Clinically aggressive pediatric spinal ependymoma with novel MYC amplification demonstrates molecular and histopathologic similarity to newly described MYCN-amplified spinal ependymomas.

Primary spinal cord tumors contribute to ≤ 10% of central nervous system tumors in individuals of pediatric or adolescent age. Among intramedullary tumors, spinal ependymomas make up ~ 30% of this rare tumor population. A twelve-year-old male presented with an intradural, extramedullary mass occupying the dorsal spinal canal from C6 through T2. Gross total resection and histopathology revealed a World Health Organization (WHO) grade 2 ependymoma. He recurred eleven months later with extension from C2 through T1-T2. Subtotal resection was achieved followed by focal proton beam irradiation and chemotherapy. Histopathology was consistent with WHO grade 3 ependymoma. Molecular profiling of the primary and recurrent tumors revealed a novel amplification of the MYC (8q24) gene, which was confirmed by fluorescence in situ hybridization studies. Although MYC amplification in spinal ependymoma is exceedingly rare, a newly described classification of spinal ependymoma harboring MYCN (2p24) amplification (SP-MYCN) has been defined by DNA methylation-array based profiling. These individuals typically present with a malignant progression and dismal outcomes, contrary to the universally excellent survival outcomes seen in other spinal ependymomas. DNA methylation array-based classification confidently classified this tumor as SP-MYCN ependymoma. Notably, among the cohort of 52 tumors comprising the SP-MYCN methylation class, none harbor MYC amplification, highlighting the rarity of this genomic amplification in spinal ependymoma. A literature review comparing our individual to reported SP-MYCN tumors (n = 26) revealed similarities in clinical, histopathologic, and molecular features. Thus, we provide evidence from a single case to support the inclusion of MYC amplified spinal ependymoma within the molecular subgroup of SP-MYCN.

5' ALK Amplification in Neuroblastoma: A Case Report.

Neuroblastoma is the most common cancer in infants younger than 12 months of age, occurring with an incidence of 1 in 100,000 children. The clinical outcome of neuroblastoma ranges from spontaneous regression to treatment-resistant progression and/or metastasis, and accounts for 8-10% of childhood cancer deaths. Segmental chromosomal aberrations, as well as MYCN and ALK amplification, are among factors contributing to an unfavorable genomic profile and high-risk disease classification. Here, we describe a 5-year-old male who presented with a large right renal neuroblastoma tumor having lung and liver metastases. Fluorescence in situ hybridization analysis indicated the presence of >20 copies of the 5' region of the ALK gene in 26% of cells examined. Subsequent copy number assessment did not confirm ALK amplification, but revealed a gain of exons 2-5 of ALK, consistent with increased copy number for the 5' region of the ALK gene. Subsequent array analysis showed the presence of other unfavorable prognostic genomic features, including segmental gain of the 17q region and amplification of the long arm of chromosome 12 harboring CDK4 and MDM2, both reported to be poor prognostic indicators in patients with atypical clinical features in neuroblastoma. Taken together, this report illustrates the importance of careful interpretation of aberrant FISH findings and subsequent use of orthogonal methods to clarify the presence of genomic alterations to successfully determine potential treatment targets.

Fetal Origin of Placental Hepatic Nodule.

Intraplacental hepatic nodules are extremely rare and range from incidentally identified microscopic nodules to large mass-forming lesions. We describe the case of an incidentally identified intraparenchymal hepatic nodule in the placenta from a near-term delivery of a male infant at 36 weeks gestation. Lesional cells were positive for HepPar1, focally positive for glypican3, and negative for calretinin and alpha-fetoprotein, supportive of hepatocellular origin. Fluorescence in-situ hybridization and chromosomal microarray both showed a male sex chromosome complement (XY) within the nodule, confirming the fetal origin of this nodule. We provide the first report of the confirmed fetal origin of these rare lesions, lending support to the hypothesis that placental hepatic nodules may represent an embryonal rest or residua of abnormal cell migration.

