ROS1 Alterations as a Potential Driver of Gliomas in Infant, Pediatric, and Adult Patients.

Gliomas harboring oncogenic ROS1 alterations are uncommon and primarily described in infants. Our goal was to characterize the clinicopathological features and molecular signatures of the full spectrum of ROS1 fusion-positive gliomas across all age groups. Through a retrospective multi-institutional collaboration, we report a collection of unpublished ROS1 fusion gliomas along with the characterization and meta-analysis of new and published cases. A cohort of 32 new and 58 published cases was divided into the following 3 age groups: 19 infants, 40 pediatric patients, and 31 adults with gliomas. Tumors in infants and adults showed uniformly high-grade morphology; however, tumors in pediatric patients exhibited diverse histologic features. The GOPC::ROS1 fusion was prevalent (61/79, 77%) across all age groups, and 10 other partner genes were identified. Adult tumors showed recurrent genomic alterations characteristic of IDH wild-type glioblastoma, including the +7/-10/CDKN2A deletion; amplification of CDK4, MDM2, and PDGFRA genes; and mutations involving TERTp, TP53, PIK3R1, PIK3CA, PTEN, and NF1 genes. Infant tumors showed few genomic alterations, whereas pediatric tumors showed moderate genomic complexity. The outcomes were significantly poorer in adult patients. Although not statistically significant, tumors in infant and pediatric patients with high-grade histology and in hemispheric locations appeared more aggressive than tumors with lower grade histology or those in nonhemispheric locations. In conclusion, this study is the largest to date to characterize the clinicopathological and molecular signatures of ROS1 fusion-positive gliomas from infant, pediatric, and adult patients. We conclude that ROS1 likely acts as a driver in infant and pediatric gliomas and as a driver or codriver in adult gliomas. Integrated comprehensive clinical testing might be helpful in identifying such patients for possible targeted therapy.

Sural nerve biopsy utility by masked assessment of individual histologic preparations.

BACKGROUND AND AIMS: Comprehensive study of sural nerve biopsy utility based on individual histopathologic preparations is lacking. We aimed to quantify the value of different histologic preparations in diagnosis. METHODS: One hundred consecutive sural nerves were studied by standard histological preparations plus graded teased nerve fibers (GTNF), immunohistochemistry, and epoxy-semithin morphometry. Three examiners scored the individual preparations separately by a questionnaire of neuropathic and interstitial abnormalities, masked to the biopsy number, versus a gold-standard of all preparations. Multivariate modeling was utilized to determine best approach versus the gold-standard. RESULTS: Highest confidence (range 8-9 of 10) and inter-rater reliability (99%) for fiber abnormalities came from GTNF, and interstitial abnormalities from paraffin stains (range 7-8, 99%). Vasculitic neuropathy associated with GTNF axonal degeneration (moderate to severe 79%) with OR 3.8, 95% CI (1.001-14.7), p = .04, but not significantly with the other preparations. Clinicopathologic diagnoses associated with teased fiber abnormalities in chronic inflammatory demyelinating polyradiculoneuropathy, 80% (8/10); amyloidosis, 50% (1/2); adult-onset polyglucosan disease 100% (1/1). GTNF and paraffin stains significantly correlated with fiber density determined by morphometric analysis (GTNF: OR 9.9, p < .0001, paraffin: OR 3.8, p = .03). GTNF combined with paraffin sections had highest accuracy for clinicopathologic diagnoses and fiber density with 0.86 C-stat prediction versus morphometric analysis. Pathological results lead to initiation or changes of immunotherapy in 70% (35/50; initiation n = 22, reduction n = 9, escalation n = 4) with the remaining having alternative intervention or no change. INTERPRETATION: Nerve biopsy paraffin stains combined with GTNF have highest diagnostic utility, confidence, inter-rater reliability, improving accuracy for a pathologic diagnosis aiding treatment recommendations. Immunostains and epoxy preparations are also demonstrated useful supporting consensus guidelines. This study provides class II evidence for individual nerve preparation utility.

