Diagnostic gold standard for soft tissue tumours: morphology or molecular genetics?

Consistency evaluation of lung adenocarcinoma tissue and circulating tumor cells related gene mutation detection based on multi-site immunomagnetic beads

This study was designed to investigate the feasibility of genetic testing using circulating tumor cells (CTCs) instead of tumor tissues in lung adenocarcinoma to break through its limitation. Separation system for epithelial cell adhesion molecule (EpCAM), epidermal growth factor receptor (EGFR), and Vimentin expressing CTCs was constructed and used to capture CTCs in the blood samples of 57 patients with lung adenocarcinoma. Genetic mutations of genes involved in targeted therapies were detected by next-generation sequencing (NGS) in tissues from these patients. Blood CTC samples with the gene mutations identified by tissue-NGS were selected and corresponding gene mutations were detected by Sanger sequencing. The specificity of the CTC separation system was 95.48% and the sensitivity was 90.85%. The average number of CTCs in the blood of patients with lung adenocarcinoma was 12.47/7.5 mL. Comparison of the tissue-NGS with the CTC-Sanger sequencing showed that the consistencies of genetic mutations of EGFR (n = 24), KRAS (n = 9), TP53 (n = 19), BRAF (n = 1), ERBB2 (n = 2), and PIK3CA (n = 3) were 92.31%, 75.00%, 86.36%, 50.00%, 66.67%, and 75.00%, with an overall consistency of 84.06%. The CTC separation system established in this study shows high specificity and sensitivity. CTCs can be used as a suitable alternative to tumor tissues that are difficult to obtain in clinical practice and overcome the difficulties in tumor tissue collection, which is of significance in guiding clinical medication and individualized treatment with significant clinical application value in terms of genetic testing for targeted therapies in tumor treatment.

Large inguinal synovial sarcoma mimics a vascular lesion: A case report and literature review

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Synovial sarcomas mostly affect adolescents and young adults with slight male predominance.

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The cellular origin of SS is disordered mesenchymal stem cells that have undergone self-renewal dysregulation mediated by the SS18-SSX fusion protein.

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Novel therapies targeting molecular and genetic pathways of SS are under research, including SYT-SSX-derived peptide vaccine, retinoic acid and its derivatives.

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Various manifestations and rarity of SS could mimic vascular lesion which mislead the diagnosis.

Introduction

Synovial sarcoma (SS) is one of soft tissue sarcomas (STS), characterized by t(X;18)(p11;q11) chromosomal translocation. Clinical diagnosis of SS in groin is difficult owing to rarity and various manifestations. We reported a rare and interesting case of inguinal biphasic SS with initial impression of a vascular lesion.

Presentation of case

We reported a 72-year-old man who presented with a right inguinal progressively enlarged mass for 5 years. The mass became ulcerative with active bleeding after blunt trauma. Computed tomography (CT) showed a large heterogeneous tumor with focal vivid enhanced area, and an inguinal vascular lesion was impressed. Angiography revealed faint tumor stain without contrast extravasation or aneurysm lesion. Surgical resection of the tumor was performed. Final pathology and fluorescence in situ examination (FISH) demonstrated biphasic SS with SS18 gene rearrangement. No evidence of recurrence after one-year follow-up.

Discussion

SS constitutes 5%–10% of STS. The most primary sites are extremities (68.7%) and trunk (15.7%). Treatment options for SS include surgery, chemotherapy, radiotherapy, targeted therapy, and novel therapies. In our case, the initial impressions of large inguinal tumor were hematoma or pseudoaneurysm. Preoperative angiography assisted in differentiating the lesion, evaluating tumor vessels, and preventing bleeding by embolization. Our patient recovered satisfactorily after surgical excision without major complications.

Conclusion

Primary inguinal SS is an extremely rare tumor which can present as a vascular lesion. Diagnosis is confirmed by pathology and FISH exam. Further studies are required to determine the manifestation and management of SS.

A review on immunohistochemical and histopathologic validation in PET-CT findings with consideration to microRNAs

Purpose

This review provides an overview of some of the most recent clinical trials which investigated various types of cancer and other diseases, through the use of PET-CT imaging, highlighting the use of immunohistochemical stains or conventional histopathology for the validation or contradiction of their hypothesis. Furthermore, we investigate a potential new direction of research by analyzing the upcoming role of microRNAs in disease confirmation.

