Immunohistochemical detection of the Wilms' tumour gene WT1 in desmoplastic small round cell tumour

The desmoplastic small round cell tumour (DSRCT) is a rare, highly malignant neoplasm usually presenting in the abdomen of adolescent males. A characteristic translocation between the Ewing's sarcoma gene on chromosome 22 and the Wilms' tumour gene WT1 on chromosome 11 has been described, producing a fusion gene with expression of the DNA binding area of WT1. Some Wilms' tumour antibodies recognize epitopes of this part of the WT1 protein. All four cases of DSRCT examined showed strong staining of the tumours with an anti-WT1 antibody, suggesting this may be useful in the diagnosis of these tumours.     

Desmoplastic round cell tumor of childhood: Can cytology with immunocytochemistry serve as an alternative for tissue diagnosis?

There are limited reports on the cytology of desmoplastic small round cell tumors (DSRCT). Fine needle aspiration biopsy (FNAB) findings in seven aspirates from four cases of histologically and immunohistochemically confirmed cases were analyzed with the main intention of ascertaining if cytological diagnosis of DSRCT is possible. Also assessed were the immunocytochemistry(ICC) findings in these cases. The basic cytological impression was that of a cohesive small round cell tumor. Nuclei showed granular chromatin with grooves, nuclear molding and inconspicuous nucleoli. Stromal fragments were noted in all four cases. In two cases, awareness of cytological features in the appropriate clinical context led to a suggestion of the diagnosis of DSRCT on cytology itself. ICC on destained smears showed positivity for cytokeratin, epithelial membrane antigen (EMA), desmin and WT-1 in two cases. In conclusion, given the right clinical setting, a cytological diagnosis of DSRCT is plausible and in conjunction with ICC may help in documenting the polyphenotypic nature and thereby confirming the diagnosis.     

Desmoplastic small round cell tumor of the central nervous system: report of two cases and review of the literature

Desmoplastic small round cell tumor (DSRCT) is a malignant tumor often involving the abdominal and/or pelvic peritoneum. Only one fully documented example has arisen in the central nervous system (CNS). Herein, we describe two additional examples, fulfilling the morphologic, immunohistochemical, and molecular criteria (EWS/WT1 translocation) of DSRCT. Both arose in the cerebellopontine angle (CPA) and underwent spinal dissemination. Patient 1, a 37-year-old male, underwent a subtotal resection, and 2 years later died of recurrent disease with spinal dissemination. Patient 2, a 39-year-old man, presented with cerebellar and CPA lesions as well as spinal leptomeningeal deposits. After 27 months of adjuvant therapy, he is alive with progressive disease. In conclusion, CNS DSRCT follows a similar aggressive course as do peritoneal examples. Although rare, DSRCT warrants consideration in the differential diagnosis of “malignant small blue cell tumors” of the CNS. For consideration of publication in Virchows Archiv.     

Desmoplastic small round cell tumor: using FISH as an ancillary technique to support cytologic diagnosis in an unusual case

Desmoplastic small round cell tumor is a rare and aggressive neoplasm that predominantly affects young males. In almost all cases, a reciprocal translocation is present resulting in the fusion of the Ewing sarcoma gene with the Wilms' tumor gene. Here we describe an unusual case occurring in a 59-year-old male, in which fluorescence in situ hybridization (FISH) was used in conjunction with immunohistochemical studies to confirm the diagnosis. To our knowledge, this is the first reported case of using FISH as an ancillary technique to confirm the cytologic diagnosis of this tumor.     

Desmoplastic small round cell tumor with sphere‐like clusters mimicking adenocarcinoma

Desmoplastic small round cell tumor (DSRCT) is a rare and aggressive neoplasm that predominantly affects young men. DSRCT often presents as multiple nodules on the serosal surface and is histologically categorized as a small round cell tumor. However, the cytological spectrum of DSRCT is not fully understood because of its rarity. Here, we report an unusual case of DSRCT that showed spheres of cells without stromal cores in pleural fluid cytology material, a finding that is typically associated with metastatic adenocarcinoma and mesothelioma. The specimen from a simultaneous needle biopsy showed the classic histology of DSRCT, comprising nests of small round cells set in desmoplasia. The diagnosis of DSRCT was further supported by immunohistochemical coexpression of cytokeratin and desmin, as well as Ewing sarcoma breakpoint region 1 gene rearrangement, which was determined by fluorescence in situ hybridization. The unusual cytological finding in this case illustrates a potential pitfall of the cytological diagnosis of pleural fluid or ascites. DSRCT should not be excluded from the differential diagnosis when sphere‐like round cell clusters are observed in pleural or abdominal effusion, particularly in young male patients. Diagn. Cytopathol. 2015;43:214–217. © 2014 Wiley Periodicals, Inc.     

