M Miettinen

..Their pathogenesis may differ from that of adult GISTs because no KIT or PDGFRA mutations were found; connection with Carney triad seems infrequent despite demographic and histologic similarities...

..KIT positive Cajal cells were not found in normal omental tissues failing to support the presence of these ancestral cells for GIST in the omentum...

..These tumors are phenotypically similar to peripheral glomus tumors and differ from epithelioid GISTs...

..The number of LMS cases is too small for stratification for risk assessment. True SMTs of small intestine should be separated from GISTs because of different pathogenesis and treatment...

..When OFT is strictly defined by the criteria noted above, there is potential for local recurrence, but there seems to be little or no risk for metastasis...

..These tumors most commonly occur in the stomach and small intestine and encompass a clinical spectrum from benign to malignant. In the current study, the authors examined long-term follow-up data of 1892 GIST patients from the U.S...

..Immunohistochemical demonstration of KIT, CD34, or protein kinase theta positivity helps to properly identify these tumors...

..Functional analysis of the different c-kit mutations and their impact on the response to tyrosine kinase inhibitors are under intense investigation...

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..Among epithelial tumors, ERG shows a great promise as a marker to identify prostatic carcinoma in both primary and metastatic settings...

..They are believed to originate from interstitial cells of Cajal or related stem cells...

..The great majority of duodenal mesenchymal tumors are GISTs, which have a spectrum from small indolent tumors to overt sarcomas. LMs and LMSs are rare...

..It needs to be distinguished from Rosai-Dorfman disease, juvenile xanthogranuloma, a variety of granulomatous conditions, and some malignant neoplasms, including histiocytic sarcoma, melanoma, and epithelioid sarcoma...

..There were no PDGFRA exon 12 or 8 mutations. Systematic data on prognosis of small intestinal GISTs of various size and mitotic activity categories can be helpful in management and surveillance of patients with these tumors...

..Majority of these mutations are in-frame-deletions and missense mutations clustering in the 5'-end of juxtamembrane domain (exon 11). A rare mutation, an Ala502-Tyr503 duplication in exon 9, is specific for intestinal GISTs...

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..This review summarizes the current knowledge, guidelines, prognostic data and controversies for the classification of SMTs of soft tissue and most visceral sites...

..Intramural LMs are exceptional, and true LMSs are rare, and similar to colonic ones, often present as intraluminal polypoid masses that appear to have a better prognosis than GISTs with similar mitotic rates...

..This report documents the rare occurrence of CD117-positive GISTs as primary appendiceal tumors...

..Angiosarcomas and metastatic melanomas, both of which are often KIT-positive, should not be confused with GISTs...

..None of the 16 tumors from 15 patients had a KIT exon 9, 11, 13, or 17 or PDGFRA exon 12 or 18 mutation as is typically seen in sporadic GISTs, indicating that GISTs in NF1 patients have a different pathogenesis than sporadic GISTs...

..5, 5, and 14 years. Because these tumors have some resemblance to blastomas of other organs, we propose the term "gastroblastoma" for this distinctive, at least low-grade malignant epitheliomesenchymal tumor of the stomach...

..DOG1 should be added into the diagnostic panel evaluating GI and other abdominal tumors, but limitations in its sensitivity and specificity should be recognized...

..Plexiform fibromyxoma is a distinctive benign gastric antral neoplasm that should be separated from GIST, nerve sheath tumors, and other fibromyxoid neoplasms...

..Snare polypectomy is an adequate treatment, but ensuring the complete removal and follow-up are necessary precautions for tumors with any atypia or mitotic activity...

..Microphthalmia transcription factor may be a valuable addition to the marker panel used in diagnosing melanoma, in combination with S100, TYR, and the other markers, but it is not present in cases of desmoplastic melanomas...

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..Global expression of K7 and K19 in mesotheliomas versus focal expression in monophasic and poorly differentiated SSs, and differential patterns of K14 expression may also be helpful...

..These observations may reflect the different pathways leading to malignant transformation of GISTs...

..The unexpected K1 immunoreactivity in nonvascular soft tissue tumors, such as synovial sarcoma, epithelioid sarcoma, and schwannomas, requires further study...

..Genetic markers, including DNA-copy number changes, telomerase activity, and KIT mutation status, may be useful in more accurately identifying tumors with malignant potential...

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..Most of these tumors resemble uterine leiomyomas by histology and positive hormone receptors, and they seem to have a good long-term prognosis with a small potential for local recurrence...