Methods

An extensive search of MEDLINE/PubMed and SCOPUS electronic databases was made, using the MeSH terms "positron emission tomography computed tomography" and "immunohistochemistry" as well as "SUV" and "immunohistochemistry", restricting the search by clinical trials and time period. Further searches were made for articles regarding Ki-67 and microRNAs in correlation with metabolic PET-CT uptake.

Results

Out of all 389 initial search results, 27 original articles were found relevant to the topic. Their contents were synthesized and discussed regarding the matter at hand. No relevant clinical trials involving microRNAs were found.

Conclusions

Immunohistochemical and histopathologic results remain widely used and indispensable in modern research, concerning PET-CT validation. Possible candidates for diagnosis confirmation, in future research, may reside in the further development of microRNAs.

GEFT aberrant expression in soft tissue sarcomas

Background

Guanine nucleotide exchange factor T (GEFT) exhibits high amplification level using high-resolution array comparative genomic hybridization in rhabdomyosarcoma. The overexpression rate of GEFT protein is higher in rhabdomyosarcoma than in normal striated muscle tissues. This study evaluated the aberrant expression of GEFT in multiple subtypes of soft tissue sarcoma (STS) and compared the differences in clinical pathology, histological feature and expression levels of GEFT protein and mRNA between chromosomal translocation-associated sarcomas (CTAS) and non-chromosomal translocation-associated sarcomas (NCTAS).

Methods

GEFT protein expression was detected using immunohistochemistry (IHC) and tissue microarrays. Quantitative reverse transcriptase polymerase chain reaction (qRT-PCR) was used to detect the expression of GEFT mRNA.

Results

The rates of GEFT positive expression (196/219, 89.50%) and overexpression (113/219, 51.60%) were higher in multiple subtypes of STS than in normal striated muscle tissues. The rates of GEFT positive expression and overexpression in all subtypes of STS detected were significantly higher than that in the controls. No difference of GEFT expression was detected between CTAS and NCTAS.

Conclusions

The abnormal expression of GEFT exists in various subtypes of STS, which may play an important role in tumorigenesis of STS.

Pulmonary adenofibroma: cytologic and clinicopathologic features of a rare benign primary lung lesion

We report a case of pulmonary adenofibroma in a 29-year-old female found by CT scan during work-up for midline chest pain. To our knowledge, the cytological features of this entity have not been previously reported. Cytology demonstrated bland epithelial and stromal cells of varying size without karyorrhexis, pyknosis, or necrosis and with very rare mitoses. Stromal cells were present as either naked bipolar nuclei, as spindle cells with fragile eosinophilic cytoplasm, or as rare larger carrot shaped nuclei. Epithelial cells were present as small loosely cohesive groups with smooth round nuclei and moderate amounts of cytoplasm. Histologically, this lesion consisted of a leaf-like fibroepithelial pattern in which the clefts were lined by a single layer of cuboidal epithelium reminiscent of adenofibroma occurring in the female genital tract. Immunohistochemical analysis demonstrated epithelium that stained positively for pan-cytokeratin and TTF-1. The stroma stained positively for vimentin and desmin, and was weakly positive for SMA-1. The lesion was confirmed to be pulmonary adenofibroma with a smooth muscle component. The differential diagnosis for this lesion includes, but is not limited to, pulmonary hamartoma, pulmonary blastoma, adenomyofibroma, synovial sarcoma, and visceral metastases. It is important for cytopathologists to be aware of this benign entity because it can be encountered on lung FNA specimens. Considering this benign lesion in the differential diagnosis may help plan for minimal lung resection. Confirmatory intraoperative frozen section is a reasonable option.

Synovial sarcoma arising in the foot: case report

Synovial sarcomas occur primarily in the soft tissue structures adjacent to the joints and tendons of the extremities. A diagnostic dilemma exists when the clinical presentation is similar to that of an infection or soft tissue trauma. We report a case of soft tissue sarcoma of the foot in a previously healthy 19-year-old male who presented after hitting his right foot against a refrigerator. Initial radiographs were negative; however, 6 weeks later plain radiographs revealed destruction of the metatarsals. Histologic analysis on a specimen obtained via fine-needle aspiration confirmed the diagnosis of primary synovial sarcoma. Further workup revealed metastases to the lungs. An amputation at Chopart's joint was performed. Primary synovial sarcoma in the foot can mimic infection or edema from a traumatic event. Clinicians should always be suspicious of soft tissue masses and keep neoplastic processes in the list of differentials.

Malignant inguinal monophasic synovial sarcoma: report of a case and review of the literature

Background

A synovial sarcoma (SS) is an aggressive soft tissue tumor that classically occurs in the extremities near, but rarely within large joints, in young adults. Variable symptoms and clinical manifestations may be encountered and a definite diagnosis should depend on pathological results. This poses certain difficulties in arriving at a prompt diagnosis and appropriate treatment.