Standards for the classification of pathogenicity of somatic variants in cancer (oncogenicity): Joint recommendations of Clinical Genome Resource (ClinGen), Cancer Genomics Consortium (CGC), and Variant Interpretation for Cancer Consortium (VICC).

PURPOSE: Several professional societies have published guidelines for the clinical interpretation of somatic variants, which specifically address diagnostic, prognostic, and therapeutic implications. Although these guidelines for the clinical interpretation of variants include data types that may be used to determine the oncogenicity of a variant (eg, population frequency, functional, and in silico data or somatic frequency), they do not provide a direct, systematic, and comprehensive set of standards and rules to classify the oncogenicity of a somatic variant. This insufficient guidance leads to inconsistent classification of rare somatic variants in cancer, generates variability in their clinical interpretation, and, importantly, affects patient care. Therefore, it is essential to address this unmet need. METHODS: Clinical Genome Resource (ClinGen) Somatic Cancer Clinical Domain Working Group and ClinGen Germline/Somatic Variant Subcommittee, the Cancer Genomics Consortium, and the Variant Interpretation for Cancer Consortium used a consensus approach to develop a standard operating procedure (SOP) for the classification of oncogenicity of somatic variants. RESULTS: This comprehensive SOP has been developed to improve consistency in somatic variant classification and has been validated on 94 somatic variants in 10 common cancer-related genes. CONCLUSION: The comprehensive SOP is now available for classification of oncogenicity of somatic variants.

Spinal cord high-grade infiltrating gliomas in adults: clinico-pathological and molecular evaluation.

Primary high-grade infiltrating gliomas of the spinal cord are rare, with prior series including limited numbers of cases and reporting poor outcomes. Additionally, the molecular profile of high-grade infiltrating gliomas of the spinal cord has not been well characterized. We identified 13 adult patients whose surgery had been performed at our institution over a 26-year-period. Radiologically, nine cases harbored regions of post-contrast enhancement. Existing slides were reviewed, and when sufficient tissue was available, immunohistochemical stains (IDH1-R132H, H3-K27M, H3K27-me3, ATRX, p53 and BRAF-V600E), and a targeted 150-gene neuro-oncology next-generation sequencing panel were performed. The 13 patients included 11 men and 2 women with a median age of 38 years (range = 18-69). Histologically, all were consistent with an infiltrating astrocytoma corresponding to 2016 WHO grades III (n = 5) and IV (n = 8). By immunohistochemistry, six cases were positive for H3K27M, all showing concomitant loss of H3K27-me3. Next-generation sequencing was successfully performed in ten cases. Next-generation sequencing studies were successfully performed in four of the cases positive for H3K27M by immunohistochemistry, and all were confirmed as H3F3A K27M-mutant. Additional recurrent mutations identified included those of TERT promoter (n = 3), TP53 (n = 5), PPM1D (n = 3), NF1 (n = 3), ATRX (n = 2), and PIK3CA (n = 2). No HIST1H3B, HIST1H3C, IDH1, IDH2, or BRAF mutations were detected. Ten patients have died since first surgery, with a median survival of 13 months and 1 year of 46%. Median survival was 48.5 months for H3K27M-positive cases, compared to 1 month for those with TERT promoter mutation and 77 months for those harboring neither (p = 0.019). Median survival for cases with TP53 mutations was 11.5 months and for those with PPM1D mutations was 84 months. Our findings suggest that high-grade infiltrating gliomas of the spinal cord in adults represent a heterogeneous group of tumors, with variable outcomes possibly related to their molecular profiles.

C9orf72 Repeat Expansion Frequency among Patients with Huntington Disease Genetic Testing.

