A rapidly developing lung mass diagnosed as desmoplastic small round cell tumor

Mediastinal desmoplastic small round cell tumor

RATIONALE

Desmoplastic small round cell tumor (DSRCT) is a rare distinct tumor with a high-grade malignancy.

PATIENT CONCERNS

A 51-year-old male visited a local hospital in April 2016 complaining of shortness of breath, chest tightness and pain, and exhibited significant swelling in both sides of the chest.

DIAGNOSES

CT demonstrated thoracic symmetry and no abnormalities were observed in the soft tissues of the ribs and the chest wall. A general observation of CT-guided puncture biopsy revealed 2 stripes of gray and grayish-white puncture tissues of 0.5 and 1 cm in length, respectively, and 0.1 cm in diameter. These results preliminarily suggested a (mediastinum) malignant small round cell tumor.

INTERVENTION

Given the progression of the disease, the chemotherapy regimen, consisting of ifosfamide and etoposide, was altered during the course and radiotherapy (total of 70 Gy of mediastinal Y field radiation) was conducted.

OUTCOMES

The patient and his family declined further treatment. Through follow-up, the total survival period was determined as 17 months.

LESSONS

DSRCT is a rare interstitial malignant tumor. Effective cytoreduction combined with comprehensive therapies could achieve partial remission or prolong the survival of patients.

Construction of diagnosis system and gene regulatory networks based on microarray analysis

A microarray analysis generally contains expression data of thousands of genes, but most of them are irrelevant to the disease of interest, making analyzing the genes concerning specific diseases complicated. Therefore, filtering out a few essential genes as well as their regulatory networks is critical, and a disease can be easily diagnosed just depending on the expression profiles of a few critical genes. In this study, a target gene screening (TGS) system, which is a microarray-based information system that integrates F-statistics, pattern recognition matching, a two-layer K-means classifier, a Parameter Detection Genetic Algorithm (PDGA), a genetic-based gene selector (GBG selector) and the association rule, was developed to screen out a small subset of genes that can discriminate malignant stages of cancers. During the first stage, F-statistic, pattern recognition matching, and a two-layer K-means classifier were applied in the system to filter out the 20 critical genes most relevant to ovarian cancer from 9600 genes, and the PDGA was used to decide the fittest values of the parameters for these critical genes. Among the 20 critical genes, 15 are associated with cancer progression. In the second stage, we further employed a GBG selector and the association rule to screen out seven target gene sets, each with only four to six genes, and each of which can precisely identify the malignancy stage of ovarian cancer based on their expression profiles. We further deduced the gene regulatory networks of the 20 critical genes by applying the Pearson correlation coefficient to evaluate the correlationship between the expression of each gene at the same stages and at different stages. Correlationships between gene pairs were calculated, and then, three regulatory networks were deduced. Their correlationships were further confirmed by the Ingenuity pathway analysis. The prognostic significances of the genes identified via regulatory networks were examined using online tools, and most represented biomarker candidates. In summary, our proposed system provides a new strategy to identify critical genes or biomarkers, as well as their regulatory networks, from microarray data.

A Biphasic Pleural Tumor with Features of an Epithelioid and Small Cell Mesothelioma: Morphologic and Molecular Findings

Malignant mesotheliomas are generally classified into epithelioid, sarcomatoid, desmoplastic, and biphasic types with rare reports of a small cell form. These small cell variants display some morphologic overlap with desmoplastic small round cell tumors (DSRCTs) which generally occur within the abdominal cavity of young males and are defined by a characteristic t(11;22)(p13;q12) translocation. However, there are rare reports of DSRCTs lacking this translocation. We present a 78-year-old man with a pleura-based biphasic neoplasm with features of both epithelioid mesothelioma and a small cell blastema-like neoplasm. The epithelioid portion showed IHC reactivity for pan cytokeratin, CK5/6, D2-40, and calretinin and the small cell portion marked with CD99, pan cytokeratin, WT1, FLI1, S100, CD200, MyoD1, and CD15. Fluorescence in situ hybridization testing for the t(11;22)(p13;q12) translocation disclosed loss of the EWSR1 gene in 94% of tumor cell nuclei, but there was no evidence of the classic translocation. Array based-comparative genomic hybridization (a-CGH) confirmed the tumor had numerous chromosome copy number losses, including 11p15.5-p11.12 and 22q12.1-q13.33, with loss of the EWSR1 and WT1 gene regions. Herein, we report novel complex CGH findings in a biphasic tumor and review the molecular genetic alterations in both mesothelioma and DSRCTs.

Primary Synovial Sarcoma of Lung: A Rare Tumor

Synovial sarcoma of lung is a rare tumor with few case reports in literature. Though named synovial sarcoma due to its resemblance to synovium on light microscopy, it arises from mesenchymal tissue. Here, we present a case of synovial sarcoma of lung in a 7-year old boy, with main emphasis on difficulty faced in the management.

Primary synovial sarcoma of lung

A synovial sarcoma (SS) is a rare form of cancer which usually occurs near the joints of the arm, neck, or leg, but has been documented in most human tissues and organs, including the brain, prostate, and heart. Primary pulmonary SS is an extremely rare tumor. We report a case of primary SS of lung who presented with severe chest pain and a large right lung mass with right-sided pleural effusion in computed tomography (CT) scan of thorax. The diagnosis was made on the basis of CT-guided core biopsy and immunohistochemistry. On immunohistochemistry, tumor cell expressed epithelial membrane antigen, bcl 2, Vimentin and smooth muscle actin and were immunonegative for S100 and cytokeratin. So, the final diagnosis was primary SS.

Primary monophasic synovial sarcoma lung with brain metastasis diagnosed on transthoracic FNAC: Report of a case with literature review

Synovial sarcoma is highly malignant tumor of soft tissues, occurring chiefly in the extremities and limb girdle with a propensity for local recurrence and sometimes metastases to the lungs. Primary synovial sarcoma arising in the lungs is rare and brain metastasis as presentation is further uncommon. We report a case of primary monophasic synovial sarcoma lung presenting with brain metastasis in a 35-year-old male patient. The diagnosis was made on percutaneous transthoracic needle aspiration from left-sided pulmonary mass and later confirmed by immunohistochemistry. The utility of preoperative diagnosis by percutaneous aspiration cytology is also stressed.