Summary Background Gastrointestinal stromal tumour is the most common sarcoma of the intestinal tract. Imatinib mesylate is a small molecule that inhibits activation of the KIT and platelet-derived ...growth factor receptor α proteins, and is effective in first-line treatment of metastatic gastrointestinal stromal tumour. We postulated that adjuvant treatment with imatinib would improve recurrence-free survival compared with placebo after resection of localised, primary gastrointestinal stromal tumour. Methods We undertook a randomised phase III, double-blind, placebo-controlled, multicentre trial. Eligible patients had complete gross resection of a primary gastrointestinal stromal tumour at least 3 cm in size and positive for the KIT protein by immunohistochemistry. Patients were randomly assigned, by a stratified biased coin design, to imatinib 400 mg (n=359) or to placebo (n=354) daily for 1 year after surgical resection. Patients and investigators were blinded to the treatment group. Patients assigned to placebo were eligible to crossover to imatinib treatment in the event of tumour recurrence. The primary endpoint was recurrence-free survival, and analysis was by intention to treat. Accrual was stopped early because the trial results crossed the interim analysis efficacy boundary for recurrence-free survival. This study is registered with ClinicalTrials.gov , number NCT00041197. Findings All randomised patients were included in the analysis. At median follow-up of 19·7 months (minimum–maximum 0–56·4), 30 (8%) patients in the imatinib group and 70 (20%) in the placebo group had had tumour recurrence or had died. Imatinib significantly improved recurrence-free survival compared with placebo (98% 95% CI 96–100 vs 83% 78–88 at 1 year; hazard ratio HR 0·35 0·22–0·53; one-sided p<0·0001). Adjuvant imatinib was well tolerated, with the most common serious events being dermatitis (11 3% vs 0), abdominal pain (12 3% vs six 1%), and diarrhoea (ten 2% vs five 1%) in the imatinib group and hyperglycaemia (two <1% vs seven 2%) in the placebo group. Interpretation Adjuvant imatinib therapy is safe and seems to improve recurrence-free survival compared with placebo after the resection of primary gastrointestinal stromal tumour. Funding US National Institutes of Health and Novartis Pharmaceuticals.
Summary Carcinoma ex-pleomorphic adenoma (CA ex-PA) is a malignant salivary gland tumor that arises in association with pleomorphic adenoma (PA). Both PA and CA ex-PA have a broad spectrum of ...histology, and distinction from their histologic mimics may be difficult based on morphology alone. PLAG1 and HMGA2 abnormalities are the most common genetic events in both PA and CA ex-PA; however, the use of PLAG1 and HMGA2 as adjunct molecular tests has not been well established. Fluorescence in situ hybridization for PLAG1 and HMGA2 was performed on 22 CA ex-PA (10 myoepithelial carcinomas MECAs, 10 salivary duct carcinomas SDCs, 1 carcinoma with squamoglandular features, and 1 mixed MECA-adenocarcinoma not otherwise specified), 20 de novo carcinomas (11 MECAs and 9 SDCs), 16 PAs, and 11 PA-histologic mimics. All except 3 CAs ex-PA (86%) were positive for PLAG1 or HMGA2 rearrangements/amplifications. In contrast, 18 (90%) of 20 de novo carcinomas lacked abnormalities in PLAG1 or HMGA2 ( P < .01). PLAG1 or HMGA2 rearrangements were identified in 6 (67%) of 9 hypocellular myxoid PAs and in 2 (29%) of 7 cellular PAs. Furthermore, all morphologic mimics of PA were negative for PLAG1 or HMGA2. PLAG1 and HMGA2 rearrangements are the most common genetic events in CA ex-PA regardless of the histologic subtype. Unlike CA ex-PA, de novo carcinomas were negative for PLAG1 and HMGA2 . Interestingly, rearrangements of PLAG1 / HMGA2 were identified in most hypocellular PAs but only in a small subset of cellular PAs. Fluorescence in situ hybridization for PLAG1 or HMGA2 can be used to distinguish between PA and CA ex-PA and their morphologic mimics.
