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HEY1-NCOA2 fusion is most described in mesenchymal chondrosarcoma. This is the first case report of a primary renal spindle cell neoplasm of uncertain malignant potential with a HEY1::NCOA2 fusion identified by Fusionplex RNA-sequencing that is histologically distinct from mesenchymal chondrosarcoma. The neoplasm was identified in a 33-year-old woman without significant past medical history who underwent partial nephrectomy for an incidentally discovered renal mass. The histologic features of the mass included spindle cells with variable cellularity and monotonous bland cytology forming vague fascicles and storiform architecture within a myxoedematous and collagenous stroma with areas of calcification. The morphologic and immunophenotypic features were not specific for any entity but were most similar to low-grade fibromyxoid sarcoma. To date, the patient has not had recurrence, and the malignant potential of the neoplasm is uncertain.

Malignant peripheral nerve sheath tumors ( MPNSTs) are aggressive tumors with poor prognosis that do not typically respond well to standard chemotherapy. Recently, point mutations involving BRAF V600E have been demonstrated in a subset of MPNST, offering the possibility of targeted treatment. However, the reported prevalence of these alterations is variable. Mutations involving NRAS, which is also involved in the MAPK/ERK pathway and amenable to targeted inhibitors, have not been well characterized in MPNST. In this study, we validated droplet digital polymerase chain reaction for the detection of BRAF V600E and NRAS Q61 mutations and evaluate the prevalence of BRAF V600E and NRAS Q61 mutations in 79 cases of MPNST, including 45 sporadic, 27 NF-1 associated, and 7 radiation-associated tumors. We detected actionable BRAF or NRAS mutations in 3 of 44 sporadic MPNSTs (6.8%), including 2 BRAF V600 and 1 NRAS Q61 mutations, as well as 1 NRAS Q61 mutation in a tumor that was ultimately considered to represent melanoma. These 3 cases with positive mutations were exclusively in sporadic, high-grade MPNST (FNCLCC grade 3 of 3), with a prevalence of 11.5% in this group (3.8% NRAS Q61 mutations and 7.7% BRAF V600 mutations). None of the tumors associated with NF-1 or prior radiation had detectable mutations in the genes tested. Overall, the prevalence of these alterations offers the possibility of targeted therapy in this aggressive type of sarcoma and suggests the potential benefit of routine clinical testing.

Desmoid fibromatosis (DF) is a locally aggressive soft tissue neoplasm with frequent recurrences. DF is characterized by alterations in the Wnt/β-catenin pathway, with the majority showing sporadic mutations in CTNNB1 , whereas others have germline mutations in APC . Immunohistochemical staining for β-catenin is often difficult to interpret and can be negative in up to 30% of cases. Prior studies have shown that some DFs lacking nuclear expression of β-catenin may carry activating CTNNB1 mutations. Droplet digital polymerase chain reaction (ddPCR) has been used effectively in detecting mutations in formalin-fixed, paraffin-embedded (FFPE) samples of various cancer types. In this study, we assess the diagnostic utility of ddPCR to detect CTNNB1 mutations in DF with β-catenin expression on immunohistochemistry (IHC), as well as in diagnostically challenging cases. Of the 28 DFs with nuclear β-catenin expression by IHC, 24 cases showed a CTNNB1 mutation by ddPCR using primers against the most common point mutations in CTNNB1 . The most frequent mutation was T41A (n=14; 50%), followed by S45F (n=8; 33%) and S45P (n=3;12%). We identified 8 additional (myo)fibroblastic lesions of uncertain classification, which were negative for nuclear β-catenin expression by IHC. We detected CTNNB1 mutations in 3 unknown lesions, including S45F (n=2) and S45P (n=1). ddPCR is a sensitive, rapid and cost-efficient methodology to detect common CTNNB1 mutations in DF, especially in diagnostically challenging cases.

Objectives: Spindle cell neoplasms (SCN) share a single commonality of spindle-shaped cells on histopathology but are diverse in etiology. Expanding our collective knowledge of these neoplasms could further research in targeted therapies. We present a case of pediatric cutaneous SCN with a novel etiology, and the methods used to identify its origination. Case Presentation and Results: A 1.5-year-old child presented with a 7-month history of a rapidly enlarging, erythematous, non-painful scalp mass without ulceration or bleeding. The child underwent ultrasound and magnetic resonance imaging, revealing a 2.9 × 3 × 2 cm vascular mass without intracranial connections. The mass was successfully resected at surgery. Subsequent histopathologic and genetic testing indicated a SCN harboring a previously undescribed gene rearrangement between adenylate kinase 5 (AK5) and anaplastic lymphoma kinase (ALK). The patient received close clinical follow-up and at 6 months post-surgery had no recurrent disease. Conclusions: ALK rearrangements are common amongst many tumor types, but to our knowledge, AK5::ALK rearrangement has never been reported in SCN. Considering the rapid development of targeted clinical therapies, including those targeting ALK activity, this finding could be significant in the treatment of future patients with similar clinicopathologic and genetic presentation.

Recurrent alterations in receptor tyrosine kinase (RTK) and downstream effectors are described in infantile fibrosarcoma (IFS)/cellular congenital mesoblastic nephroma (cCMN) and a subset of spindle cell sarcomas, provisionally designated 'NTRK-rearranged' spindle cell neoplasms. These two groups of tumours demonstrate overlapping morphologies and harbour alterations in NTRK1/2/3, RET, MET, ABL1, ROS1, RAF1 and BRAF, although their relationship is not fully elucidated. We describe herein a cohort of paediatric tumours with clinicopathological features not typical for inflammatory myofibroblastic tumour, but rather with similarities to cCMN/IFS harbouring ALK fusions.Clinicopathological features were assessed and partner agnostic targeted RNA sequencing on clinically validated platforms were performed. Tumours occurred in patients aged from 2 to 10 years (median age 2 years) with a 2:2 male to female ratio and an average size of 8.4 cm. Two tumours arose in soft tissues and two in the kidney. Morphological features included spindle to ovoid cells arranged in long fascicles or haphazardly within a myxoid to collagenised stroma; a subset of cases had either dilated, ectatic vessels or focal perivascular hyalinosis. By immunohistochemistry, all cases tested showed cytoplasmic expression of anaplastic lymphoma kinase (ALK) and one case demonstrated co-expression of CD34 and S100.This series of ALK-rearranged IFS-like tumours expands the spectrum of targetable kinases altered in these tumours and reinforces the potential overlap between IFS/cCMN-like tumours and the provisional entity of 'NTRK-rearranged' spindle cell neoplasms.

Infantile fibrosarcoma (IFS)/cellular congenital mesoblastic nephroma (cCMN) commonly harbors the classic ETV6-NTRK3 translocation. However, there are recent reports of mesenchymal tumors with IFS-like morphology harboring fusions of other receptor tyrosine kinases or downstream effectors, including NTRK1/2/3, MET, RET, and RAF1 fusions as well as one prior series with BRAF fusions. Discovery of these additional molecular drivers contributes to a more integrated diagnostic approach and presents important targets for therapy. Here we report the clinicopathologic and molecular features of 14 BRAF-altered tumors, of which 5 had BRAF point mutations and 10 harbored one or more BRAF fusions. Of the BRAF fusion-positive tumors, one harbored two BRAF fusions (FOXN3-BRAF, TRIP11-BRAF) and another harbored three unique alternative splice variants of EPB41L2-BRAF. Tumors occurred in ten males and four females, aged from birth to 32 years (median 6 months). Twelve were soft tissue based; two were visceral including one located in the kidney (cCMN). All neoplasms demonstrated ovoid to short spindle cells most frequently arranged haphazardly or in intersecting fascicles, often with collagenized stroma and a chronic inflammatory infiltrate. No specific immunophenotype was observed; expression of CD34, S100, and SMA was variable. To date, this is the largest cohort of BRAF-altered spindle cell neoplasms with IFS-like morphology, including not only seven novel BRAF fusion partners but also the first description of oncogenic BRAF point mutations in these tumors.