..Synovial sarcoma rarely occurs as a gastric primary tumor. It has a variable prognosis depending on tumor size and differentiation, and should be considered in the differential diagnosis of KIT-negative gastric spindle cell neoplasms...

..The above results may be helpful for setting the criteria for adjuvant treatment such as Gleevec...

..GISTs carrying 1530ins6 occur exclusively in the intestinal location, and a great majority of these tumors follow a malignant course...

..e., reversion of the tumor cell phenotype to that of fetal endothelial cells that may show KIT expression)...

..More cases of nonhuman primate GISTs should be analyzed to discover the clinicopathologic spectrum of GISTs in these species...

..Twenty-eight (97%) were positive for smooth muscle actin and 18 (62%) for desmin but none for CD117 and S-100. Both GISTs and true LMs occur in the GI tract of dogs. Both tumors have distinctive pathologic features...

..It is best avoided by employing a panel of leukocyte and epithelial antigens and by use of electron microscopy, if possible...

..This case illustrates that tumors phenotypically and genotypically similar to GISTs may present in sites other than the tubular gastrointestinal tract...

..The majority of splenic angiosarcomas coexpress histiocytic and endothelial markers by immunohistochemical analysis, which suggest that some tumors may originate from splenic lining cells...

..GISTs with secondary mutations in exon 13 and 14 are sensitive to sunitinib, another tyrosine kinase inhibitor. KIT and PDGFRA genotyping is important for GIST diagnosis and assessment of sensitivity to tyrosine kinase inhibitors...

..Additional analysis using CD79a, CD43, TdT, and PCR should be performed to avoid misdiagnosis. True ES is negative for lymphoid markers including CD79a, CD43, and TdT, as well as for IgH-R and Tgamma-R...

..The coexistence of NF2 gene mutations and LOH at the NF2 locus indicates that the NF2 tumor suppressor gene is altered in PNTs by the two-hit mechanism...

..Alveolar soft part sarcoma (ASPS) is a rare sarcoma in the buttocks or thigh of young adults, often with metastases to lung, brain, or bone. This study examines the morphological and clinical features of lingual ASPS...

..Recognition that the appearances of the various types of musculoskeletal fibromatoses reflect their pathologic characteristics improves radiologic assessment and helps optimize patient management...

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..However, focal expression of K1 and K7 cannot be ruled out. Keratin-positive schwannomas should not be confused with other keratin-positive tumors, such as sarcomatoid carcinoma, mesothelioma, and synovial sarcoma...

..However, lack of NF2 alterations strongly supports the hypothesis that GI schwannomas represent a morphologically and genetically distinct group of peripheral nerve sheath tumors that are different from conventional schwannomas...

..The cross-sectional imaging appearance is that of a well-defined mural mass that may have an exophytic component and may invade adjacent structures. A prominent intraluminal component is a rare feature...

..These tumors should be recognized as part of the spectrum of synovial sarcomas...

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..Although the radiologic features of GISTs are often distinct from those of epithelial tumors, criteria to separate GISTs radiologically from other nonepithelial tumors have not yet been fully developed...

..Mutation genotyping is a tool in GIST diagnosis and in assessment of sensitivity to kinase inhibitors. This is a US government work. There are no restrictions on its use...

..To comprehensively capture all GISTs, KIT immunostains should be performed on all unclassified epithelioid and mesenchymal tumors of the abdomen. This is a US government work. There are no restrictions on its use...

..Use of the PCR assay amplifying the specific region affected by duplications and yielding 129 bp in wild-type KIT can substantially improve the detection of these mutations in formalin-fixed, paraffin-embedded GISTs...

..5%, based on evaluation of 700 KIT exon 11 mutants. Molecular events leading to formation of deletion-inversions remain elusive and should be studied further...

..An origin from fibroblastic cells with the ability to differentiate into myofibroblasts and a tendency to recruit histiocytic cells is postulated...

..4 months. Based on these findings, we conclude that presence of homozygous KIT exon 11 mutations is associated with malignant course of disease and should be considered an adverse prognostic marker in GISTs...

..The latter is also true for all KIT exon 17 mutant GISTs...

..Moreover, KIT codon 558 insertions might indicate an increased risk of malignant behavior for gastric gastrointestinal stromal tumors...

..We also suggest that these polyps may develop from earlier described PDGFRA-positive mesenchymal cells distributed along the villus membrane after oncogenic PDGFRA activation...

..These tumors have a relatively high local recurrence rate when managed by simple local excision. They appear to be unrelated to so-called cellular and mixed-type neurothekeomas...

..In four cases with moderate or high malignant potential GISTs, a long-term follow-up (average 235.5 months) showed favorable course of disease...