Case presentation

We report the case of a 68-year-old woman patient who presented an inguinal mass with swelling and pain in the right lower limb. She underwent surgery, and later received systematic intravenous chemotherapy. The pathological studies, especially the specific chromosomal translocation of a t(X;18) (p11.2;q11.2), confirmed the diagnosis as a synovial sarcoma. To the best of our knowledge, this is the first report of a monophasic synovial sarcoma in the inguinal region.

Conclusion

Besides making the readership aware of the rarity of location and age of this present case, this report distinctly highlights the great value of a molecular analysis of an SYT associated genetic alteration in the diagnosis of synovial sarcoma occurring at rare sites especially when immunochemical results are equivocal.

SYT-SSX fusion is absent in sarcomatoid mesothelioma allowing its distinction from synovial sarcoma of the pleura

The diagnosis of sarcomatoid mesothelioma is still a worldwide challenge and it is often difficult, both clinically and by morphological analysis, to differentiate sarcomatoid mesothelioma from synovial sarcoma, the most frequent intrathoracic sarcoma. To confirm the absence of the synovial sarcoma translocation t(X; 18) (SYT-SSX) in sarcomatoid mesothelioma, and to test its usefulness differentiating sarcomatoid mesothelioma from synovial sarcoma, 28 tumours were examined using the reverse transcriptase-polymerase chain reaction. RNA was extracted from paraffin blocks using standard methods, reverse-transcribed and PCR performed. Molecular analysis completed in two independent laboratories showed that sarcomatoid mesothelioma samples were negative for the t(X-18). This result confirms the usefulness of this analysis in differentiating sarcomatoid mesothelioma from synovial sarcoma.

Immunoprofiles in malignant peripheral nerve sheath tumor: three case reports and literature review

Because there are no standardized radiologic and histologic criteria, the differential diagnosis of malignant peripheral nerve sheath tumors (MPNSTs) from other spindle cell neoplasms poses great challenges for pathologists. Because early diagnosis of MPNSTs arising from benign peripheral nerve sheath tumors (BPNSTs) means a better prognosis, many immunohistochemical and molecular studies have recently emerged. Nevertheless, no gold standard diagnostic criterion is to be found in the literature. For example, S-100 protein is widely used in the diagnosis of MPNST. Other promising ancillary markers are p53 and Ki-67; however, the staining patterns and possible mechanisms of these markers are seldom mentioned in the literature. These evoke our interest. Only six cases diagnosed as MPNST were retrieved from the archives of the Department of Pathology, Kaohsiung Medical University Chung-Ho Memorial Hospital between 1988 and September 2005. Clinical files were available for three of them, and we found nuances in the immunohistochemistry from these previous reports. Here, we present these rare sarcomas and review the literature.

Association of argyrophilic nucleolar organizing regions, Ki-67, and proliferating cell nuclear antigen scores with histologic grade and survival in dogs with soft tissue sarcomas: 60 cases (1996—2002)

OBJECTIVE

To determine whether argyrophilic nucleolar organizing regions (AgNORs), Ki-67, and proliferating cell nuclear antigen (PCNA) scores were associated with histologic grade and survival in dogs with soft tissue sarcomas (STSs).

DESIGN

Retrospective study.

ANIMALS

60 dogs with STSs.

PROCEDURE

Medical records were examined and histologic specimens were reviewed. Tissue specimens obtained from archival materials were used to prepare sections for histologic staining for AgNOR and immunohistochemical staining for Ki-67 and PCNA labeling. Follow-up monitoring was obtained by reevaluation or telephone conversations with referring veterinarians or owners.

RESULTS

27 (45%) STSs were grade 1, 23 (38%) were grade 2, and 10 (17%) were grade 3. The mean and median AgNOR, Ki-67, and PCNA scores were determined, and significant positive associations among AgNOR and Ki-67 scores with histologic grade and mitotic score were detected. Fifty-four dogs had adequate follow-up examinations and were included in survival analysis and evaluation of prognostic factors. Overall median survival time was > 1,306 days. Twelve of 54 (22%) dogs died of tumor-related causes. Metastatic disease developed in 8 of 54 (15%) dogs. Results of univariate analysis indicated that increased mitotic score, increased AgNOR score, increased Ki-67 score, incomplete surgical margins, noncurative intent surgery, Ki-67 score greater than the median Ki-67 score, and AgNOR score greater than the median AgNOR score were prognostic factors for decreased survival time. Results of multivariate analysis indicated that increased AgNOR score was the only prognostic factor for decreased survival time.