We describe a case of a myoepithelial carcinoma of the superficial parotid gland in a 46-year-old male harboring a novel CTCF::NCOA2 gene fusion. To our knowledge, this novel gene fusion has not been described previously in myoepithelial carcinoma. A 46-year-old male patient presented with a mass involving the superficial left parotid gland with extension into the external auditory canal (EAC) and erosion of the conchal cartilage. Histologically, the neoplasm was composed of uniform spindled, epithelioid/ovoid cells arranged in cords and nests within hyalinized to myxoid stroma. On immunohistochemistry (IHC), the tumor cells demonstrated patchy and variable staining for low molecular weight cytokeratin (CAM5.2), pan-cytokeratin (OSCAR), and S-100. Overall, the morphological and immunohistochemical attributes supported a locally aggressive tumor of myoepithelial differentiation consistent with myoepithelial carcinoma. Molecular analysis using a custom 115-gene gene panel by targeted RNA sequencing, showed an in-frame CTCF::NCOA2 fusion. In addition to reporting this novel fusion in myoepithelial carcinoma, we also discuss relevant differential diagnosis, and provide a brief review of NCOA2 gene function in both normal and neoplastic contexts.

Translocations involving FN1 have been described in a variety of neoplasms that share the presence of a cartilage matrix and may also contain a variable extent of calcification. Fusions of FN1 to FGFR1 or FGFR2 have been reported in nine soft tissue chondromas, mostly demonstrated indirectly by FISH analysis. Delineation of FN1 fusions with various partner genes will facilitate our understanding of the pathogenesis and diagnostic classification of these neoplasms. In this study, we present molecular, clinical, and pathologic features of 12 cartilaginous soft tissue neoplasms showing a predilection for the TMJ region and the distal extremities. We analyzed for gene fusions with precise breakpoints using targeted RNA-seq with a 115-gene panel. We detected gene fusions in ten cases, including three novel fusions, FN1-MERTK, FN1-NTRK1, and FN1-TEK, each in one case, recurrent FN1-FGFR2 fusion in five cases, FN1-FGFR1 in one case, and FGFR1-PLAG1 in one case. The breakpoints in the 5' partner gene FN1 ranged from exons 11-48, retaining the domains of a signal peptide, FN1, FN2, and/or FN3, while the 3' partner genes retained the transmembrane domain, tyrosine kinase (TK) domains, and/or Ig domain. The tumors are generally characterized by nodular/lobular growth of polygonal to stellate cells within a chondroid matrix, often accompanied by various patterns of calcification, resembling those described for the chondroblastoma-like variant of soft tissue chondroma. Additional histologic findings include extensive calcium pyrophosphate dihydrate deposition in two cases and features resembling tenosynovial giant cell tumor (TGCT). Overall, while the tumors from our series show significant morphologic overlap with chondroblastoma-like soft tissue chondroma, we describe findings that expand the morphologic spectrum of these neoplasms and therefore refer to them as "calcified chondroid mesenchymal neoplasms." These neoplasms represent a spectrum of chondroid/cartilage matrix-forming tumors harboring FN1-receptor TK fusions that include those classified as soft tissue chondroma as well as chondroid TGCT.

In this study, we present two extra-renal pediatric spindle cell neoplasms with epidermal growth factor receptor (EGFR) internal tandem duplications (ITD). Histologically, these tumors demonstrated the same histologic features seen in other tyrosine kinase-altered spindle cell neoplasms, with one case showing abundant adipose tissue with cellular fibrous septae resembling lipofibromatosis and the other case showing fascicles of spindled cells resembling infantile fibrosarcoma. There was variable expression of CD34, S100, and SMA, and all cases were negative for panTRK. This case series adds to our molecular understanding of the spectrum of tyrosine kinase-altered spindle cell neoplasms and represents the first reported examples of EGFR ITDs in extra-renal tumors. The presence of EGFR alterations in the absence of gene fusions represents a potential therapeutic target and necessitates a broader testing panel for this group of tumors.

The knowledge of clinical features and, particularly, histopathological spectrum of EWSR1-PATZ1-rearranged spindle and round cell sarcomas (EPS) remains limited. For this reason, we report the largest clinicopathological study of EPS to date. Nine cases were collected, consisting of four males and five females ranging in age from 10 to 81 years (average: 49 years). Five tumors occurred in abdominal wall soft tissues, three in the thorax, and one in the back of the neck. Tumor sizes ranged from 2.5 to 18 cm (average 6.6 cm). Five patients had follow-up with an average of 38 months (range: 18-60 months). Two patients had no recurrence or metastasis 19 months after diagnosis. Four patients developed multifocal pleural or pulmonary metastasis and were treated variably by surgery, radiotherapy, and chemotherapy. The latter seemed to have little to no clinical benefit. One of the four patients was free of disease 60 months after diagnosis, two patients were alive with disease at 18 and 60 months, respectively. Morphologically, low, intermediate, and high-grade sarcomas composed of a variable mixture of spindled, ovoid, epithelioid, and round cells were seen. The architectural and stromal features also varied, resulting in a broad morphologic spectrum. Immunohistochemically, the following markers were most consistently expressed: S100-protein (7/9 cases), GFAP (7/8), MyoD1 (8/9), Pax-7 (4/5), desmin (7/9), and AE1/3 (4/9). By next-generation sequencing, all cases revealed EWSR1-PATZ1 gene fusion. In addition, 3/6 cases tested harbored CDKN2A deletion, while CDKN2B deletion and TP53 mutation were detected in one case each. Our findings confirm that EPS is a clinicopathologic entity, albeit with a broad morphologic spectrum. The uneventful outcome in some of our cases indicates that a subset of EPS might follow a more indolent clinical course than previously appreciated. Additional studies are needed to validate whether any morphological and/or molecular attributes have a prognostic impact.

Fibroma of tendon sheath (FTS) is an uncommon benign fibroblastic/myofibroblastic neoplasm that typically arises in the tenosynovial tissue of the distal extremities. Histologically, it is a well-circumscribed proliferation of spindle cells within collagenous stroma with peripheral slit-like vessels. Most examples are relatively hypocellular and more densely collagenous than nodular fasciitis; however, a cellular variant has been described, which has considerable morphologic overlap with nodular fasciitis and has been shown to harbor USP6 translocations in a subset of cases. The incidence of these rearrangements and the identity of the USP6 fusion partners have not been described in detail. In this study we evaluate 13 cases of cellular fibroma of tendon sheath by anchored multiplex PCR/next generation sequencing in order to detect potential gene fusions. Nucleic acids of adequate quality were obtained in 11 cases, demonstrating gene fusions in 7/11 (64%), all of which involve USP6 with a variety of partners, including PKM, RCC1, ASPN, COL1A1, COL3A1, and MYH9. Some unusual histomorphologic findings were present in a subset of cases including palisading growth pattern, epithelioid cells, and osteoclast-like multinucleated giant cells, particularly in the tumors with PKM and ASPN gene partners. Overall, the findings support a biologic relationship between cellular fibroma of tendon sheath and other lesions within the spectrum of USP6-rearranged neoplasms, particularly nodular fasciitis.

Solitary fibrous tumors are mesenchymal fibroblastic tumors that were originally described as intrathoracic lesions but have since been found to occur in many other locations. They may rarely occur as paratesticular masses. Here we present a peculiar case of a solitary fibrous tumor arising in the paratesticular region and exhibiting leiomyoma-like morphology. Confirmation of the tumor as a solitary fibrous tumor was achieved by RNA sequencing showing NAB2::STAT6 fusion. Possible explanations for the unusual tumor morphology include entrapment of normal smooth muscle elements and tumor differentiation into smooth muscle type cells.