BACKGROUND: European studies identified the C9orf72 repeat expansion as the most frequent genetic alteration in patients with Huntington disease (HD)-like phenotypes but negative HD genetic testing. OBJECTIVE: To investigate C9orf72 repeat expansion frequency in individuals tested for HD in a North American tertiary referral laboratory. METHODS: Three hundred and seventy-three cases (115 positive and 258 negative for HD) were evaluated by genotyping PCR, with follow-up Southern blot and 5' repeat methylation status assessment by combined repeat-primed and methylation-specific PCR in a subset. RESULTS: Three cases (all HD-negative) tested positive: 2 had > 2,000 repeats and were methylated, 1 had 80-100 repeats and was unmethylated. Two cases (1 HD-positive and 1 HD-negative) had intermediate alleles (20-29 repeats) and were unmethylated. The remaining 368 cases were negative (< 20 repeats). C9orf72 repeat expansion was absent in patients with HD and was identified in a small subset (1.2%) of patients with negative HD genetic testing. CONCLUSION: These findings suggest that C9orf72 repeat expansion does not coexist with HTT repeat expansion and that C9orf72 repeat expansion testing is unnecessary for patients with HD. In addition, C9orf72 evaluation may be considered for individuals negative for HD genetic testing. Similar to in previous studies, methylation of C9orf72 repeat expansion was limited to large expansions.

A Case of Long-Term Survival After Glioblastoma, IDH-Wild Type.

INTRODUCTION: Glioblastoma is a uniformly lethal primary central nervous system neoplasm. Despite the increased understanding of its pathophysiology and treatment advancements, median overall survival for patients with glioblastoma, IDH-wild type remains 14 to 21 months from diagnosis. CASE REPORT: We present the case of a 48-year-old female who presented with a focal seizure and was found to have a right frontal lobe mass on the brain magnetic resonance imaging. She underwent gross total resection and received a histological diagnosis of glioblastoma. She received radiotherapy and 6 cycles of carmustine (BCNU). Seventeen months later, she developed left hemiparesis. Imaging was concerning for tumor progression, and she was treated with 1 cycle of mechlorethamine, vincristine (oncovin), procarbazine, and prednisone (MOPP). Subsequent surveillance imaging demonstrated a therapeutic response. Twenty-seven years after her glioblastoma diagnosis, she developed status epilepticus and died from respiratory failure. Neuropathology on autopsy demonstrated extensive treatment-related changes but no evidence of recurrent glioblastoma. Genomic testing performed over 30 years after her original diagnosis revealed a profile diagnostic of glioblastoma, IDH-wild type per 2021 World Health Organization criteria. CONCLUSIONS: This patient is one of the longest-known survivors of glioblastoma, IDH-wild type, with pathologic confirmation of glioblastoma at the time of her resection and no evidence of residual disease 26 years after her last treatment. She presented with multiple factors associated with long-term glioblastoma survivorship, including female sex, young age, high Karnofsky score, and multimodal therapy. This case shows that long-term survival after glioblastoma diagnosis is possible and likely mediated through a combination of individual, tumor, and treatment factors.

Diffuse hemispheric glioma with H3 p.K28M (K27M) mutation: Unusual non-midline presentation of diffuse midline glioma, H3 K27M-altered?

Diffuse midline glioma, H3 K27-altered (DMG-H3 K27) is an aggressive group of diffuse gliomas that predominantly occurs in pediatric patients, involves midline structures, and displays loss of H3 p.K28me3 (K27me3) expression by immunohistochemistry and characteristic genetic/epigenetic profile. Rare examples of a diffuse glioma with an H3 p.K28M (K27M) mutation and without involvement of the midline structures, so-called "diffuse hemispheric glioma with H3 p.K28M (K27M) mutation" (DHG-H3 K27), have been reported. Herein, we describe 2 additional cases of radiologically confirmed DHG-H3 K27 and summarize previously reported cases. We performed histological, immunohistochemical, molecular, and DNA methylation analysis and provided clinical follow-up in both cases. Overall, DHG-H3 K27 is an unusual group of diffuse gliomas that shows similar clinical, histopathological, genomic, and epigenetic features to DMG-H3 K27 as well as enrichment for activating alterations in MAPK pathway genes. These findings suggest that DHG-H3 K27 is closely related to DMG-H3 K27 and may represent an unusual presentation of DMG-H3 K27 without apparent midline involvement and with frequent MAPK pathway activation. Detailed reports of additional cases with clinical follow-up will be important to expand our understanding of this unusual group of diffuse gliomas and to better define the clinical outcome and how to classify DHG-H3 K27.