CONCLUSIONS AND CLINICAL RELEVANCE

Results suggested that AgNORs and possibly Ki-67 should be routinely evaluated with histologic grading for STSs in dogs.

The role of genetic testing in soft tissue sarcoma

Soft tissue tumours represent a heterogeneous group of mesenchymal lesions and their classification continues to evolve as a result of incorporating advances in cytogenetic and molecular techniques. In the last decade traditional diagnostic approaches were supplemented with a significant number of reliable molecular diagnostic tools, detecting tumour type-specific genetic alterations. In addition, the successful application of some of these techniques to formalin-fixed paraffin-embedded tissue made it possible to subject a broader range of clinical material to molecular analysis. Thus, molecular genetics has already become an integral part of the work-up in some tumours, such as paediatric small blue round cell tumours, which demonstrate characteristic translocations. Several lines of evidence suggest that sarcomas can be divided into two major genetic groups: (i) sarcomas with specific genetic alterations and usually simple karyotypes, such as reciprocal chromosomal translocations (e.g. FUS-DDIT3 in myxoid liposarcoma) and specific oncogenic mutations (e.g. KIT mutation in gastrointestinal stromal tumours); and (i) sarcomas with non-specific genetic alterations and complex unbalanced karyotypes. Some of these genetic abnormalities, including chromosomal numerical changes, translocations, gene amplifications or large deletions can be apparent at the cytogenetic level (karyotyping, fluorescence in situ hybridization), while others, such as small deletions, insertions or point mutations, require molecular genetic techniques (polymerase chain reaction and sequence analysis). This review focuses on the applicability of genetic testing in the diagnosis and prognosis of soft tissue sarcomas, and gives a realistic appraisal of the ancillary role of molecular techniques, including its advantages and limitations.

Association of the t(12;22)(q13;q12) EWS/ATF1 rearrangement with polyphenotypic round cell sarcoma of bone: a case report

The t(12;22)(q13;q12) chromosomal rearrangement results in an EWS/ATF1 fusion transcript and is associated with clear cell sarcoma (CCS). CCS is an uncommon tumor arising in tendons and aponeuroses of the extremities and shows evidence of melanocytic differentiation at the light microscopic, immunohistochemical, and/or ultrastructural level. Only 5 cases have been reported to arise in bone, none of which had molecular confirmation of the diagnosis. The current report describes a 7-year-old girl with a primary round cell sarcoma of the left humerus showing polyphenotypic differentiation on immunohistochemical analysis. Antibodies directed at melanocytic antigens were negative, and there was no evidence of melanocytic differentiation by light microscopy or ultrastructural analysis. Cytogenetic analysis revealed rearrangement of the EWS locus within 22q12. RT-PCR and sequence analysis revealed the presence of a fusion transcript bringing together exon 7 of EWS with exon 5 of ATF1, consistent with a type 2 transcript reported in association with CCS. However, given the lack of morphologic features usually present in CCS, a diagnosis of polyphenotypic round cell sarcoma was made. This tumor thus expands the spectrum of neoplasms associated with the t(12;22)(q13;q12) rearrangement.

Molecular genetics of pediatric soft tissue tumors: clinical application

The application of molecular genetics to pediatric soft tissue tumors has grown tremendously over the last decade. It has resulted in the identification of novel genes that have provided us with an increased understanding of oncogenesis. Furthermore, these findings have identified diagnostic and potentially prognostic factors for patient management. Molecular diagnostic techniques, such as reverse transcription PCR (RT-PCR) and fluorescence in situ hybridization (FISH), have become important tools for evaluating pediatric soft tissue tumors. By detecting characteristic fusion genes, these techniques have greatly increased the diagnostic accuracy of histopathological classification. One of the exciting promises of the development of these molecular techniques is their ability to detect micrometastasis and minimal residual disease. Monitoring of minimal residual disease in pediatric soft tissue tumors by quantitative RT-PCR may provide important prognostic information. Furthermore, the potential development of targeted therapy based on the understanding of the molecular pathology of a specific soft tissue tumor may complement existing treatments and improve disease outcome.