Aims The classification of paediatric spindle mesenchymal tumours is evolving, and the spectrum of so-called 'infantile fibrosarcoma' has expanded to include tumours with NTRK, BRAF and MET gene fusions. RET-rearranged paediatric spindle cell neoplasms are an emerging group; there is sparse literature on their clinical, pathological and genetic features, and their nosological place in the canon of soft tissue tumours is uncertain. In this study, we report five RET-rearranged paediatric spindle cell tumours with fusion partners MYH10, KIAA1217 and CLIP2. Methods and results The tumours occurred in the pelvic region, paraspinal region, kidney and subcutaneous tissue of hand and abdomen. The patients' ages ranged from 6 months to 13 years (median 1 year). The tumours were composed of monomorphic spindle cells arranged in a fascicular pattern. Lesional cells had minimally atypical ovoid or tapered nuclei and pale cytoplasm with indistinct borders. Necrosis was not identified. Mitoses numbered three to 12 per 10 high-power field. Cases showed inconsistent and variable expression of S100, CD34 and SMA. Clinical behaviour ranged from small lesions potentially cured by simple resection to large lesions exhibiting metastasis, but responsive to kinase inhibitor therapy. Conclusions Our findings help to define RET-rearranged spindle cell tumours. Although it is likely that these tumours comprise part of the morphological and clinical spectrum of infantile fibrosarcoma (IFS), identification of RET gene alteration is important for its unique therapeutic implications.

The classification of endometrial stromal sarcoma (ESS) has been refined and aided by the discovery of various recurrent gene translocations. Low-grade ESS (LG-ESS) is most commonly characterized by JAZF1-SUZ12 fusions followed by rearrangements involving PHD finger protein-1 (PHF1) and multiple fusion partners, including JAZF1, EPC1, EPC2, and MEAF6. In the present study, integrating anchored polymerase chain reaction and paired-end next-generation ribonucleic acid sequencing, we identified the presence of a novel malignant brain tumor domain-containing 1 (MBTD1)-PHF1 gene fusion in a case of LG-ESS. MBTD1 belongs to the Polycomb gene group, and its fusion with PHF1 is predicted to mediate tumorigenesis through aberrant transcriptional repression. Histology and immunohistochemical studies demonstrated conventional morphology for LG-ESS and clinical follow-up showed no progression of disease after 6 months. These findings help expand the current knowledge on the spectrum of gene rearrangements in the diagnosis of ESS.

OBJECTIVES/HYPOTHESIS The diffuse sclerosing variant of papillary thyroid carcinoma (DSV) may be more aggressive than conventional well-differentiated non-DSV related papillary thyroid carcinomas (N-PTC). STUDY DESIGN Retrospective chart review. METHODS Retrospective review of clinical outcomes for patients 21 years of age or younger who underwent initial surgery for PTC at a single institution from January 1, 2005 to April 1, 2020. Genomic analysis was performed using targeted next-generation sequencing. Data were analyzed using Fischer's exact test and Kaplan-Meier curve log-rank test. RESULTS Our cohort consisted of 72 patients, nine with DSV and 63 with N-PTC. Age at diagnosis was comparable (15.4 vs. 16.2 years, respectively, P = .46). DSV were more likely to be in the high-risk American Thyroid Academy pediatric risk group (100% vs. 41.3%, P = .004), to present with regional cervical lymph node metastases (100% vs. 60.3%, P = .036), and to present with distant metastases (67% vs. 22%, P = .005). No mortality seen in either group over 27.5 (interquartile range 14.8, 46.00) months average follow-up. Throughout the follow-up period, DSV were more likely to experience progression than N-PTC (hazard ratio = 5.7 [95% confidence interval 1.7-20.0; P = .0056]). In a subset of 19 patients with aggressive disease who had molecular testing as part of clinical care we detected RET fusions in nearly all DSV compared to a minority of N-PTC (83% vs. 15.4%, P = .0095). CONCLUSIONS Pediatric patients with DSV have more advanced disease at diagnosis and are more likely to experience progression of disease compared to patients with N-PTC. The prevalence of RET fusions in our cohort recapitulates the frequency of this alteration described in prior studies. LEVEL OF EVIDENCE 4 Laryngoscope, 2021.

Several types of benign and malignant neoplasms harboring GLI1 gene fusions with various partner genes, including ACTB, MALAT1 and PTCH1, have been described. These neoplasms show a spectrum of morphologic features and immunohistochemical profiles. However, the GLI1 gene fusion has not been described in soft tissue myoepithelial neoplasms previously. In this study, we reported a novel TUBA1A-GLI1 gene fusion in soft tissue neoplasm occurring in the chest wall of a 35-year-old male. The neoplasm shows morphologic features and immunophenotype of myoepithelial differentiation. FusionPlex analysis detected TUBA1A-GLI1 fusion in the neoplasm. The fusion transcript is comprised of 3′ end of exon 1 of TUBA1A and 5′ end of exon 6 of GLI1, retaining the FOXP coiled-coil domain and the DNA-binding zinc finger domains of GLI1. Promoter swapping with the TUBA1A (tubulin alpha 1a) gene likely leads to deregulation of GLI1 expression and its downstream targets. Despite the clinical presentation of multifocal disease and regional lymph node metastasis, the neoplasm in our case study appeared to be stable in a 10-month follow-up, suggesting that this neoplasm likely pursues an indolent clinical course. This study expands the morphologic and immunohistochemical spectrum of the neoplasms with GLI1 gene fusions and identifies a novel fusion in soft tissue myoepithelial neoplasms. As the TUBA1A-GLI1 fusion event likely results in activated GLI1 expression, targeting the Hedgehog pathway is a potential therapeutic option for treatment of patients with this neoplasm.

Infantile fibrosarcoma (IFS)/cellular congenital mesoblastic nephroma (cCMN) commonly harbors the classic ETV6-NTRK3 translocation. However, there are recent reports of mesenchymal tumors with IFS-like morphology harboring fusions of other receptor tyrosine kinases or downstream effectors, including NTRK1/2/3, MET, RET, and RAF1 fusions as well as one prior series with BRAF fusions. Discovery of these additional molecular drivers contributes to a more integrated diagnostic approach and presents important targets for therapy. Here we report the clinicopathologic and molecular features of 14 BRAF-altered tumors, of which 5 had BRAF point mutations and 10 harbored one or more BRAF fusions. Of the BRAF fusion-positive tumors, one harbored two BRAF fusions (FOXN3-BRAF, TRIP11-BRAF) and another harbored three unique alternative splice variants of EPB41L2-BRAF. Tumors occurred in ten males and four females, aged from birth to 32 years (median 6 months). Twelve were soft tissue based; two were visceral including one located in the kidney (cCMN). All neoplasms demonstrated ovoid to short spindle cells most frequently arranged haphazardly or in intersecting fascicles, often with collagenized stroma and a chronic inflammatory infiltrate. No specific immunophenotype was observed; expression of CD34, S100, and SMA was variable. To date, this is the largest cohort of BRAF-altered spindle cell neoplasms with IFS-like morphology, including not only seven novel BRAF fusion partners but also the first description of oncogenic BRAF point mutations in these tumors.