Shared gene expression alterations in prostate cancer and histologically benign prostate from patients with prostate cancer.

Prostate cancer (PCa) field effect alterations provide important clues regarding the initiation of these tumors and suggest targets for prevention or biomarkers for early detection. However, biomarkers of PCa field effects that have passed independent validation are lacking, largely because these alterations are subtle and difficult to distinguish from unrelated small changes in gene expression. We hypothesized that shared expression alterations in PCa and benign prostates containing PCa (BPCs) would have a higher potential for independent validation than alterations identified in BPCs alone. Expression analyses were performed on 37 PCas and 36 unmatched BPCs and were contrasted with 28 benign prostates (BPs) from patients free of PCa. Most of the protein-coding genes and nonexonic RNAs selected according to the hypothesis were validated by quantitative RT-PCR in an independent set of 51 BPCs and BPs. A statistical model based on two markers distinguished BPCs from BPs in the RT-PCR set and in an external microarray (area under the curve = 0.84 and 0.90, respectively). In addition, genes with predominant expression in stroma were identified by expression profiling of pure stroma and epithelial cells. Pathway analysis identified dysregulated platelet-derived growth factor receptor signaling in BPC stroma. These results validate our approach for finding PCa field effect alterations and demonstrate a PCa transcriptome fingerprint in nonneoplastic cells in prostates containing cancer.

False-negative dual-energy computed tomography in a patient with acute gout.

Gout is a painful inflammatory arthropathy caused by crystallization of monosodium urate within the joints. We present the case of a patient with primary gout who had positive results of joint aspiration and synovial biopsy for monosodium urate crystals in the third metacarpophalangeal joint but false-negative results of dual-energy computed tomography.

BAP1 Immunostain Status in Intraocular Biopsy Specimens for Uveal Melanoma Highly Correlates with Other Prognostic Markers.

Introduction: Loss of BAP1 protein expression emerged as a negative prognostic marker in uveal melanoma (UM) and has primarily been studied in enucleations. Intraocular biopsy is frequently performed prior to UM globe-conserving therapy. Methods: We retrospectively evaluated BAP1 immunostaining of UM in 16 biopsies and 8 subsequent enucleations, and results were correlated with the UM-specific gene expression profile (GEP; n = 11), chromosome 3 status by FISH and/or chromosomal microarray (n = 12; 9 also had GEP), and clinical outcomes. Results: UM involved the choroid in 15 (of 16) cases. Biopsy was performed for prognostication (n = 12) or diagnosis (n = 4). Treatment included brachytherapy (n = 13; 5 followed by enucleation) or enucleation only (n = 3). BAP1 nuclear immunostaining was positive in 9, negative in 4, and equivocal in 3 biopsies. For the 3 equivocal biopsies, BAP1 immunostaining was positive in 2 (of 3) subsequent enucleations. BAP1 immunostaining was concordant between all 5 remaining biopsies and enucleations. BAP1-positive biopsies had disomy 3 (n = 6) or 3p loss (n = 1) and class 1 GEP (n = 6). BAP1-negative biopsies had monosomy 3 (n = 3) and class 2 GEP (n = 2). Median follow-up was 62.5 months (range, 17-150). For BAP1-positive UM patients, 8 were alive (7 without metastatic disease) and 3 had died (1 melanoma-related death). Among BAP1-negative UM patients, 2 were alive (1 with metastatic disease) and 3 had melanoma-related deaths. Conclusion: BAP1 immunostaining in biopsies highly correlates with results in subsequent enucleations and with well-established UM prognostic markers, representing a potential additional prognostic tool for UM biopsies.

Cyclin D1 Expression and Molecular Genetic Findings in Periocular Histiocytoses and Neoplasms of Macrophage-Dendritic Cell Lineage.