Background Little is known about the outcomes of patients with microscopically positive (R1) resections for primary gastrointestinal stromal tumors (GIST) because existing retrospective series ...contain small numbers of patients. The objective of this study was to analyze factors associated with R1 resection and assess the risk of recurrence with and without imatinib. Study Design We reviewed operative and pathology reports for 819 patients undergoing resection of primary GIST from the North American branch of the American College of Surgeons Oncology Group (ACOSOG) Z9000 and Z9001 clinical trials at 230 institutions testing adjuvant imatinib after resection of primary GIST. Patient, tumor, operative characteristics, factors associated with R1 resections, and disease status were analyzed. Results Seventy-two (8.8%) patients had an R1 resection and were followed for a median of 49 months. Factors associated with R1 resection included tumor size (≥10 cm), location (rectum), and tumor rupture. The risk of disease recurrence in R1 patients was driven largely by the presence of tumor rupture. There was no significant difference in recurrence-free survival for patients undergoing an R1 vs R0 resection of GIST with (hazard ratio HR 1.095, 95% CI 0.66, 1.82, p = 0.73) or without (HR 1.51, 95% CI 0.76, 2.99, p = 0.24) adjuvant imatinib. Conclusions Approximately 9% of 819 GIST patients had an R1 resection. Significant factors associated with R1 resection include tumor size ≥ 10 cm, location, and rupture. The difference in recurrence-free survival with or without imatinib therapy in those undergoing an R1 vs R0 resection was not statistically significant at a median follow-up of 4 years.
Biphenotypic sinonasal sarcoma (BSNS) is a recently recognized low-grade sarcoma that exhibits both neural and myogenic differentiation. This unique dual phenotype stems from recurrent rearrangements ...in PAX3 , a transcription factor that promotes commitment along both lineages. While identification of PAX3 rearrangements by fluorescence in situ hybridization (FISH) can confirm a BSNS diagnosis, this assay is not widely available. This study evaluates whether an expanded immunohistochemical panel can facilitate recognition of BSNS without molecular analysis. Eleven cases of BSNS were identified from the surgical pathology archives of two academic medical centers. In 8 cases, the diagnosis was confirmed by FISH using custom probes for PAX3. In 3 cases FISH failed but histologic and immunophenotypic findings were diagnostic for BSNS. All 11 BSNS (100%) were at least focally positive for S100 as well as calponin and/or smooth muscle actin. In addition, 10 of 11 (91%) expressed nuclear β-catenin, 8 of 10 (80%) expressed factor XIIIa, 4 of 11 (36%) expressed desmin, and 3 of 10 (30%) expressed myogenin. All 11 tumors were negative for SOX10. While no single marker resolves immunohistochemical overlap between BSNS and its histologic mimickers such as nerve sheath tumors, an extended immunohistochemical panel that includes β-catenin and SOX10 helps to support the diagnosis of BSNS without the need for gene rearrangement studies.
Summary Background Adjuvant imatinib mesylate prolongs recurrence-free survival (RFS) after resection of localised primary gastrointestinal stromal tumours (GIST). We aimed to develop a nomogram to ...predict RFS after surgery in the absence of adjuvant therapy to help guide patient selection for adjuvant imatinib therapy. Methods A nomogram to predict RFS based on tumour size (cm), location (stomach, small intestine, colon/rectum, or other), and mitotic index (<5 or ≥5 mitoses per 50 high-power fields) was developed from 127 patients treated at Memorial Sloan-Kettering Cancer Center (MSKCC), New York, NY, USA. The nomogram was tested in patients from the Spanish Group for Research on Sarcomas (GEIS; n=212) and the Mayo Clinic, Rochester, MN, USA (Mayo; n=148). The nomogram was assessed by calculating concordance probabilities and testing calibration of predicted RFS with observed RFS. Concordance probabilities were also compared with those of three commonly used staging systems. Findings The nomogram had a concordance probability of 0·78 (SE 0·02) in the MSKCC dataset, and 0·76 (0·03) and 0·80 (0·02) in the validation cohorts. Nomogram predictions were well calibrated. Inclusion of tyrosine kinase mutation status in the nomogram did not improve its discriminatory ability. Concordance probabilities of the nomogram were better than those of the two NIH staging systems (0·76 0·03 vs 0·70 0·04, p=0·04 and 0·66 0·04, p=0·01 in the GEIS validation cohort; 0·80 0·02 vs 0·74 0·02, p=0·04 and 0·78 0·02, p=0·05 in the Mayo cohort) and similar to those of the AFIP-Miettinen staging system (0·76 0·03 vs 0·73 0·004, p=0·28 in the GEIS cohort; 0·80 0·02 vs 0·76 0·003, p=0·09 in the Mayo cohort). Nomogram predictions of RFS seemed better calibrated than predictions made with the AFIP-Miettinen system. Interpretation The nomogram accurately predicts RFS after resection of localised primary GIST and could be used to select patients for adjuvant imatinib therapy. Funding National Cancer Institute, Bethesda, MD, USA.