Translocations involving FN1 have been described in a variety of neoplasms, which share the presence of cartilage matrix and a variable extent of calcification. Fusions of FN1 to FGFR1 or FGFR2 have been reported in nine soft tissue chondromas, mostly demonstrated indirectly by FISH analysis. Delineation of FN1 fusions with various partner genes will facilitate our understanding of the pathogenesis and diagnostic classification of these neoplasms. In this study, we present molecular, clinical and pathologic features of 9 cartilaginous soft tissue neoplasms showing a predilection for the TMJ region and the extremities. We analyzed for gene fusions with precise breakpoints using targeted RNA-seq with a 115-gene panel, including FN1, FGFR1 and FGFR2. All 9 cases were positive for a gene fusion, including two novel fusions, FN1-MERTK and FN1-TEK, each in one case, recurrent FN1-FGFR2 in 5 cases, FN1-FGFR1 without the Ig3 domain in one case, and FGFR1-PLAG1 in one case. The breakpoints in the 5’ partner gene FN1 ranged from exons 11-48, retaining the domains of signal peptide, FN1, FN2, and/or FN3, while the 3’partner genes retained the trans-membrane domain, tyrosine kinase domains and /or Ig domain. The tumors with FN1-FGFR1, FN1-FGFR2 and FN1-MERTK fusions are generally characterized by nodular/lobular growth of polygonal to stellate cells within a chondroid matrix, often accompanied by various patterns of calcification. These features resemble those as described for the chondroblastoma-like variant of soft tissue chondroma. Additional histologic findings include calcium pyrophosphate dehydrate deposition and features resembling tenosynovial giant cell tumor. Overall, while the tumors from our series show significant morphologic overlap with chondroblastoma-like soft tissue chondroma, we describe novel findings that expand the morphologic spectrum of these neoplasms and have therefore labeled them as “calcified chondroid mesenchymal neoplasms.” These neoplasms represent a distinct pathologic entity given the presence of recurrent FN1-receptor tyrosine kinase fusions.

BackgroundMorphology, clinical behavior, and genomic profiles of renal oncocytoma (RO) and its malignant counterpart chromophobe renal cell carcinoma (ChRCC) are distinctly different. However, there is a substantial group of sporadic oncocytic tumors with peculiar hybrid phenotypes as well as a perplexing degree of morphologic and immunohistochemical overlap between classic RO and ChRCC with eosinophilic cytoplasm. The aim of this study is to provide detailed characterization of these hybrid tumors.DesignThirty eight sporadic oncocytic neoplasms with ambiguous morphology from two institutions were reviewed by 4 pathologists. CKIT positivity was used as a selection criterion. We correlated CK7 and S100A1 immunostaining and detailed morphologic features with cytogenetic profiles. DNA from the FFPE tissues was extracted and analyzed using Cytogenomic Microarray Analysis (CMA) to evaluate copy number alterations and ploidy.ResultsCMA categorized cases into 3 groups: RO (N=21), RO variant (N=7) and ChRCC (N=10). Cytogenetic RO had either no CNA (48%) or loss of chromosome 1p, X or Y (52%). RO-variant had additional chromosomal losses [-9q, –14 (n=2), –13] and chromosomal gains [+1q (n=2), +4, +7 (n=2), +13, +19, +20, and +22]. ChRCC were either hypodiploid with numerous monosomies (40%) or hypotetraploid with multiple relative losses (60%). RO, RO-variant and ChRCC groups differed significantly in tumor architecture (p5% cells (pConclusionsGenomic profile allows classification of oncocytic tumors with ambiguous morphology into RO, RO-variant and ChRCC. Several architectural and cytologic features combined with CK7 expression are significantly associated with cytogenetic RO, RO-variant or ChRCC tumors. Doubled hypodiploidy by whole genome endoduplication is a common phenomenon in eosinophilic ChRCC.Parts of this study were presented in an abstract form at the 104th annual meeting of the United Stated and Canadian Academy of Pathology, Boston, March 21–27, 2015

Background Hypergonadotropic hypogonadism (HH) is characterized by low sex steroid levels and secondarily elevated gonadotropin levels with either congenital or acquired etiology. Genetic factors leading to HH have yet to be fully elucidated. Methods Here, we report on genome and transcriptome data analyses from a male patient with HH and history of growth delay who has an inherited deletion of chromosome Xq28. Expression analyses were done for this patient and his unaffected family members and compared to normal controls to identify dysregulated genes due to this deletion. Results Our patient’s Xq28 deletion is 44,806 bp and contains only two genes, FUNDC2 and CMC4. Expression of both FUNDC2 and CMC4 are completely abolished in the patient. Gene ontology analyses of differentially expressed genes (DEGs) in the patient in comparison to controls show that significantly up-regulated genes in the patient are enriched in Sertoli cell barrier (SCB) regulation, apoptosis, inflammatory response, and gonadotropin-releasing regulation. Indeed, our patient has an elevated follicle stimulating hormone (FSH) level, which regulates Sertoli cell proliferation and spermatogenesis. In his mother and sister, who are heterozygous for this deletion, X-chromosome inactivation (XCI) is skewed toward the deleted X, suggesting a mechanism to avoid FSH dysregulation. Conclusion Compared to the previously reported men with variable sized Xq28 deletions, our study suggests that loss of function of FUNDC2 and CMC4 results in dysregulation of apoptosis, inflammation, and FSH, and is sufficient to cause Xq28-associated HH.

Fibroma of tendon sheath (FTS) is an uncommon benign fibroblastic/myofibroblastic neoplasm that typically arises in the tenosynovial tissue of the distal extremities. Histologically, it is a well-circumscribed proliferation of spindle cells within collagenous stroma with peripheral slit-like vessels. Most examples are relatively hypocellular and more densely collagenous than nodular fasciitis; however, a cellular variant has been described, which has considerable morphologic overlap with nodular fasciitis and has been shown to harbor USP6 translocations in a subset of cases. The incidence of these rearrangements and the identity of the USP6 fusion partners have not been described in detail. In this study we evaluate 13 cases of cellular fibroma of tendon sheath by anchored multiplex PCR/next generation sequencing in order to detect potential gene fusions. Nucleic acids of adequate quality were obtained in 11 cases, demonstrating gene fusions in 7/11 (64%), all of which involve USP6 with a variety of partners, including PKM, RCC1, ASPN, COL1A1, COL3A1, and MYH9. Some unusual histomorphologic findings were present in a subset of cases including palisading growth pattern, epithelioid cells, and osteoclast-like multinucleated giant cells, particularly in the tumors with PKM and ASPN gene partners. Overall, the findings support a biologic relationship between cellular fibroma of tendon sheath and other lesions within the spectrum of USP6-rearranged neoplasms, particularly nodular fasciitis.

IntroductionHypoplastic left heart syndrome (HLHS) is a rare but devastating congenital heart defect (CHD) accounting for 25% of all infant deaths due to a CHD. The etiology of HLHS remains elusive, but there is increasing evidence to support a genetic cause for HLHS; in particular, this syndrome is associated with abnormalities in genes involved in cardiac development. Consistent with the involvement of heritable genes in structural heart abnormalities, family members of HLHS patients have a higher incidence of both left- and right-sided valve abnormalities, including bicuspid aortic valve (BAV).Case presentationWe previously described (Am J Med Genet A 173:1848–1857, 2017) a 4-generation family with a 6q25.1 microdeletion encompassingTAB2, a gene known to play an important role in outflow tract and cardiac valve formation during embryonic development. Affected adult family members have short stature, dysmorphic facial features, and multiple valve dysplasia, including BAV. This follow-up report includes previously unpublished details of the cardiac phenotype of affected family members. It also describes a baby recently born into this family who was diagnosed prenatally with short long bones, intrauterine growth restriction (IUGR), and HLHS. He was the second family member to have HLHS; the first died several decades ago. Postnatal genetic testing confirmed the baby had inherited the familialTAB2deletion.ConclusionsOur findings suggestTAB2haploinsufficiency is a risk factor for HLHS and expands the phenotypic spectrum of this microdeletion syndrome. Chromosomal single nucleotide polymorphism (SNP) microarray analysis and molecular testing for aTAB2loss of function variant should be considered for individuals with HLHS, particularly in those with additional non-cardiac findings such as IUGR, short stature, and/or dysmorphic facial features.

