this prolonged period of time.

Features of Intestinal Disease Associated With COVID-Related Multisystem Inflammatory Syndrome in Children.

ABSTRACT: Multisystem inflammatory syndrome in children (MIS-C) is a recently identified syndrome that appears to be temporally associated with novel coronavirus 2019 infection. MIS-C presents with fever and evidence of systemic inflammation, which can manifest as cardiovascular, pulmonary, neurologic, and gastrointestinal (GI) system dysfunction. Presenting GI symptoms are seen in the majority, including abdominal pain, diarrhea, and vomiting. Any segment of the GI tract may be affected; however, inflammation in the ileum and colon predominates. Progressive bowel wall thickening can lead to luminal narrowing and obstruction. Most will have resolution of intestinal inflammation with medical therapies; however, in rare instances, surgical resection may be required.

Histopathologic evaluation of placentas after diagnosis of maternal severe acute respiratory syndrome coronavirus 2 infection.

Background: The impact of maternal severe acute respiratory syndrome coronavirus 2 infection on placental histopathology is not well known. Objective: To determine if any significant placental histopathologic changes occur after the diagnosis of severe acute respiratory syndrome coronavirus 2 infection during pregnancy and whether these changes are correlated with the presence or absence of symptoms associated with the infection. Study Design: A retrospective cohort study of women diagnosed as having severe acute respiratory syndrome coronavirus 2 infection who delivered at a single center from April 9, 2020 to April 27, 2020, and had placental specimens reviewed by the Department of Pathology. Women with singleton gestations and laboratory-confirmed severe acute respiratory syndrome coronavirus 2 infection were eligible for inclusion. Historical controls selected from a cohort of women who delivered 6 months before the study period were matched in a 1:1 fashion by weeks of gestation at delivery. Histopathologic characteristics were evaluated in each placenta, and the incidence of these findings was compared between placentas of those who received a diagnosis of maternal severe acute respiratory syndrome coronavirus 2 infection and historical controls, and between placentas from patients with or without typical symptoms related to the infection. Statistical analyses included the use of Wilcoxon rank-sum test and Fisher's exact test for the comparison of categorical and continuous variables. Statistical significance was defined as a P value of <.05. Results: A total of 50 placentas after the diagnosis of maternal severe acute respiratory syndrome coronavirus 2 infection and 50 historical controls were analyzed. Among the placentas from patients diagnosed with severe acute respiratory syndrome coronavirus 2 infection, 3 (6%) were preterm (33 3/7, 34 6/7, and 36 6/7 weeks of gestation), 16 (32%) were from patients with typical symptoms related to the infection, and 34 (68%) were from patients without typical symptoms related to the infection. All patients had received a diagnosis of severe acute respiratory syndrome coronavirus 2 infection in the third trimester. Decidual vasculopathy was not visualized in any of the placentas from patients diagnosed as having severe acute respiratory syndrome coronavirus 2 infection. There was no statistically significant difference in placental histopathologic characteristics between the groups. Severe acute respiratory syndrome coronavirus 2 test results for all neonates at 24 hours of life were negative. Conclusion: Based on the results of this study, there are no significant placental histopathologic changes that occur after the diagnosis of severe acute respiratory syndrome coronavirus 2 infection in women during the third trimester of pregnancy compared with a gestational age-matched historical control group. Similar incidences of histopathologic findings were also discovered when comparing placentas from patients with severe acute respiratory syndrome coronavirus 2 infection with or without the presence of symptoms typically related to the infection.

A Rare TP53 Mutation Predominant in Ashkenazi Jews Confers Risk of Multiple Cancers.

Germline mutations in TP53 cause a rare high penetrance cancer syndrome, Li-Fraumeni syndrome (LFS). Here, we identified a rare TP53 tetramerization domain missense mutation, c.1000G>C;p.G334R, in a family with multiple late-onset LFS-spectrum cancers. Twenty additional c.1000G>C probands and one c.1000G>A proband were identified, and available tumors showed biallelic somatic inactivation of TP53. The majority of families were of Ashkenazi Jewish descent, and the TP53 c.1000G>C allele was found on a commonly inherited chromosome 17p13.1 haplotype. Transient transfection of the p.G334R allele conferred a mild defect in colony suppression assays. Lymphoblastoid cell lines from the index family in comparison with TP53 normal lines showed that although classical p53 target gene activation was maintained, a subset of p53 target genes (including PCLO, PLTP, PLXNB3, and LCN15) showed defective transactivation when treated with Nutlin-3a. Structural analysis demonstrated thermal instability of the G334R-mutant tetramer, and the G334R-mutant protein showed increased preponderance of mutant conformation. Clinical case review in comparison with classic LFS cohorts demonstrated similar rates of pediatric adrenocortical tumors and other LFS component cancers, but the latter at significantly later ages of onset. Our data show that TP53 c.1000G>C;p.G334R is found predominantly in Ashkenazi Jewish individuals, causes a mild defect in p53 function, and leads to low penetrance LFS. SIGNIFICANCE: TP53 c.1000C>G;p.G334R is a pathogenic, Ashkenazi Jewish-predominant mutation associated with a familial multiple cancer syndrome in which carriers should undergo screening and preventive measures to reduce cancer risk.