Summary Background Preclinical studies have shown synergistic antitumour activity by inhibition of insulin-like growth factor-1 receptor (IGF-1R) and mTOR. The expression of IGF-1R seems to be ...crucial for this effect. We investigated the safety and efficacy of the combination of the IGF-1R antibody cixutumumab and the mTOR inhibitor temsirolimus in patients with chemotherapy-refractory bone and soft-tissue sarcomas according to IGF-1R expression by immunohistochemistry. Methods We undertook a multicentre, open-label, phase 2 study in 19 cancer centres in the USA. Patients aged at least 16 years with a histologically confirmed diagnosis of bone or soft-tissue sarcoma were allocated on the basis of IGF-1R expression by immunohistochemistry to one of three treatment groups: IGF-1R-positive soft-tissue sarcoma (group A), IGF-1R-positive bone sarcomas (group B), or IGF-1R-negative bone and soft-tissue sarcoma (group C). Patients received weekly treatment with cixutumumab (6 mg/kg, intravenous) and temsirolimus (25 mg, intravenous flat dose) in 6-week cycles. A Simon optimal two-stage design was used for every arm. The primary endpoint was progression-free survival (PFS) at 12 weeks by intention-to-treat analysis in the first 54 patients assigned to every treatment arm. Although patients still remain on treatment, this trial has completed enrolment and this represents the final analysis. This study is registered with ClinicalTrials.gov , number NCT01016015. Findings Between Nov 18, 2009, and April 11, 2012, 388 patients were screened for IGF-1R expression and 54 were assigned to each arm. 17 of 54 patients in the IGF-1R-positive soft-tissue sarcoma group (31%; one-sided 95% CI lower bound 21%; two-sided 90% CI 21–43), 19 of 54 in IGF-1R-positive bone sarcoma group (35%; one-sided 95% CI lower bound 24%; two-sided 90% CI 24–47), and 21 of 54 in the IGF-1R-negative group (39%, one-sided 95% CI lower bound 28%; two-sided 90% CI 28–51) were progression free at 12 weeks. On April 6, 2011, the protocol was amended to include three additional patients in the IGF-1R-positive soft-tissue sarcoma group (total of 57 patients) and nine more in the IGF-1R-negative group (total of 63 patients). There were 2546 adverse events reported during the study, 214 (8%) of which were grade 3–4. The most common grade 3–4 toxicities in the 174 treated patients were anaemia in 16 (9%) patients, hyperglycaemia in 18 (10%), hypophosphataemia in 16 (9%), lymphopenia in 25 (14%), oral mucositis in 19 (11%), and thrombocytopenia in 19 (11%). Interpretation The combination of cixutumumab and temsirolimus shows clinical activity in patients with sarcoma and forms a basis for future trials. However, IGF-1R expression by immunohistochemistry is not predictive of clinical outcome after treatment with this combination. Funding National Cancer Institute and CycleforSurvival Fund, Memorial Sloan-Kettering Cancer Center.
Summary Extraskeletal myxoid chondrosarcomas (EMC) are rare soft tissue sarcomas with distinctive histology and uncertain histogenesis, characterized by Ewing sarcoma breakpoint region 1–nuclear ...receptor subfamily 4, group A, member 3 ( EWSR1 - NR4A3 ) fusion in 75% of the cases. A smaller proportion of cases show NR4A3 fused to other gene partners including TATA binding protein–associated factor 15 ( TAF15 ), transcription factor 12 ( TCF12 ), and TRK-fused gene (TFG). The impact of various gene fusions on morphology and outcome has not been previously evaluated. We investigated 26 consecutive EMCs and correlated the genetic findings with morphology and clinical outcome. There were 5 females and 21 males (median age, 49.5 years). Mean size of the tumors was 11 cm. Fluorescence in situ hybridization analysis showed EWSR1 - NR4A3 gene fusion in 16 cases (62%), TAF15 - NR4A3 gene fusion in 7 cases (27%), and TCF12 - NR4A3 gene fusion in 1 case (4%). Two cases showed only NR4A3 gene rearrangements. Morphologically, most EWSR1 -rearranged tumors (10/16) showed low cellularity, minimal cytologic atypia, and low mitotic counts. In contrast, 80% of EMCs with variant (non- EWSR1 ) NR4A3 gene fusions ( TAF15 , TCF12 ) had high-grade morphology with increased cellularity, proliferation, and cytologic atypia, showing a plasmacytoid/rhabdoid morphology in half the cases. Follow-up showed that only 1 of 16 patients with EWSR1 -rearranged tumors died of disease, in contrast to 3 (43%) of 7 TAF15 -rearranged tumors. In conclusion, EMCs with variant NR4A3 gene fusions show a higher incidence of rhabdoid phenotype, high-grade morphology, and a more aggressive outcome compared with the EWSR1 - NR4A3 positive tumors. Furthermore, fluorescence in situ hybridization assay for NR4A3 , along with EWSR1 , may be an additional ancillary test to confirm diagnosis of EMCs.