ALK rearranged renal cell carcinoma (ALK-RCC) has recently been included in 2016 WHO classification as a provisional entity. In this study, we describe 12 ALK-RCCs from 8 institutions, with detailed clinical, pathological, immunohistochemical (IHC), fluorescence in situ hybridization (FISH), and next generation sequencing (NGS) analyses. Patients' age ranged from 25 to 68 years (mean, 46.3 years). Seven patients were females and five were males (M:F = 1:1.4). Tumor size ranged from 17 to 70 mm (mean 31.5, median 25 mm). The pTNM stage included: pT1a (n = 7), pT1b (n = 1), and pT3a (n = 4). Follow-up was available for 9/12 patients (range: 2 to 153 months ; mean 37.6 months) ; 8 patients were alive without disease and one was alive with distant metastases. The tumors demonstrated heterogeneous, 'difficult to classify' morphology in 10/12 cases, typically showing diverse architectural and cellular morphologies, including papillary, tubular, tubulocystic, solid, sarcomatoid (spindle cell), rhabdoid, signet-ring cell, and intracytoplasmic vacuoles, often set in a mucinous background. Of the remaining two tumors, one showed morphology resembling mucinous tubular and spindle cell renal cell carcinoma (MTSC RCC-like) and one was indistinguishable from metanephric adenoma. One additional case also showed a focal metanephric adenoma-like area, in an otherwise heterogeneous tumor. By IHC, all tumors were diffusely positive for ALK and PAX8. In both cases with metanephric adenoma-like features, WT1 and ALK were coexpressed. ALK rearrangement was identified in 9/11 tumors by FISH. ALK fusion partners were identified by NGS in all 12 cases, including the previously reported: STRN (n = 3), TPM3 (n = 3), EML4 (n = 2), and PLEKHA7 (n = 1), and also three novel fusion partners: CLIP1 (n = 1), KIF5B (n = 1), and KIAA1217 (n = 1). ALK-RCC represents a genetically distinct entity showing a heterogeneous histomorphology, expanded herein to include unreported metanephric adenoma-like and MTSC RCC-like variants. We advocate a routine ALK IHC screening for "unclassifiable RCCs" with heterogeneous features.

Additional file 1: Supplemental Figure 1. Chromosomal microarray analysis (CMA) results of VI.3 with HLHS using Agilent GGXChip + SNP v1.0 4x180K array. The deletion detected in VI.3 was a 1.76 Mb deletion of chromosome 6q24.3-q25.1 ([hg19] chr6:148684028–150,448,233) and inherited from his mother (III.5). X axis: log2 Ratio. Y axis: genomic location. Non-mosaic one-copy deletions have log2R = − 1. UCSC genes in the deleted region.

Pilocytic astrocytoma is a low-grade glial neoplasm of the central nervous system (CNS) that tends to occur in the pediatric population and less commonly presents in adults. Hereditary pilocytic astrocytoma is often associated with germline genetic alterations in the tumor suppressor NF1, the gene responsible for the syndrome neurofibromatosis type 1. Sporadic pilocytic astrocytoma frequently harbors somatic alterations in BRAF, with rare pilocytic astrocytomas containing alterations in FGFR1 and NTRK2. NTRK2 encodes for the protein tropomyosin receptor kinase B (TrkB), which is a neurotrophin receptor with high affinity for Brain-Derived Neurotrophic Factor (BDNF), and plays a role in several physiological functions of neurons, including cell survival and differentiation. In this report, we describe a novel PML-NTRK2 gene fusion occurring in an adult sporadic pilocytic astrocytoma and review the biology and implications of specific NTRK2 mutations occurring in CNS neoplasms.

Renal cell neoplasia are heterogeneous with diverse histology, genetic alterations, and clinical behavior that are diagnosed mostly on morphologic features. The Renal Cell Neoplasia Workgroup of the Cancer Genomics Consortium systematically evaluated peer-reviewed literature on genomic studies of renal cell carcinoma (RCC), including clear cell RCC, papillary RCC, chromophobe RCC, and the translocation RCC involving TFE3, TFEB and MITF rearrangements, as well as benign oncocytoma, which together comprise about 95% of all renal cell neoplasia. The Workgroup curated recurrent copy number alterations (CNAs), copy-neutral loss-of-heterozygosity (cnLOH), rearrangements, and mutations, found in each subtype and assigned clinical relevance according to established criteria. In clear cell RCC, loss of 3p has a disease-initiating role and most likely also in progression with mutations detected in VHL and other genes mapped to this arm, and loss of 9p and/or 14q has well-substantiated prognostic utility. Gain of chromosomes 7 and 17 are hallmark CNAs of papillary RCC, but patterns of other CNAs as detected by chromosomal microarray analysis (CMA) afford sub-classification into Type 1 and 2 with prognostic value, and for further sub-stratification of Type 2. Inherent chromosome loss in chromophobe RCC as detected by CMA is useful for distinguishing the eosinophilic variant from benign oncocytoma which in contrast exhibits few CNAs or rearranged CCND1, but share mitochondrial DNA mutations. In morphologically atypical RCCs, rearrangement of TFE3 and TFEB should be considered in the differential diagnosis, portending an aggressive RCC subtype. Overall, this evidence-based review provides a validated role for assessment of CNAs in renal cell neoplasia in the clinical setting to assist in renal cell neoplasm diagnosis and sub-classification within subtypes that is integral to the management of patients, from small incidentally found renal masses to larger surgically resected specimens, and simultaneously identify the presence of key alterations portending outcome in malignant RCC subtypes.

Objectives To develop and test an integrated approach to human epidermal growth factor receptor 2 (HER2) copy number analysis in breast cancer using in situ hybridization (ISH) and cytogenomic microarray (CMA). Methods CMA was performed on four clinical breast cancer samples with nonclassical patterns of HER2 ISH results. Integrated analysis was performed by correlating the data from pathology review, ISH, and CMA. Results Integrated analysis provided a more comprehensive view of the genomic copy number landscape that informed HER2 copy number analysis, but ISH provided essential data in all cases. Conclusions CMA can be helpful for clarifying HER2 amplification status in breast cancer. However, uncertainties over tumor percentage, clonal heterogeneity, and varying ploidy levels present challenges for genomic methods such as CMA. Accurate interpretation of HER2 copy number by CMA requires correlation with the pathology and ISH data.