PURPOSE: Frequent activating mutations in the mitogen-activated protein kinase (MAPK) pathway genes have been identified in histiocytoses. MAPK signaling consistently upregulates cyclin D1. The goal of this study was to determine whether cyclin D1 expression by immunohistochemistry is a useful diagnostic marker for periocular histiocytoses and to further characterize their genetic basis. DESIGN: Retrospective observational case series. METHODS: Pathology records were searched for all patients with histiocytoses diagnosed between 1995 and 2020. Eleven histiocyte-rich inflammatory lesions and 10 xanthelasma served as controls. Cyclin D1 immunohistochemistry was performed on all tissues. A subset of histiocytoses was evaluated by next-generation sequencing (NGS) and droplet digital PCR (ddPCR). RESULTS: There were 36 patients, 15 males (42%) and 21 females (58%), with histiocytoses: 9 juvenile xanthogranuloma (25%), 8 adult-onset asthma and periocular xanthogranuloma (22%), 7 Langerhans cell histiocytosis (19%), 5 Rosai-Dorfman disease (14%), 5 xanthogranuloma-not otherwise specified (14%), 1 Erdheim-Chester disease (3%), and 1 histiocytic sarcoma (3%). Moderate to strong nuclear cyclin D1 expression was present in ≥50% of lesional cells in histiocytoses (23/36, 64%), significantly more when compared to histiocyte-rich inflammatory lesions (0/11, 0%, P<.001) and xanthelasma (0/10, 0%, P<.001). Cyclin D1 was expressed in <10% of lesional cells in all 11 histiocyte-rich inflammatory lesions (P<.001) and all 10 xanthelasma lesions (P<.001). MAPK pathway gene mutations were detected in 12 of 14 (86%) histiocytoses successfully assayed by NGS and/or ddPCR. CONCLUSIONS: Our study confirms that the cyclin D1 immunohistochemical stain is a useful diagnostic marker for periocular histiocytoses, correlating with underlying mutations in MAPK pathway genes.

What Every Neuropathologist Needs to Know: Practical Aspects and Pitfalls in Molecular Diagnosis of Brain Tumors.

Molecular testing has become part of the routine diagnostic workup of brain tumors after the implementation of integrated histomolecular diagnoses in the 2016 WHO classification update. It is important for every neuropathologist to be aware of practical preanalytical, analytical, and postanalytical factors that impact the performance and interpretation of molecular tests. Prior to testing, optimizing tumor purity and tumor amount increases the ability of the molecular test to detect the genetic alteration of interest. Recognizing basic molecular testing platform analytical characteristics allows selection of the optimal platform for each clinicopathological scenario. Finally, postanalytical considerations to properly interpret molecular test results include understanding the clinical significance of the detected genetic alteration, recognizing that detected clinically significant genetic alterations are occasionally germline constitutional rather than somatic tumor-specific, and being cognizant that recommended and commonly used genetic nomenclature may differ. Potential pitfalls in brain tumor molecular diagnosis are also discussed.

Gene Fusions in Ocular Adnexal Tumors.

PURPOSE: To highlight the increasing importance of gene fusions in the diagnosis, prognosis, and therapy of ocular adnexal tumors. DESIGN: Perspective. METHODS: A focused review of gene fusions, their pathogenic mechanism, and gene fusion detection methods in lacrimal gland and primary orbital and ocular adnexal soft tissue tumors; reappraisal of diagnostic, prognostic, and therapeutic approach to ocular adnexal tumors in light of emerging molecular genetic data. RESULTS: The widespread implementation of fluorescence in situ hybridization and next-generation sequencing methods in pathology practice has led to identification of recurrent gene rearrangements and fusions in a variety of tumors. As a result, molecular genetic methods have become the gold standard for diagnosis of tumors with overlapping histology and immunophenotype, such as small round blue cell tumors. Identification of canonic gene fusions has led to development of sensitive and specific immunohistochemical markers, such as STAT6 in solitary fibrous tumor. In addition to diagnostic accuracy, gene fusions have prognostic implications, such as unfavorable prognosis of PAX3-FOXO1 fusion in alveolar rhabdomyosarcoma. Finally, recognition of gene fusions as a driving mechanism in neoplasia has led to development of U.S. Food and Drug Administration-approved targeted therapies, such as TRK inhibitors for NTRK fusion-positive cancers. CONCLUSION: The discovery of recurrent gene fusions in various tumors, including those involving ocular adnexa, has led to a deeper insight into the molecular mechanisms of these neoplasms, revolutionizing our approach to their diagnosis, prognostication, and therapy.