..This suggests that presence of these IDTs may define a clinicopathologically favorable subset of GISTs. The consequence of these mutations to KIT signaling should be investigated...

..Optimal management appears to be complete local excision with periodic follow-up visits to monitor for local recurrence...

..Recurrences developed in 85 (45%) patients. Overall, T1 glottic tumors managed by complete surgical eradication had the best outcome (mean follow-up, 7.8 years)...

..The differential diagnosis includes conventional mixed tumors of skin adnexal or salivary gland origin, synovial sarcoma, a peripheral nerve sheath tumor variant, and cystic teratoma...

..Superficial leiomyosarcomas of the penis are optimally managed by wide local excision whenever this is technically feasible. Tumors with a deep-seated component may require more aggressive intervention to ensure complete removal...

..The cross-sectional imaging appearance of gastrointestinal stromal tumors that occur in patients with neurofibromatosis is similar to that of gastrointestinal stromal tumors that occur in the general population...

..Based on long-term follow-up (average 135 months), a majority (83.5%) of GISTs with PDGFRA mutations followed a benign course...

..Interpreting abdominal imaging studies in patients with NF1 can be challenging because of the wide spectrum and diverse nature of tumors that occur in this disease...

..An isolated LOH at D22S425 was equally found in both benign and malignant tumors. These observations may suggest that LOHs on chromosome 22q in GISTs play a role in early stages of tumor formation as well as in late tumor progression...

..Thirty-two of 38 patients (84.2%) with clinical follow-up, ranging from 4 months to 33 years (mean, 14 years 9 months; median, 16 years 1 month), had one (n = 16) or more (n = 16) local recurrence of their fibromatosis...

..Colorectal schwannomas behaved in a benign fashion with no evidence of aggressive behavior or connection with neurofibromatosis 1 or 2, based on follow-up information on 18 patients...

..p75 may be useful to distinguish DFSP from benign fibrous histiocytoma...

..It is a benign tumor that does not recur with complete excision. Hibernomas should not be confused with atypical lipomas or well-differentiated liposarcoma...

..They are homogeneously attenuating, well-defined, mural masses on CT. The lack of low-attenuation hemorrhage, necrosis, and degeneration within the tumor may help distinguish these tumors from gastrointestinal stromal tumors on CT...

..3 years), whereas 40 patients are either alive or had died of unrelated causes (mean 13.9 years). A TNM-type classification separated by anatomic site of involvement and metastatic disease is proposed to predict biologic behavior...

..Careful histologic analysis is necessary to differentiate anaplastic meningiomas and metastatic carcinomas, which have overlapping patterns of several keratins except K20, which was never present in any type of meningioma...

..CD163 appears to be a specific histiocytic marker and is important in establishing the diagnosis of HS...

..We conclude that survival beyond 3 years is possible for primary pulmonary artery sarcoma, but cure without evidence of disease is currently possible only for the select subtype of intravascular low-grade myofibroblastic sarcoma...

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..Antibodies to certain keratin subunits and other novel antigens now available to surgical pathologists have not been tested on a large number of cases...

..Recognition of PMTMCT is critical, as complete resection cures intractable OO. Immunohistochemistry and RT-PCR for FGF-23 confirm the role of this protein in PMTMCT-associated OO...

..To determine the prognostic relevance of p16INK4 alterations in GISTs, we investigated a larger group of GISTs and correlated the genetic findings with clinicopathological factors and patient survival...

..This finding may relate to the observed poor prognostic outcome in this type of sarcoma. Also unique to our case is the translocation involving 7q and 9p, both regions may play a role in MPNST...

..P16 loss is a common molecular abnormality in GISTs and might be used in routine diagnosis to identify patients with high-risk tumors...

..The potential presence of K8 and K18 in GISTs should not lead to the misdiagnosis of carcinoma on biopsy...

..The occurrence of this tumor in an HIV-positive patient is coincidental, and it resulted in an extremely unusual metastatic site that has not been reported for GISTs...

..Consequently, the presence of epithelioid cells in certain malignant noncarcinomatous neoplasms raises speculation that the expression of ECAD and NCAD in these neoplasms may have diagnostic significance...

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..The potential nonrandom association and causal relationship between GIST and other neoplasms remain to be investigated...

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..Accurate subclassification of some of these lesions is difficult based on currently available techniques...

..KIT and PDGFRA wild type was found in 15% of cases. Analysis of KIT and PDGFRA mutations is of significance for treatment with tyrosine kinase inhibitors, and may also have value when assessing the biological potential of GIST...