Practical application of molecular genetic testing as an aid to the surgical pathologic diagnosis of sarcomas: a prospective study

The strong correlation of specific reciprocal translocations with individual tumor types and the demonstration that polymerase chain reaction (PCR)-based methods can detect translocations in tissue samples have stimulated interest in the role of molecular genetic testing in diagnostic surgical pathology. To evaluate the clinical utility of PCR-based molecular analysis of soft tissue neoplasms in routine surgical pathology, 131 consecutive soft tissue tumors submitted for molecular genetic testing at a tertiary care teaching hospital were prospectively analyzed over a 36-month period. RT-PCR was used to test tumor RNA for fusion transcripts characteristic of malignant round cell tumors (including Ewing sarcoma/primitive neuroectodermal tumor, desmoplastic small round cell tumor, and alveolar rhabdomyosarcoma), spindle cell tumors (including synovial sarcoma and congenital fibrosarcoma), and fatty tumors (myxoid liposarcoma). DNA sequence analysis was used to confirm the identity of all PCR products, and the PCR results were compared with the histopathologic diagnosis. We found that sufficient RNA for RT-PCR-based testing was recovered from 96% of the 131 cases and the percentage of tumors that tested positive for the associated characteristic fusion transcript was in general agreement with those reported in the literature. DNA sequence analysis of PCR products identified both variant transcripts and spurious PCR products, underscoring the value of product confirmation steps when testing formalin-fixed, paraffin-embedded tissue. Only in rare cases did testing yield a genetic result that was discordant with the histopathologic diagnosis. We conclude that PCR-based testing is a useful adjunct for the diagnosis of malignant small round cell tumors, spindle cell tumors, and other miscellaneous neoplasms in routine surgical pathology practice.

Soft-tissue sarcoma in childhood and adolescence

This review summarizes and comments on the major articles that have been published in English concerning pediatric soft-tissue sarcomas in the past 2 years. Studies of rhabdomyosarcoma and undifferentiated sarcoma, including late sequelae of treatment; nonrhabdomyosarcomatous soft-tissue sarcoma; and the pathology of soft-tissue sarcomas are included.

Malignant peripheral nerve sheath tumors are t(X;18)-negative sarcomas. Molecular analysis of 25 cases occurring in neurofibromatosis type 1 patients, using two different RT-PCR-based methods of detection

To verify the absence of the synovial sarcoma translocation t(X;18) (SYT-SSX) in malignant peripheral nerve sheath tumors, 34 tumor samples from 25 neurofibromatosis type 1 patients were examined in two independent laboratories (Bordeaux, France, and Lausanne, Switzerland) using reverse transcriptase polymerase chain reaction (RT-PCR)-based techniques. RNA was extracted from paraffin blocks using standard methods, reverse transcribed, and conventional (in one laboratory) versus real-time (in the other laboratory) PCR performed. Twenty-seven tumor samples from 19 patients were negative for the t(X;18) in both laboratories; six additional tumors that were t(X;18)-negative in one laboratory gave noninterpretable results in the other, due to lack of internal positive controls; one case was noninterpretable in both places. In conclusion, malignant peripheral nerve sheath tumors in neurofibromatosis type 1 patients do not bear the synovial sarcoma t(X;18) (SYT-SSX). Laboratories that use PCR-based techniques for diagnostic purposes would benefit from quality assurance programs.

Lack of SYT-SSX fusion transcripts in malignant peripheral nerve sheath tumors on RT-PCR analysis of 34 archival cases

The translocation t(X;18) is currently regarded as a specific molecular marker of synovial sarcoma (SS). Recently, however, it has been reported that malignant peripheral nerve sheath tumors expressed this marker in 75% of the cases. To test independently this iconoclastic claim, a molecular analysis for the detection of the SYT-SSX fusion genes was carried out using archival material of 34 consecutive cases diagnosed as malignant peripheral nerve sheath tumors and treated in our Institute from 1998 to 2000. In four of these cases, the molecular analysis on fixed tissues was supplemented with an analysis on fresh frozen tissue. RNA extracted from formalin-fixed paraffin-embedded tissue blocks was evaluated for the presence of SYT-SSX1 and SYT-SSX2 fusion transcripts by RT-PCR. This analysis was extended to a wide variety of normal tissues simultaneously extracted and equally processed. Only two of the cases studied harbored SYT-SSX1 and SYT-SSX2 fusion transcripts, respectively. The diagnostic reevaluation of these two cases in light of the molecular data disclosed that one had the features of a monophasic SS and the other was compatible with that entity. Both of these tumors were strongly immunoreactive for bcl-2, confirming the diagnostic utility of this marker in this instance. Our results reaffirm the specificity of SYT-SSX for SS and suggest that an opposite claim made in a recent study may have been due to a faulty interpretation of the molecular results caused by a contamination of the samples.