Peritoneal Desmoplastic Small Round Cell Tumors with Divergent Differentiation: A Review

Peritoneal desmoplastic small round cell tumors with divergent differentiation are recently described highly aggressive neoplasms with characteristic clinical, morphologic, and immunohistochemical features. This review covers 38 cases that have been reported in the literature. The average age of patients is 18.4 years, and males are affected twice as frequently as females. Tumors generally present as multiple peritoneal nodules without obvious organ involvement. Histology shows islands of small cells set in dense desmoplastic stroma. Immunohistochemical stains are usually positive for cytokeratins, epithelial membrane antigen, desmin, and vimentin. Many cases also stain for neuron-specific enolase but rarely for other neuroepithelial markers. Ultrastructural appearances range from undifferentiated small cells to larger epithelial elements. Paranuclear aggregates of intermediate filaments are characteristic. Dense-core granules and other neuroendocrine features have been described in a minority of cases. Some tumors respond to chemotherapy, but most patients die within months to a few years. The histogenesis of these tumors is uncertain.     

促纤维化小圆细胞肿瘤5例临床病理、免疫组化及电镜观察

目的：观察５例促纤维化小圆细胞肿瘤的临床病理特点,提高对此类肿瘤的认识。方法：常规组织学（ＨＥ）、免疫组化（ＡＢＣ法）和电镜技术检测结合临床资料综合分析。结果：５例中２例多次局部复发,２例在随访中,１例确诊后４个月死亡。该肿瘤组织学特点为肿瘤组织呈单结节或多结节状浸润生长,伴有明显致密的成熟纤维性间质增性,肿瘤细胞主要为大小比较一致的小圆形细胞,呈团状或巢状埋于增生纤维间质中,少数病例部分区域肿瘤     

Pathologic, cytologic and immunohistochemical findings of an intra-abdominal desmoplastic small round cell tumor in a 15-year-old male

The intra-abdominal desmoplastic small round cell tumor is a rare neoplasm. It usually occurs in young males and diffusely involves the peritoneum and pursues an aggressive clinical course. The present patient was a 15-year-old male who experienced abdominal pain and abdominal swelling. The patient was diagnosed with an intestinal myogenic sarcoma, and surgery for tumor resection was performed in June 1999. The tumor was a 20 x 15 x 15 cm well-defined mass in the peritoneum involving the transverse colon and stomach with peritoneal disseminations and splenic metastasis. Microscopic findings were well-defined nests composed of small round cells and separated by abundant desmoplastic stroma. Cytologically, the tumor cells consisted of small, round to oval cells with a scant amount of light blue cytoplasm. Immunohistochemically, the tumor cells were positive for anti-epithelial membrane antigen, vimentin, desmin, neuron-specific enolase and WT1 protein antibodies. Similar pathologic features with other small round cell tumors may lead to differential diagnostic difficulties that require the application of ancillary diagnostic methods, such as immunohistochemistry and cytogenetic techniques.     

Unusual aspects of desmoplastic small round cell tumor

Desmoplastic small round cell tumor (DSRCT) is a neoplasia that occurs mainly in childhood and involves abdominal or peritoneal sites, coexpressing ectodermal and mesenchimal immunophenotypic markers, and is endowed with an impressive stromal desmoplasia that tends to decrease on tumor relapse. To date, over 150 cases have been collected in the literature. Its presumed neuroectodermal histogenesis has been challenged by cytogenetic findings different from those usually associated with neoplasms of neuroectodermal origin. The authors report a case bearing clinical and histologic aspects of typical desmoplastic retroperitoneal small cell tumor, with intense and diffuse nuclear immunopositivity for WT1, but lacking divergent immunophenotype. Ultrastructural investigation revealed that desmoplasia could result from fibrillary synthesis by neoplastic cells.     