Summary Giant cell reparative granulomas (GCRGs) are lytic lesions that occur predominantly in the gnathic bones and occasionally in the small bones of the hands and feet. They are morphologically ...indistinguishable from, and are regarded as synonymous with, solid variant of aneurysmal bone cysts (ABC) in extragnathic sites. Identification of USP6 gene rearrangements in primary ABC has made possible investigating potential pathogenetic relationships with other morphologic mimics. USP6 gene alterations in giant cell–rich lesions (GCRG/ABC) of small bones of the hands and feet have not been previously studied. We investigated USP6 gene alterations in a group of 9 giant cell–rich lesions of the hands and feet and compared the findings with morphologically similar lesions including 8 gnathic GCRGs, 22 primary ABCs, 8 giant cell tumors of bone, and 2 brown tumors of hyperparathyroidism. Overall, there were 49 samples from 48 patients including 26 females and 22 males. Of the 9 lesions of the hands and feet, 8 (89%) showed USP6 gene rearrangements, whereas no abnormalities were identified in the 8 gnathic GCRGs, 2 brown tumors, or 8 giant cell tumors of bone. Of the 22 primary ABCs, 13 (59%) showed USP6 gene rearrangements. In conclusion, most GCRGs of the hands and feet represent true ABCs and should be classified as such. The terminology of GCRG should be limited to lesions from gnathic location. Fluorescence in situ hybridization for USP6 break-apart is a useful ancillary tool in the diagnosis of primary ABCs and distinguishing them from GCRGs and other morphologically similar lesions.
Summary Neurofibromatosis 1 (NF1) patients develop multiple neurofibromas, with 8-15% of patients experiencing malignant peripheral nerve sheath tumor (MPNST) during their lifetime. Prediction of ...transformation, typically from plexiform neurofibroma, is clinically and histologically challenging. In this overview, following a consensus meeting in October 2016, we outline the histopathologic features and molecular mechanisms involved in the malignant trans-formation of neurofibromas. Nuclear atypia alone is generally insignificant. However, with atypia, loss of neurofibroma architecture, high cellularity, and/or mitotic activity >1/50 but <3/10 high power fields, the findings are worrisome for malignancy. We propose the term “atypical neurofibromatous neoplasms of uncertain biologic potential (ANNUBP)” for lesions displaying at least two of these features. This diagnosis should prompt additional sampling, clinical correlation, and possibly, expert pathology consultation. Currently such tumors are diagnosed inconsistently as atypical neurofibroma or low-grade MPNST. Most MPNSTs arising from neurofibromas are high-grade sarcomas and pose little diagnostic difficulty, although rare non-necrotic tumors with 3-9 mitoses/10 HPFs can be recognized as low-grade variants. While neurofibromas contain numerous S100 protein/SOX10-positive Schwann cells and CD34-positive fibroblasts, both components are reduced or absent in MPNST. Loss of p16/ CDKN2A expression, elevated Ki67 labeling, and extensive nuclear p53 positivity are also features of MPNST that can to some degree already occur in ANNUBP. Complete loss of trimethylated histone 3 lysine 27 (H3K27me3) expression is potentially more reliable, being immunohisto-chemically detectable in about half of MPNSTs. Correlated clinicopathologic, radiologic, and genetic studies should increase our understanding of malignant transformation in neurofibromas, hopefully improving diagnosis and treatment soon.
Clear cell odontogenic carcinoma (CCOC) is a rare odontogenic tumor of the jaws that is more common in the mandible than maxilla and has a female preponderance with a peak incidence in the sixth ...decade. It is characterized by locally aggressive behavior and has the potential to metastasize. This tumor was recently reported to have a rearrangement of the Ewing sarcoma breakpoint region 1 gene (EWS RNA-binding protein 1, EWSR1 ) in 5 of 8 cases tested and of the activating transcription factor 1 gene ( ATF1 ) in 1 case tested. We report a case of CCOC in the premolar area of the mandible in a 59-year-old woman. This case demonstrated the presence of both EWSR1 and ATF1 gene rearrangements by fluorescence in situ hybridization.
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