Carbon Fiducial Markers for Tumor Localization in Stereotactic Irradiation of Uveal Melanoma.

PURPOSE: The aim of this study was to demonstrate the role of carbon fiducial markers (fiducials) for guiding radiotherapy in the management of uveal melanoma (UM). METHODS: This is a retrospective interventional case series at a single-center ocular oncology practice. The medical records were reviewed retrospectively for all patients with UM treated with stereotactic radiosurgery using episcleral fiducials. We report our short-term experience with surgical placement of fiducials, UM localization, treatment outcomes, and optimization approaches. RESULTS: We evaluated 11 cases of UM (mean age: 65 years; 64% female). The placed fiducials were numbered from 2 to 4, each secured to the sclera with a surgical microscope or surgical loupes and either 5-0 or 8-0 nylon sutures at 50% scleral depth and 3 mm beyond the tumor margin. Over a median follow-up of 11 months (range: 4.2-43.2 months), no recurrences of intraocular UM were observed. One case of enucleation after stereotactic radiosurgery developed because of radiation-related surface irritation, ocular dryness, and secondary keratopathy. Two patients (18%) with 5-0 nylon sutures required fiducial removal because of suture exposure, successfully accomplished in an outpatient setting. CONCLUSIONS: Fiducials represent a viable alternative to tantalum rings for guiding stereotactic radiotherapy to manage UM and provide additional definition of the tumor border with linear orientation that helps optimize targeted radiation delivery. Fiducial placement with a 3-mm margin from the visible tumor border should not result in clinically important radiation dose attenuation at the tumor margins. Anteriorly placed fiducials may cause discomfort, yet they are easily removed in the outpatient setting.

Diffuse Gliomas of the Brainstem and Cerebellum in Adults Show Molecular Heterogeneity.

Posterior fossa (PF) diffuse gliomas in pediatric patients frequently harbor the H3 K27M mutation. Among adults, PF diffuse gliomas are rare, with limited data regarding molecular features and clinical outcomes. We identified 28 adult PF diffuse glioma patients (17 males; median: 50 y, range: 19 to 78 y), with surgery performed at our institution (13 brainstem; 15 cerebellum). Histologic subtypes included anaplastic astrocytoma (n=21), glioblastoma (n=6), and diffuse astrocytoma (n=1). Immunohistochemistry was performed for H3 K27M (n=26), IDH1-R132H (n=28), and ATRX (n=28). A 150-gene neuro-oncology-targeted next-generation sequencing panel was attempted in 24/28, with sufficient informative material in 15 (51.7%). Tumors comprised 4 distinct groups: driver mutations in H3F3A (brainstem=4; cerebellum=2), IDH1 (brainstem=4; cerebellum=4), TERT promotor mutation (brainstem=0; cerebellum=3), and none of these (n=5), with the latter harboring mutations of TP53, PDGFRA, ATRX, NF1, and RB1. All TERT promoter-mutant cases were IDH-wild-type and arose within the cerebellum. To date, 20 patients have died of disease, with a median survival of 16.3 months, 1-year survival of 67.5%. Median survival within the subgroups included: H3F3A=16.4 months, IDH mutant=113.4 months, and TERT promoter mutant=12.9 months. These findings suggest that PF diffuse gliomas affecting adults show molecular heterogeneity, which may be associated with patient outcomes and possible response to therapy, and supports the utility of molecular testing in these tumors.

Polymorphous Low-Grade Neuroepithelial Tumor of the Young (PLNTY): Molecular Profiling Confirms Frequent MAPK Pathway Activation.