BACKGROUND: Novel agents added to front-line treatments for adult ALL yield high rates of measurable residual disease (MRD) negativity and survival. However, these approaches are infeasible outside large centers and in lower-resource settings. HyperCVAD is commonly used regardless of Philadelphia chromosome (Ph) status but has limitations, particularly in older patients (pts). Because of its efficacy for high-grade lymphomas (NEJM 2013, p. 1915), we hypothesized that DA-EPOCH would be active and safe in adult ALL. METHODS: Details of this study have been reported (ASH 2018, #1519; NCT03023046). Adults with newly-diagnosed ALL were eligible if not candidates for pediatric-inspired therapy (ie, Ph+, age ≥ 40). DA-EPOCH was given with G-CSF (Blood 2002, p. 2685). After treatment of the 1 st 5 pts, the dose-adjustment paradigm was employed once cytopenias were not due to ALL, typically after cycle 2. If Ph+, imatinib (IM) 600 mg or dasatinib (DAS) 100 mg daily on Days 1-14 of each cycle was added. If CD20+, rituximab 375 mg/m 2 was given once per cycle regardless of Ph status. Up to 8 cycles could be given followed by maintenance (POMP ± TKI) or allogeneic transplant (HCT). Pts with WBC > 30K/µL or LDH > 3x upper limit of normal at diagnosis received 10 doses of intrathecal methotrexate as CNS prophylaxis, and others received 8. Response was determined by bone marrow aspirate morphology (morph), multiparameter flow cytometry (MFC) and (for Ph+) BCR-ABL RT-PCR, with complete molecular response (CMR) assigned when the latter was undetectable. When MRD- by MFC (MFC-) per EuroFlow criteria (Leukemia 2010, p. 521), high-throughput sequencing-based MRD testing (HTS; ClonoSEQ) was performed. IKZF1plus was identified by chromosomal microarray as defined previously (JCO 2018, p. 1240). The primary endpoint was rate of MFC- remission within 4 cycles of therapy. Based on an institutional historical rate of MFC- after ≤ 4 cycles of 50% with hyperCVAD + TKI for Ph+ ALL (Am J Hematol 2018, p. 546), we defined success if we observed such remissions in ≥ 70%. A Simon 2-stage design with α = 0.09 and 80% power led to a sample size of 28 pts and success if ≥ 18 were MFC- after ≤ 4 cycles. For Ph-, we enrolled in cohorts (up to 25 total pts) if the upper bound of a 90% confidence interval (CI) stayed ≥ 59%, our historical rate with hyperCVAD. Follow-up provided to 7/1/21. RESULTS: 53/54 enrolled pts were evaluable. Baseline characteristics are in Table 1 and response rates in Table 2. For Ph+ ALL, 20 of 28 pts (71%; 90% CI = 54-85%) reached MFC- after ≤ 4 cycles; TKI used was DAS for 23 pts and IM for 5 pts. In Ph- ALL, 16 of 25 pts (64%; 90% CI = 46-80%) were MFC- after ≤ 4 cycles. Median follow-up of survivors was 22 months (mo; range: 4-50 mo). Median and 2-yr EFS were 15 mo and 32% (respectively); median OS was not reached, and 2-yr OS was 70% (Figure). In those age > 60 yrs, 2-yr EFS was 49% and OS was 71%. In univariate Cox models, neither WBC, age, adverse-risk cytogenetics, IKZF1plus, nor MFC- after ≤ 4 cycles were significantly associated with EFS or OS; the strongest was high-risk WBC with EFS (hazard ratio 2.1, p = 0.068). In sum, 36 pts reached MFC-: relapse occurred in 12 of 23 pts (52%) given maintenance therapy vs 4 of 12 pts (33%) who received HCT (p = 0.48 by Fisher exact test). Of 18 pts without MRD by HTS, 9 (50%) relapsed. None of the 6 pts given blinatumomab for MRD after DA-EPOCH have relapsed. Four pts (8%) had isolated CNS relapse. 44 pts (83%) developed ≥ 1 Grade (Gr) 3+ non-hematologic (heme) AE related to DA-EPOCH, with a mean of 2 per pt. Those seen in ≥ 10% of pts were febrile neutropenia/infection (23 Gr 3, 2 Gr 4); mucositis (7 Gr 3); and ALT increase (6 Gr 3). There was only 1 treatment-related death (2%; gastric hemorrhage). Twelve pts (23%) discontinued due to acute or cumulative toxicity. As for heme AEs in pts treated after cycle 1 (ie, when ALL was not the cause), only 15 pts (34%) had a Gr 4 platelet count at any time. CONCLUSIONS: DA-EPOCH yields comparable response and survival rates (with manageable toxicity) as more logistically-complex therapies in primarily high-risk ALL. When TKI was added for Ph+ disease, rates of MFC- exceeded the predefined threshold for success. Its efficacy and safety profile make it an appealing backbone to which novel agents may be added. Pending results of ongoing multivariable analyses comparing DA-EPOCH to historical treatments, DA-EPOCH could be considered a standard option, particularly in older adults and/or lower-resource settings. Figure 1 Figure 1. Disclosures Cassaday: Pfizer: Consultancy, Research Funding; Kite/Gilead: Consultancy, Honoraria, Research Funding; Amgen: Consultancy, Research Funding; Pepromene Bio: Membership on an entity's Board of Directors or advisory committees; Servier: Research Funding; Merck: Research Funding; Vanda Pharmaceuticals: Research Funding. Percival: Abbvie: Research Funding; Nohla Therapeutics: Research Funding; Cardiff Oncology: Research Funding; Glycomimetics: Research Funding; Biosight: Research Funding; BMS/Celgene: Research Funding; Pfizer: Research Funding; Oscotec: Research Funding; Trillium: Research Funding. Halpern: Gilead: Research Funding; Abbvie: Consultancy; Agios Pharmaceuticals: Research Funding; Tolero Pharmaceuticals: Research Funding; Novartis: Research Funding; Bayer: Research Funding; Imago Pharmaceuticals: Research Funding; Jazz Pharmaceuticals: Research Funding; Agios: Consultancy; Nohla Therapeutics: Research Funding; Pfizer: Research Funding. Becker: Glycomimetics: Research Funding; CVS Caremark: Consultancy; Abbie: Research Funding; BMS: Research Funding; Pfizer: Research Funding; Cardiff Oncology: Research Funding; SecuraBio: Research Funding. Oehler: BMS: Consultancy; OncLive: Honoraria; Takeda: Consultancy; Pfizer: Research Funding. Shustov: Seagen Inc.: Research Funding. Orozco: Actinium Pharmaceuticals, Inc.: Other: site PI for clinical trial(s) sponsored by Actinium, Research Funding. Walter: BMS: Consultancy; Astellas: Consultancy; Agios: Consultancy; Amphivena: Consultancy, Other: ownership interests; Selvita: Research Funding; Pfizer: Consultancy, Research Funding; Jazz: Research Funding; Macrogenics: Consultancy, Research Funding; Immunogen: Research Funding; Celgene: Consultancy, Research Funding; Genentech: Consultancy; Janssen: Consultancy; Kite: Consultancy; Aptevo: Consultancy, Research Funding; Amgen: Research Funding. Radich: Amgen: Membership on an entity's Board of Directors or advisory committees; Novartis: Membership on an entity's Board of Directors or advisory committees; Genentech: Membership on an entity's Board of Directors or advisory committees; BMS: Membership on an entity's Board of Directors or advisory committees. OffLabel Disclosure: Rituximab is not FDA approved for the treatment of acute lymphoblastic leukemia.

