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.

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.

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.

Intratibial Injection Causes Direct Pulmonary Seeding of Osteosarcoma Cells and Is Not a Spontaneous Model of Metastasis: A Mouse Osteosarcoma Model.

BACKGROUND: Although metastasis is the major cause of mortality in patients with osteosarcoma, little is known about how micrometastases progress to gross metastatic disease. Clinically relevant animal models are necessary to facilitate development of new therapies to target indolent pulmonary metastases. Intratibial injection of human and murine osteosarcoma cell lines have been described as orthotopic models that develop spontaneous pulmonary metastasis over time. However, there is variability in reported injection techniques and metastatic efficiency. QUESTIONS/PURPOSES: We aimed to characterize a widely used murine model of metastatic osteosarcoma, determine whether it is appropriate to study spontaneous pulmonary metastasis by establishing a reliable volume for intratibial injection, determine the incidence of primary tumor and metastatic formation, determine the kinetics of pulmonary metastatic seeding and outgrowth, and the contribution of the primary tumor to subsequent development of metastasis. METHODS: The metastatic mouse osteosarcoma cell line K7M2 was injected into the tibia of mice. The maximum volume that could be injected without leakage was determined using Evan's blue dye (n = 8 mice). Primary tumor formation and metastatic efficiency were determined by measuring the incidence of primary tumor and metastatic formation 4 weeks after intratibial injection (n = 30). The kinetics of metastatic development were determined by performing serial euthanasia at 1, 2, 3, and 4 weeks after injection (n = 24; five to six mice per group). Number of metastatic foci/histologic lung section and metastatic burden/lung section (average surface area of metastatic lesions divided by the total surface area of the lung) was calculated in a blinded fashion. To test the contribution of the primary tumor to subsequent metastases, amputations were performed 30 minutes, 4 hours, or 24 hours after injection (n = 21; five to six mice per group). Mice were euthanized after 4 weeks and metastatic burden calculated as described previously, comparing mice that had undergone amputation with control, nonamputated mice. Differences between groups were calculated using Kruskal-Wallis and one-way analysis of variance. RESULTS: The maximum volume of cell suspension that could be injected without leakage was 10 µL. Intratibial injection of tumor cells led to intramedullary tumor formation in 93% of mice by 4 weeks and resulted in detectable pulmonary metastases in 100% of these mice as early as 1 week post-injection. Metastatic burden increased over time (0.88% ± 0.58, week 1; 6.6% ± 5.3, week 2; 16.1% ± 12.5, week 3; and 40.3% ± 14.83, week 4) with a mean difference from week 1 to week 4 of -39.38 (p < 0.001; 95% confidence interval [CI], -57.39 to -21.37), showing pulmonary metastatic growth over time. In contrast, the mean number of metastatic foci did not increase from week 1 to week 4 (36.4 ± 33.6 versus 49.3 ± 26.3, p = 0.18). Amputation of the injected limb at 30 minutes, 4 hours, and 24 hours after injection did not affect pulmonary metastatic burden at 4 weeks, with amputation as early as 30 minutes post-injection resulting in a metastatic burden equivalent to tumor-bearing controls (48.9% ± 6.1% versus 40.9% ± 15.3%, mean difference 7.96, p = 0.819; 95% CI, -33.9 to 18.0). CONCLUSIONS: There is immediate seeding of the metastatic site after intratibial injection of the K7M2 osteosarcoma cell line, independent of a primary tumor. This is therefore not a model of spontaneous metastasis. CLINICAL RELEVANCE: This model should not be used to study the early components of the metastatic cascade, but rather used as an experimental model of metastasis. Improved understanding of this commonly used model will allow for proper interpretation of existing data and inform the design of future studies exploring the biology of metastasis in osteosarcoma.

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.

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.

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.

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.

Eponyms and the Nazi era: time to remember and time for change.

Eponyms are titles of medical disorders named for individuals who originally described the condition. They also help us remember and identify the disorder. Medicine is replete with them, and changing them or eradicating them, for whatever reason, is not simple. But when there is a moral issue involved - for example, research conducted under overwhelming unethical conditions - we believe it wrong to perpetuate and thus "rew ard" the memory of the individual for whom the disorder is named. The name of a syndrome should thus be discontinued if described by an individual whose research used extreme measures or who was involved in atrocities against humanity. Ethical considerations should be introduced into medical nosology just as they exist in patient care and research. This article details a group of notable eponyms, the names of which are associated with overt crimes of the medical community during the Nazi era, and provides alternative medical nomenclature. In addition, examples are provided of eponyms named after Nazi era victims, eponyms of those who protested such injustices, and eponyms of those who had to flee discrimination and death. These should be remembered and even strengthened, as opposed to those of the perpetrators, which should be obliterated. Since the greatest accolade a physician can earn is praise from his colleagues as expressed in an eponym entrenched in one's name, the medical profession should remove any honor given to physicians involved in crimes to humanity.

A case of bronchial granular cell tumor in a pediatric patient.

Only nine cases of bronchial granular cell tumor have previously been reported in pediatric patients. We present a 15-year-old girl with acute-onset right shoulder pain, discovered to have a granular cell tumor causing bronchial stenosis and a cavitating post-obstructive right upper lobe pneumonia. The patient was treated with lobectomy. Bronchial granular cell tumors are benign neoplasms that typically present with recurrent pneumonia. Imaging may demonstrate an endobronchial lesion or an associated post-obstructive opacity, but diagnosis requires tissue sampling. To our knowledge, this is the tenth case of bronchial granular cell tumor in a pediatric patient to be reported since 1926.

The Macrophage Inhibitor CNI-1493 Blocks Metastasis in a Mouse Model of Ewing Sarcoma through Inhibition of Extravasation.

Metastatic Ewing Sarcoma carries a poor prognosis, and novel therapeutics to prevent and treat metastatic disease are greatly needed. Recent evidence demonstrates that tumor-associated macrophages in Ewing Sarcoma are associated with more advanced disease. While some macrophage phenotypes (M1) exhibit anti-tumor activity, distinct phenotypes (M2) may contribute to malignant progression and metastasis. In this study, we show that M2 macrophages promote Ewing Sarcoma invasion and extravasation, pointing to a potential target of anti-metastatic therapy. CNI-1493 is a selective inhibitor of macrophage function and has shown to be safe in clinical trials as an anti-inflammatory agent. In a xenograft mouse model of metastatic Ewing Sarcoma, CNI-1493 treatment dramatically reduces metastatic tumor burden. Furthermore, metastases in treated animals have a less invasive morphology. We show in vitro that CNI-1493 decreases M2-stimulated Ewing Sarcoma tumor cell invasion and extravasation, offering a functional mechanism through which CNI-1493 attenuates metastasis. These data indicate that CNI-1493 may be a safe and effective adjuvant agent for the prevention and treatment of metastatic Ewing Sarcoma.