Polymorphous low-grade neuroepithelial tumor of the young (PLNTY) is a recently described epileptogenic tumor characterized by oligodendroglioma-like components, aberrant CD34 expression, and frequent mitogen-activated protein kinase (MAPK) pathway activation. We molecularly profiled 13 cases with diagnostic histopathological features of PLNTY (10 female; median age, 16 years; range, 5-52). Patients frequently presented with seizures (9 of 12 with available history) and temporal lobe tumors (9 of 13). MAPK pathway activating alterations were identified in all 13 cases. Fusions were present in the 7 youngest patients: FGFR2-CTNNA3 (n = 2), FGFR2-KIAA1598 (FGFR2-SHTN1) (n = 1), FGFR2-INA (n = 1), FGFR2-MPRIP (n = 1), QKI-NTRK2 (n = 1), and KIAA1549-BRAF (n = 1). BRAF V600E mutation was present in 6 patients (17 years or older). Two fusion-positive cases additionally harbored TP53/RB1 abnormalities suggesting biallelic inactivation. Copy number changes predominantly involving whole chromosomes were observed in all 10 evaluated cases, with losses of chromosome 10q occurring with FGFR2-KIAA1598 (SHTN1)/CTNNA3 fusions. The KIAA1549-BRAF and QKI-NTRK2 fusions were associated respectively with a 7q34 deletion and 9q21 duplication. This study shows that despite its name, PLNTY also occurs in older adults, who frequently show BRAF V600E mutation. It also expands the spectrum of the MAPK pathway activating alterations associated with PLNTY and demonstrates recurrent chromosomal copy number changes consistent with chromosomal instability.

Case Report with Review of the Literature: Uveal Melanoma in a Patient with Carney Complex - Another Rare Component of the Syndrome?

A 74-year-old woman with Carney complex (CNC) and complaints of poor vision was found, on ophthalmic examination, to have a pigmented tumor involving the peripheral choroid and ciliary body in her right eye. The eye was enucleated and showed a ciliochoroidal melanoma with marked pleomorphism. The tumor did not recur or metastasize after almost 10 years of follow-up, and the patient died of unrelated causes. Molecular studies revealed a complex genome with multiple whole-chromosome losses including monosomy of chromosomes 1, 2 (including loss of CNC2at 2p16), 14, 17 (including loss of a copy of PRAKA1 at 17q24.2), 18, 19, 21, 22, and X. No monosomy 3 was observed. This is only the second case of uveal melanoma in a patient with CNC, raising the possibility that this might represent a rare component of this syndrome.

Frequency of false-positive FISH 1p/19q codeletion in adult diffuse astrocytic gliomas.

BACKGROUND: Oligodendroglioma is genetically defined by concomitant IDH (IDH1/IDH2) mutation and whole-arm 1p/19q codeletion. Codeletion of 1p/19q traditionally evaluated by fluorescence in situ hybridization (FISH) cannot distinguish partial from whole-arm 1p/19q codeletion. Partial 1p/19q codeletion called positive by FISH is diagnostically a "false-positive" result. Chromosomal microarray (CMA) discriminates partial from whole-arm 1p/19q codeletion. Herein, we aimed to estimate the frequency of partial 1p/19q codeletion that would lead to a false-positive FISH result. METHODS: FISH 1p/19q codeletion test probe coordinates were mapped onto Oncoscan CMA data to determine the rate of partial 1p/19q codeletion predicted to be positive by FISH. Diffuse astrocytic gliomas with available CMA data (2015-2018) were evaluated and classified based on IDH1-R132H/ATRX/p53 immunohistochemistry, IDH/TERT promoter targeted sequencing, and/or CMA according to classification updates. Predicted false-positive cases were verified by FISH whenever possible. RESULTS: The overall estimated false-positive FISH 1p/19q codeletion rate was 3.6% (8/223). Predicted false positives were verified by FISH in 6 (of 8) cases. False-positive rates did not differ significantly (P = .49) between IDH-mutant (4.6%; 4/86) and IDH-wildtype (2.9%; 4/137) tumors. IDH-wildtype false positives were all WHO grade IV, whereas IDH-mutant false positives spanned WHO grades II-IV. Testing for 1p/19q codeletion would not have been indicated for most false positives based on current classification recommendations. CONCLUSION: Selective 1p/19q codeletion testing and cautious interpretation for conflicting FISH and histopathological findings are recommended to avoid potential misdiagnosis.