Benign infiltrative myofibroblastic neoplasms of childhood with USP6 gene rearrangement.

AIMS: Several morphologically overlapping (myo)fibroblastic neoplasms harbour USP6 fusions, including aneurysmal bone cysts, nodular fasciitis, myositis ossificans, cranial fasciitis, fibro-osseous pseudotumour of the digits, and cellular fibroma of the tendon sheath. USP6-induced neoplasms are almost universally benign and cured by local excision. We aim to highlight the diagnostic value of USP6 fusion detection in a series of aggressive-appearing paediatric myofibroblastic tumours. METHODS AND RESULTS: Three deep-seated, radiographically aggressive, and rapidly growing childhood myofibroblastic neoplasms were morphologically and molecularly characterised by USP6 break-apart fluorescence in-situ hybridisation (FISH), transcriptome sequencing, and targeted capture analysis. Each tumour occurred in the lower-extremity deep soft tissue of a child presenting with pain, limping, or a mass. In all three patients, imaging studies showed a solid mass that infiltrated into surrounding skeletal muscle or involved/eroded underlying bone. The biopsied tumours consisted of variably cellular myofibroblastic proliferations with variable mitotic activity that lacked overt malignant cytological features. FISH showed that all tumours had USP6 rearrangements. On the basis of these results, all three patients were treated with conservative excision with positive margins. The excised tumours had foci resembling nodular fasciitis, fibromatosis, and pseudosarcomatous proliferation. Next-generation sequencing revealed COL1A1-USP6 fusions in two tumours and a COL3A1-USP6 fusion in the third tumour. One tumour had a subclonal somatic APC in-frame deletion. No recurrence was observed during follow-up (8-40 months). CONCLUSION: We present a series of benign, but aggressive-appearing, USP6-rearranged myofibroblastic tumours. These deep-seated tumours had concerning clinical and radiographic presentations and did not fit into one distinct histological category. These cases highlight the diagnostic value of USP6 fusion detection to identify benign nondescript tumours of this group, especially those with aggressive features, to avoid overtreatment.

Gefitinib Inhibits Invasion and Metastasis of Osteosarcoma via Inhibition of Macrophage Receptor Interacting Serine-Threonine Kinase 2.

Most patients with osteosarcoma have subclinical pulmonary micrometastases at diagnosis. Mounting evidence suggests that macrophages facilitate metastasis. As the EGFR has been implicated in carcinoma-macrophage cross-talk, in this study, we asked whether gefitinib, an EGFR inhibitor, reduces osteosarcoma invasion and metastatic outgrowth using the K7M2-Balb/c syngeneic murine model. Macrophages enhanced osteosarcoma invasion in vitro, which was suppressed by gefitinib. Oral gefitinib inhibited tumor extravasation in the lung and reduced the size of metastatic foci, resulting in reduced metastatic burden. Gefitinib also altered pulmonary macrophage phenotype, increasing MHCII and decreasing CD206 expression compared with controls. Surprisingly, these effects are mediated through inhibition of macrophage receptor interacting protein kinase 2 (RIPK2), rather than EGFR. Supporting this, lapatinib, a highly specific EGFR inhibitor that does not inhibit RIPK2, had no effect on macrophage-promoted invasion, and RIPK2-/- macrophages failed to promote invasion. The selective RIPK2 inhibitor WEHI-345 blocked tumor cell invasion in vitro and reduced metastatic burden in vivo In conclusion, our results indicate that gefitinib blocks macrophage-promoted invasion and metastatic extravasation by reprogramming macrophages through inhibition of RIPK2.

Highly Sensitive Blocker Displacement Amplification and Droplet Digital PCR Reveal Low-Level Parental FOXF1 Somatic Mosaicism in Families with Alveolar Capillary Dysplasia with Misalignment of Pulmonary Veins.

Detection of low-level somatic mosaicism [alternate allele fraction (AAF) ≤ 10%] in parents of affected individuals with the apparent de novo pathogenic variants enables more accurate estimate of recurrence risk. To date, only a few systematic analyses of low-level parental somatic mosaicism have been performed. Herein, highly sensitive blocker displacement amplification, droplet digital PCR, quantitative PCR, long-range PCR, and array comparative genomic hybridization were applied in families with alveolar capillary dysplasia with misalignment of pulmonary veins. We screened 18 unrelated families with the FOXF1 variant previously determined to be apparent de novo (n = 14), of unknown parental origin (n = 1), or inherited from a parent suspected to be somatic and/or germline mosaic (n = 3). We identified four (22%) families with FOXF1 parental somatic mosaic single-nucleotide variants (n = 3) and copy number variant deletion (n = 1) detected in parental blood samples and an AAF ranging between 0.03% and 19%. In one family, mosaic allele ratio in tissues originating from three germ layers ranged between <0.03% and 0.65%. Because the ratio of parental somatic mosaicism have significant implications for the recurrence risk, this study further implies the importance of a systematic screening of parental samples for low-level and very-low-level (AAF ≤ 1%) somatic mosaicism using methods that are more sensitive than those routinely applied in diagnostics.