Myeloid/lymphoid neoplasms associated with eosinophilia (MLN-Eo) and tyrosine kinase fusion genes include rearrangements of PDGFRB with over 30 different partner genes, most commonly ETV6-PDGFRB. Rearrangements are evident by cytogenetic analysis and fluorescence in situ hybridization (FISH) break-apart probes. Herein, we describe a novel rearrangement partner for PDGFRB. A 25-year-old man with a medical history significant for gout and hypertension presented to medical care after several days of progressive dyspnea, chest pain, fatigue, epistaxis, and rash. Physical exam revealed palpable cervical, axillary, and inguinal lymphadenopathy and massive splenomegaly. By CT scan the spleen measured 25 cm and diffuse lymphadenopathy was identified in the chest, abdomen and pelvis with the largest lymph node mass measuring 8.9 x 2.5 cm. Transthoracic echocardiogram showed normal heart function and no evidence of myocardial injury. The patient subsequently developed respiratory failure requiring intubation and mechanical ventilation, shock requiring vasopressors, and renal failure requiring renal replacement therapy. Initial laboratory evaluation demonstrated a leukocytosis to 83.3 x 10 9/L with neutrophilic predominance with left shift and eosinophilia (10% of WBCs, absolute eosinophil count of 8.2 x 10 9/L); hemoglobin of 8.3 g/dL and hematocrit of 25%; and thrombocytopenia to 50 x 10 9/L. Ferritin was 660 ng/mL, lactate dehydrogenase 384 U/L, and uric acid 10.4 mg/dL. Secondary causes of eosinophilia including infection, immunodeficiency, atopy, medications, and rheumatologic disease were ruled out. The patient was positive for strongyloides IgG antibodies and received ivermectin. Core biopsy of a lymph node was non-diagnostic and could not repeated safely due to progressive severe thrombocytopenia. Skin biopsy demonstrated a perivascular leukocytoclasis, but no abnormal B or T cell population. Bone marrow aspirate and biopsy revealed a hypercellular marrow (90%) with mild trilineage dysplasia, granulocytic hyperplasia, moderate reticulin fibrosis, and slightly increased mast cells. Blasts were not increased and no hemophagocytic histiocytes were identified. Eosinophils accounted for 6.9% of myeloid cells. Flow cytometry did not reveal an abnormal B or T lymphoid, blast or myeloid population. Peripheral blood flow cytometry did not reveal an abnormal B or T-cell population and T-cell rearrangement studies showed an oligoclonal population. No clonal B cell population was identified. FISH, which identified a rearrangement of PDGFRB in 28% of cells, confirmed the diagnosis. Karyotype analysis revealed an abnormal male karyotype with a paracentric inversion of 5q with breakpoints at 5q32 and 5q35. FusionPlex® Solid Tumor Panel (Clinical Genomics Laboratory, University of Washington SOM) identified a novel fusion between RUFY1 and PDGFRB. RUFY1 is expressed in most tissues and encodes a protein that contains a RUN domain and a FYVE-type zinc finger domain and plays a role in early endosomal trafficking (Figure). We are currently demonstrating the fusion is oncogenic and sensitive to tyrosine kinase inhibition in Ba/F3 cells. The patient's remarkable clinical response, however, supports imatinib sensitivity and is in keeping with other published reports of MLN-Eo with PDGFRB rearrangements. Initial treatment included high dose steroids for 7 days and hydroxyurea briefly. Imatinib 400 mg daily was started, then decreased to 200 mg daily due to gastrointestinal toxicity. Follow-up is limited (8 weeks). However, the patient has recovered clinically. Six weeks after starting imatinib he had renal recovery and has achieved a complete hematologic response except for mild anemia due to resolving acute kidney injury. Splenomegaly and peripheral lymphadenopathy have resolved. PDGFRB FISH has declined to 9%. Inversions of chromosome 5 have very rarely been described in association with eosinophilia, but only one report has specifically identified a rearrangement of PDGFRB. This report described a novel rearrangement involving exons 12 to 23 of PDGFRB at 5q32 and the 5′ (UTR) of G3BP1 at 5q33.1. Notably, this specific rearrangement was undetectable by PDGFRB break-apart FISH. These reports and ours highlight the clinical relevance of NGS in identifying novel rearrangement partners. Furthermore, patient-specific ddPCR assays can be designed for sensitive monitoring. Figure 1 Figure 1. Disclosures Oehler: BMS: Consultancy; OncLive: Honoraria; Pfizer: Research Funding; Takeda: Consultancy; Blueprint Medicines: Consultancy.

The knowledge of clinical features and, particularly, histopathological spectrum of EWSR1-PATZ1-rearranged spindle and round cell sarcomas (EPS) remains limited. For this reason, we report the largest clinicopathological study of EPS to date. Nine cases were collected, consisting of four males and five females ranging in age from 10 to 81 years (average: 49 years). Five tumors occurred in abdominal wall soft tissues, three in the thorax, and one in the back of the neck. Tumor sizes ranged from 2.5 to 18 cm (average 6.6 cm). Five patients had follow-up with an average of 38 months (range: 18–60 months). Two patients had no recurrence or metastasis 19 months after diagnosis. Four patients developed multifocal pleural or pulmonary metastasis and were treated variably by surgery, radiotherapy, and chemotherapy. The latter seemed to have little to no clinical benefit. One of the four patients was free of disease 60 months after diagnosis, two patients were alive with disease at 18 and 60 months, respectively. Morphologically, low, intermediate, and high-grade sarcomas composed of a variable mixture of spindled, ovoid, epithelioid, and round cells were seen. The architectural and stromal features also varied, resulting in a broad morphologic spectrum. Immunohistochemically, the following markers were most consistently expressed: S100-protein (7/9 cases), GFAP (7/8), MyoD1 (8/9), Pax-7 (4/5), desmin (7/9), and AE1/3 (4/9). By next-generation sequencing, all cases revealed EWSR1-PATZ1 gene fusion. In addition, 3/6 cases tested harbored CDKN2A deletion, while CDKN2B deletion and TP53 mutation were detected in one case each. Our findings confirm that EPS is a clinicopathologic entity, albeit with a broad morphologic spectrum. The uneventful outcome in some of our cases indicates that a subset of EPS might follow a more indolent clinical course than previously appreciated. Additional studies are needed to validate whether any morphological and/or molecular attributes have a prognostic impact.

Dedifferentiated liposarcoma (DDLS) is characterized at the molecular level by amplification of genes within 12q13-15 including MDM2 and CDK4 . However, other than FNCLCC grade, prognostic markers are limited. We aim to identify molecular prognostic markers for DDLS to help risk stratify patients. To this end, we studied 49 cases of DDLS in our institutional archives and performed cytogenomic microarray analysis on 47 cases. Gene copy numbers for 12 loci were evaluated and correlated with outcome data retrieved from our institutional electronic medical records. Using cut point analysis and comparison of Kaplan-Meier survival curves by log rank tests, high amplification levels of MDM2 (>38 copies) and CDK4 (>30 copies) correlated with decreased disease free survival (DFS) ( P = . 0168 and 0.0169 respectively) and disease specific survival (DSS) ( P = . 0082 and 0.0140 respectively). Additionally, MDM2 and CDK4 showed evidence of a synergistic effect so that each additional copy of one enhances the effect on prognosis of each additional copy of the other for decreased DFS ( P = . 0227, 0.1% hazard). High amplification of JUN (>16 copies) also correlated with decreased DFS ( P = . 0217), but not DSS. The presence of copy number alteration at 3q29 correlated with decreased DSS ( P = . 0192). The presence of >10 mitoses per 10 high power fields and FNCLCC grade 3 also correlated with decreased DFS ( P = . 0310 and 0.0254 respectively). MDM2 and CDK4 gene amplification levels, along with JUN amplification and copy alterations at 3q29, can be utilized for predicting outcome in patients with DDLS.

Congenital heart defects (CHD) are the most frequent type of congenital anomaly and are often associated with genetic and chromosomal syndromes. Haploinsufficiency of TAB2 (TGF-beta activated kinase 1/MAP3K7 binding protein 2) has been proposed to cause valvular and cardiac outflow tract structural abnormalities. In this study, we describe 13 newly identified individuals with microdeletions of chromosome 6q25.1 that involve TAB2. One of the patients in our study cohort has the smallest deletion yet reported, affecting only TAB2. These were compared to 27 other patients reported in the published literature or DECIPHER to have similar microdeletions, for a total study group of 40 patients. Our study shows that individuals with TAB2 deletions are predisposed to developing a primary cardiomyopathy with reduced systolic function, even in the absence of CHD. Our study cohort also shares a number of non-cardiac phenotypic findings: characteristic dysmorphic facial features, intrauterine growth restriction and/or postnatal proportionate short stature, hypotonia, developmental delay and/or intellectual disability, and connective tissue abnormalities. We conclude that a microdeletion of 6q25.1 that includes TAB2 causes a distinctive, multi-systemic syndrome. The 6q25.1 microdeletion syndrome should be considered in a patient with cardiomyopathy or a CHD, especially valve and/or atrial or ventricular septal abnormalities, and with phenotypic features described in this study. We recommend that patients with a TAB2 deletion be screened longitudinally for systolic heart failure, even if an initial echocardiogram is normal.