Partial tetrasomy 11q resulting from an intrachromosomal triplication of a 22 Mb region of chromosome 11.

Intrachromosomal triplications are complex chromosomal rearrangements which arise during meiosis or mitosis and lead to a tetrasomic dose of the affected genomic regions. We describe a female patient harboring an intrachromosomal triplication who presented to the Genetics clinic with dysmorphic features, including telecanthus, flat facial profile, and prognathism, short stature, widely spaced nipples, multiple allergy complaints, loose bowel movements, and mild speech delay. Microarray analysis showed a copy number gain of a 22.37 Mb region of chromosome 11 between bands 11q14.1 and 11q22.1. This region contains 95 genes and seven microRNAs, none of which have been implicated in a disease resulting from increased gene dosage. FISH analysis using a probe targeted to the middle of the segment of the copy number gain yielded a pattern indicative of a tetrasomy via an intrachromosomal triplication, with three signals on the long arm of one homologue of chromosome 11 and the fourth on the other homologue. Subsequent FISH analysis showed that the middle triplicated fragment was positioned in an inverted orientation relative to the outer fragments. To investigate the mechanism by which the intrachromosomal triplication occurred, SNP microarray analysis was performed. These results were consistent with the presence of multiple haplotypes in the tetrasomic region and suggest that the intrachromosomal triplication in our patient arose in one parent during meiosis. © 2017 Wiley Periodicals, Inc.

A case of constitutional trisomy 3 mosaicism in a teenage patient with mild phenotype.

Constitutional mosaicism for trisomy 3 is extremely rare, with only a few postnatally diagnosed cases reported in the literature. We report a case of constitutional trisomy 3 mosaicism in a 16-year-old female, who presented with chronic joint pain, easy bruising, joint hypermobility and dysmorphic features, including long, thin facies, over-folded dysplastic ears, and Pierre-Robin sequence (PRS) with cleft palate. The patient was small at birth, had cleft palate repair, developed chronic joint pain at age 12, and has a history of mild leukopenia and mild thrombocytopenia. Microarray analysis was consistent with a mosaic gain of an entire chromosome 3. FISH analysis of peripheral blood and buccal cells showed the presence of the supernumerary chromosome 3 in a low percentage of cells in both tissues, suggesting that the nondisjunction event occurred prior to the germ cell layer differentiation. Since trisomy 3 has been observed somatically in lymphoma, a Hematology/Oncology consultation was provided for the patient. The oncologist's evaluation for malignancy was unremarkable. A review of findings from other trisomy 3 patients reported in the literature reveals a diverse phenotypic spectrum and does not show a correlation between the proportion of abnormal cells observed in peripheral blood and the patients' clinical features or severity. This case demonstrates that the clinical presentation of an individual with trisomy 3 is highly individualized and the clinical course is difficult to predict.

12q14 microdeletion associated with HMGA2 gene disruption and growth restriction.

The 12q14 microdeletion syndrome is a rare condition that has previously been characterized by pre- and postnatal growth restriction, proportionate short stature, failure to thrive, developmental delay, and osteopoikilosis. Previously reported microdeletions within this region have ranged in size from 1.83 to 10.12 Mb with a proposed 2.61 Mb smallest region of overlap containing the LEMD3, HMGA2, and GRIP1 genes. Here, we report on the identification of a 12q14 microdeletion in a female child presenting with proportionate short stature, failure to thrive, and speech delay. The genomic loss (minimum size 4.17 Mb, maximum size 4.21 Mb) contained 25 RefSeq genes including IRAK3, GRIP1, and the 3' portion of the HMGA2 gene. This is the first partial deletion of HMGA2 associated with the 12q14 microdeletion syndrome. This case further clarifies the association of LEMD3 deletions with the 12q14 microdeletion syndrome and provides additional support for the role of the HMGA2 gene in human growth.