Intra-abdominal Desmoplastic Small Round Cell Tumor of the Peritoneum in a Young Man

The desmoplastic small round cell tumor (DSRCT) has a predilection for involvement of the peritoneal surfaces of young adult men. The tumor has an extremely poor prognosis: despite aggressive therapy the patients usually die of disease within the first 2 years following diagnosis. The present report details the pathologic features of a pelvic tumor, which proved to be a DSRCT, arising in a previously healthy 24-year-old man. The light microscopic features were typical of a DSRCT—the tumor cells were small and round, had inconspicuous cytoplasm, and were grouped into distinctive islands and cords that were dispersed in a fibrous stroma. The immunohistochemical features were likewise characteristic of DSRCT in that the tumor cells were positive for cytokeratin, vimentin, epithelial membrane antigen, and desmin. Ultrastructurally, the tumor cells were distinguished by an abundance of intercellular junctions, cytoplasmic lipid droplets, cytoplasmic intermediate filaments, and an absence of surface microvilli. Recognition of this tumor type is important in view of both its clinical features (extremely poor prognosis despite therapy) and its potential to shed some light on the nature of the family of lesions that has traditionally been classified by light microscopists as small round cell tumors.     

Intra-abdominal Desmoplastic Small Round Cell Tumor of the Peritoneum in a Young Man

The desmoplastic small round cell tumor (DSRCT) has a predilection for involvement of the peritoneal surfaces of young adult men. The tumor has an extremely poor prognosis: despite aggressive therapy the patients usually die of disease within the first 2 years following diagnosis. The present report details the pathologic features of a pelvic tumor, which proved to be a DSRCT, arising in a previously healthy 24-year-old man. The light microscopic features were typical of a DSRCT—the tumor cells were small and round, had inconspicuous cytoplasm, and were grouped into distinctive islands and cords that were dispersed in a fibrous stroma. The immunohistochemical features were likewise characteristic of DSRCT in that the tumor cells were positive for cytokeratin, vimentin, epithelial membrane antigen, and desmin. Ultrastructurally, the tumor cells were distinguished by an abundance of intercellular junctions, cytoplasmic lipid droplets, cytoplasmic intermediate filaments, and an absence of surface microvilli. Recognition of this tumor type is important in view of both its clinical features (extremely poor prognosis despite therapy) and its potential to shed some light on the nature of the family of lesions that has traditionally been classified by light microscopists as small round cell tumors.     

Desmoplastic small round cell tumor presenting as a neck mass: a case report

An unusual case study of a desmoplastic small round cell tumor presenting as a 3.5-cm, firm, supraclavicular neck mass and diagnosed by fine-needle aspirate biopsy in a 16-yr-old male is reported. Clinical, cytologic, and immunocytochemical findings are described. Histologic, immunohistochemical, and genetic features are discussed. Desmoplastic small round cell tumor should be considered in the differential diagnosis of small round cell tumors of any site; the importance of ancillary studies in arriving at the correct diagnosis is emphasized.     

促纤维组织增生性小圆细胞肿瘤2例报道及文献复习

目的 探讨促纤维组织增生性小圆细胞肿瘤的临床病理特点,提高诊断水平.方法 对2例本病少见部位发生者临床病理资料进行分析,并行组织病理学(HE)和免疫组化(SP法)观察.结果 该肿瘤多呈单结节或多结节状浸润性生长,瘤细胞小圆形、核深染、胞质少,呈团、巢状排列,间质有大量增生的纤维结缔组织.免疫表型同时表达上皮性、间叶性和神经源性标记物.结论 促纤维组织增生性小圆细胞肿瘤罕见,临床表现复杂,可发生在腹腔也可在其他部位.肿瘤具有特征性的组织学和免疫组化表现.预后大多较差.     

Intraabdominal desmoplastic small round cell tumor: Cytopathologic findings in two cases

Intraabdominal desmoplastic small round cell tumor (DSRCT) is an extremely rare entity. This study describes fine-needle aspiration, ascitic fluid, and touch imprint cytomorphology of DSRCT in 2 patients with extensive abdomino-pelvic disease. Cytopathologic features were unique and showed good morphologic correlation with subsequent histology of the resected tumor. Immunocytochemical profile and differential diagnosis with other small round cell tumors in this age group are also discussed. Diagn. Cytopathol. 1998;18:449–452. © 1998 Wiley-Liss, Inc.