A 32-year-old G3P2002 (3 pregnancies, 2 births at full term, 0 preterm, 0 abortions, 2 still living) pregnant woman of Filipino ancestry was referred to a tertiary institution for severe intrauterine growth restriction (IUGR)4 at 20 weeks' gestation. Ultrasound showed fetal size uniformly less than expected, with measurements

The period from the 1990s to the 2010s has witnessed a burgeoning sea change in the practice of surgical neuropathology due to the incorporation of genomic data into the assessment of a range of central nervous system (CNS) neoplasms. This change has since matured into the adoption of genomic information into the definition of several World Health Organization (WHO)-established diagnostic entities. The data needed to accomplish the modern diagnosis of CNS neoplasia includes DNA copy number aberrations that may be assessed through a variety of mechanisms. Through a review of the relevant literature and professional practice guidelines, here we provide a condensed and scored overview of the most critical DNA copy number aberrations to assess for a selection of primary CNS neoplasms.

Background Genomic abnormalities in breast cancer have been described according to diverse conceptual frameworks, including histologic subtypes, clinical molecular subtypes, intrinsic DNA, RNA, and epigenetic profiles, and activated molecular pathways. Methods The Cancer Genomics Consortium (CGC) Breast Cancer Workgroup performed an evidence based literature review to summarize current knowledge of clinically significant genomic alterations in breast cancer using CGC levels of evidence. Targetable or disease-defining alterations were prioritized. Results We summarized genomic alterations in breast cancer within a framework of existing clinical tools for diagnosis, risk stratification, and therapeutic management. Using CGC levels of evidence, we catalog copy number profiles, gene expression profiles, and mutations in clinically significant genes. We also describe emerging molecular markers such as methylation profiling and immunotherapy biomarkers. Conclusion A summary of currently available information on breast cancer genomics will enhance precision medicine by serving as an interpretive resource for clinical laboratory geneticists, providing a foundation for future practice guidelines, and identifying knowledge gaps to address in future research.

Rare individuals with 20p11.2 proximal deletions have been previously reported, with a variable phenotype that includes heterotaxy, biliary atresia, midline brain defects associated with panhypopituitarism, intellectual disability, scoliosis, and seizures. Deletions have ranged in size from 277 kb to 11.96 Mb. We describe a newborn with a de novo 2.7 Mb deletion of 20p11.22p11.21 that partially overlaps previously reported deletions and encompasses FOXA2. Her clinical findings further expand the 20p11.2 deletion phenotype to include severe midline cranial and intracranial defects such as aqueductal stenosis with hydrocephalus, mesencephalosynapsis with diencephalic-mesencephalic junction dysplasia, and pyriform aperture stenosis. We also report one individual with a missense variant in FOXA2 who had abnormal glucose homeostasis, panhypopituitarism, and endodermal organ dysfunction. Together, these findings support the critical role of FOXA2 in panhypopituitarism and midline defects.

SERPINH1 encodes the collagen chaperone HSP47 that binds to arginine-rich sequences in the type I procollagen trimers and provides the final steps in the folding and stabilization of the triple helical domain. Loss of both alleles in mice results in very early embryonic lethality. SERPINH1 mutations have been associated with one of the rarest forms of recessively inherited osteogenesis imperfecta (OI) with a moderate to severe phenotype. We identified a family with non-consanguineous unaffected parents who had two children with moderate short stature, low bone density, and fractures. Both children were compound heterozygotes for two mutations: a frameshift in the last exon that deleted the RER retention signal, and a 5,274 bp deletion 2.37 kb upstream from the transcription start site. The maternally-inherited frameshift allele was expressed at normal levels, but the protein was unstable. The mRNA encoded by the second allele represented about 50% of that from the frameshift-containing allele. The upstream deletion was inherited from the father, and the mRNA encoded by that allele in his cultured dermal fibroblasts was also expressed at a low level, which confirmed that this domain had a regulatory function for SERPINH1. Regulatory mutations are uncommon causes of human genetic disorders, and the ability to measure expression levels in appropriate cells is key to their identification.

Translocation renal cell carcinoma (tRCC) affects younger patients and often presents as advanced disease. Accurate diagnosis is required to guide clinical management. Here we evaluate the RNA-sequencing FusionPlex platform with a 115-gene panel including TFE3 and TFEB for tRCC diagnosis and correlate molecular findings with clinicopathological features. We reviewed 996 consecutive RCC cases from our institution over the preceding 7 years and retrieved 17 cases with histological and immunohistochemical features highly suggestive of either TFE3 (n = 16) or TFEB (n = 1). Moderate to strong labeling for TFE3 was present in 15 cases; two cases with weak TFE3 expression were melan-A or cathepsin-K positive. RNA-sequencing detected gene rearrangements in eight cases: PRCC-TFE3 (3), ASPSCR1-TFE3 (2), LUC7L3-TFE3 (1), SFPQ-TFE3 (1), and a novel SETD1B-TFE3 (1). FISH assays of 11 tumors verified six positive cases concordant with FusionPlex analysis results. Two other cases were confirmed by RT-PCR. FusionPlex was superior to FISH by providing precise breakpoints for tRCC-related genes in a single assay and allowing identification of both known and novel fusion partners, thereby facilitating clinicopathological correlations as fusion partners can influence tumor appearance, immunophenotype, and behavior. Cases with partner genes PRCC and novel partner SETD1B were associated with prominent papillary architecture while cases with partner genes ASPSCR1 and LUC7L3 were associated with a predominantly nested/alveolar pattern. The case with SFPQ-TFE3 fusion was characterized by biphasic morphology mimicking TFEB-like translocation RCC. We recommend FusionPlex analysis of RCC in patients under age 50 or when the histologic appearance suggests tRCC.

Detection of disease-defining gene fusions in sarcoma has led to refining their classification, as well as to discover several new entities. The advent of anchored multiplex PCR/targeted RNA next-generation sequencing (AMP/RNA-seq) has allowed for the development of scalable platforms that can simultaneously examine multiple fusion transcripts without prior knowledge of specific fusion partners.In this study, we assess the utility of a FusionPlex sarcoma panel analysis by AMP/RNA-seq to detect disease-defining gene fusions in 16 cases of undifferentiated round cell sarcoma in which prior diagnostic work-up could not establish a definitive diagnosis. The clinical and pathologic features of these cases were correlated with the molecular findings. Validation of the method using 41 cases with known diagnoses showed analytic sensitivity and specificity of 98% and 100%, respectively. Of the 16 cases of undifferentiated round cell sarcoma, gene fusions were found in 9 (56%). These included three cases with CIC-DUX4 fusion, two cases with BCOR-CCNB3, and four single cases with CIC-NUTM2A, HEY1-NCOA2, EWSR1-NFATC2, and NUT-MGA1 fusions. Overall, despite some degree of morphologic overlap, all fusion-positive cases had distinct morphologic features, which can be helpful for their histologic classification. We also describe the first adult case of MGA-NUTM1 fusion sarcoma, as well as cartilaginous differentiation in a BCOR-CCNB3 fusion sarcoma, which has not been previously reported. Our study demonstrated that FusionPlex sarcoma panel analysis, in the appropriate morphologic context, is a sensitive and precise ancillary method for the detection of disease-defining gene fusions in undifferentiated round cell sarcomas, aiding in their definitive classification.