Congenital Hepatoblastoma and Beckwith-Wiedemann Syndrome.

Following the discovery of a fetal hepatic tumor, labor was induced at 38 weeks, and a phenotypically normal female was delivered vaginally. A serum alpha-fetoprotein level at birth was 373,170 ng/mL. Postnatal magnetic resonance imaging confirmed a mass in the right lobe of the liver, and a percutaneous core biopsy revealed an epithelial type hepatoblastoma with predominantly embryonal histology. Methylation testing revealed hypomethylation at imprinting center 2, consistent with a diagnosis of Beckwith-Wiedemann syndrome. This case suggests that Beckwith-Wiedemann syndrome testing should be considered in all patients with hepatoblastoma, even in the absence of other phenotypic stigmata.

USP6 Gene Rearrangement by FISH Analysis in Cranial Fasciitis: A Report of Three Cases.

Cranial fasciitis (CF) is an uncommon benign myofibroblastic proliferation involving the soft and hard tissues of the cranium. It typically occurs in the pediatric population with a male predilection (male-to-female ratio 1.5:1). The clinical presentation is usually a rapidly expanding, painless nodule. Bone erosion may be appreciated radiographically. Histopathologic sections of CF show plump, fibroblast-like cells with pale, oval shaped nuclei and prominent nucleoli in a fibrous or myxoid background. Growth is self-limited and surgical excision is considered curative. Due to these features, CF is thought to be a variant of nodular fasciitis (NF). As with NF, CF may mimic a sarcomatous process and pose a diagnostic challenge to clinicians and pathologists alike. Erickson-Johnson et al. identified rearrangements of the ubiquitin-specific protease 6 (USP6) gene in 44 of 48 cases of NF. MYH9 was the fusion partner in 12 of these cases. To date, the molecular profile of CF has not been studied. Here we present the molecular findings in three cases of CF identified at our institution. Each case was subjected to fluorescence in-situ hybridization with appropriate negative controls. Two of three cases were positive for the USP6 gene rearrangement. The third case failed to hybridize, likely related to nucleic acid damage secondary to decalcification. Negative controls did not demonstrate the genetic rearrangement. These findings warrant further investigation of the USP6 gene rearrangement in CF, as it may prove helpful as a diagnostic adjunct in challenging cases.

The use of 3D printing in shared decision making for a juvenile aggressive ossifying fibroma in a pediatric patient.

Juvenile aggressive ossifying fibromas (JAOF) are rare, typically benign pediatric tumors that are locally aggressive and have high recurrence rates. A 7-year old male presented with a palatal mass and a 3D printed model was created and used as a visual aide to highlight the importance of management in terms of functional, cosmetic, and disease-free outcomes with the family. The patient ultimately underwent successful enucleation with final pathology consistent with JAOF. To our knowledge, this is the first description of the use of 3D printing to help in the shared decision-making process for the treatment of this aggressive tumor.

The Impact of Pathological Criteria on Pediatric Negative Appendectomy Rate.

INTRODUCTION: Negative appendectomy rate (NAR) is a quality metric used in the surgical management of appendicitis. The rates of negative appendectomy (NA) in children range anywhere from 1% to 40% in the literature. Many reports do not provide clear pathological definitions for either appendicitis or NA on which they base their calculation of NAR. We reviewed our experience with pediatric appendectomy and the pathological spectrum encompassed within our definition of a NA and examined how the pathologic definition impacts our hospital's NAR. METHODS: A retrospective review from 2012 to 2016 in a single institution identified 1676 children that underwent appendectomy. Average age was 11.4 (2-18 years). Patient demographics, clinical outcomes and pathological findings were collected. At our institution, appendicitis is defined as the presence of transmural acute inflammation in the appendix and those patients without this finding have been considered to have had a negative appendectomy. RESULTS: 1435 patients underwent appendectomy for presumed appendicitis. The rate of pathologically diagnosed appendicitis was 91.1% (1307/1435) and as such, the NAR was 8.9% (128/1435). Review of the pathology of the NA cohort identified 67/128 (52.3%) patients with completely normal pathology. The remaining 61 patients displayed some sort of pathological abnormality including malignancy (n = 2), fecaliths (n = 9), pinworms (n = 3), granuloma (n = 2), fibrous obliteration (n = 4), isolated periappendiceal inflammation (n = 1), and acute inflammation confined to the mucosa (n = 40). Exclusion of these patients with abnormal pathology decreased the NAR to 4.6%. Patients with pathological abnormalities of the appendix other than transmural inflammation had a higher rate of 30-day readmission than patients with acute appendicitis (8.2% versus 4.5% p < 0.01). CONCLUSION: Pediatric NAR is dependent upon the pathological definition of appendicitis and negative appendectomy. Institutional variation in definition may explain discrepancies in the literature. By example, including only those that show "the absence of inflammation or other appendiceal pathology" would decrease our NAR by 50%. This study calls into question the interpretation of interhospital NAR and the use of NAR as a quality metric in the management of appendicitis. Retrospective comparative study: Level III evidence.