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.     

Desmoplastic small round cell tumors: cytologic, histologic, and immunohistochemical features

Desmoplastic small round cell tumor (DSRCT) is a recently recognized clinicopathologic entity that has a predilection for adolescent males and usually affects the abdominal cavity. Due to its uncommon nature, many pathologists lack experience with this tumor. The literature regarding DSRCT is reviewed with special attention to its histologic and cytologic diagnosis. Morphologic features of DSRCT and its immunohistochemical and cytogenetic profile are summarized and differential diagnosis with other small round cell tumors is discussed. As observed by both histologic and cytologic examinations, small round blue cells and fibrosclerotic stroma are the striking morphologic features of DSRCT. The typical immunohistochemical profile is characterized by coexpression of epithelial, mesenchymal, myogenic, and neural markers. Cytogenetically, this tumor harbors a specific karyotypic abnormality, namely t(11;22)(p13;q12). These features distinguish DSRCT from other members of the family of small round cell tumors.     

Desmoplastic small round cell tumor: a clinical, pathological, and immunohistochemical study of 18 Chinese cases

Desmoplastic small round cell tumor (DSRCT) was first reported in 1989. Generally, DSRCT is considered to be an aggressive malignant neoplasm that mainly occurs in the abdominal cavity and has been often seen in adolescents and young male adults. In the present study, a total of 18 cases of DSRCT reported in China between October 1998 and June 2006, including one case treated by the authors, were reviewed and analyzed. Among them, 14 had tumors in the abdominal cavity; the other four cases had tumors in the left fossa orbitalis, the root of the tongue, the soft tissue behind the left eyeball, and the abdominal wall (umbilicus). Overall, the 1-year, 3-year, and 5-year survival rates were 52.36%, 27.92%, and 27.92%, respectively. The survival rate of DSRCT patients is disappointing; however, the survival of patients who had resection of the tumor or received comprehensive clinical treatment is satisfactory.     

A comprehensive diagnosis of a desmoplastic small round cell tumor of unusual location based on fine‐needle aspiration cytology: Report of a case arising in the parotid gland and review of the literature

Desmoplastic small round cell tumor (DSRCT) is rare and a highly aggressive neoplasm that typically involves the soft tissues of the abdomen or pelvis in children or young adults, showing a male predilection. Although it can occurs over a wide age range, the peak incidence is in the third decade of life. DSRCT usually shows widespread abdominal serosal involvement, and overall patient survival is poor. On the other hand, extra‐abdominal DSRCT is very rare. DSRCT in major salivary glands has been reported, but it is extremely rare. In the majority of reported series diagnosis is made by the histological analysis of FFPE tissues together with immunohistochemistry (IHC) and molecular analysis, particularly the demonstration of chromosomal translocation involving EWSR1. Very few cases have been diagnosed so far by Fine Needle Aspiration (FNA) cytology. Moreover ancillary studies have been performed in all reported cases in FFPE samples. There is still controversy and lack of consensus regarding the suitability of cytological samples especially smears for immunocytochemical (ICC) and fluorescence in situ hybridization (FISH), what makes its standardization difficult. We report a case of a primary DSRCT of parotid gland in a 17‐year‐old male diagnosed by FNA cytology. The cytomorphological diagnosis was coupled with ICC and FISH analysis performed on stained smears. We emphasize the feasibility and reliability of cytological smears for the application of immunocytochemical and molecular techniques.     

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 tumour of unknown primary origin with lymph node and lung metastases: histological, cytological, ultrastructural, cytogenetic and molecular findings

 Desmoplastic small round cell tumour (DSRCT) is an extremely aggressive neoplasm belonging to the family of ”small round blue cell tumours”, which includes primitive neuroectodermal tumour (PNET), Wilms’ tumour and Ewing’s sarcoma. DSRCT is considered to be a neoplasm derived from a primitive cell. It is immunohistochemically reactive with epithelial, neuronal and mesenchymal cell markers, demonstrating divergent differentiation along three cell lines. Originally thought to arise from serosal surfaces, the tumour has recently been reported in the central nervous system and ovary. The tumour in this case is a neoplasm that meets the histological, immunohistochemical, cytological and cytogenetic criteria of DSRCT; it is not associated with serosal membranes, and it has supraclavicular and axillary lymph node deposits and multiple pulmonary and brain metastases. Tumour cells from our case show cytogenetic similarities with Ewing’s sarcoma and PNET. Electron microscopic findings suggest similarities between DSRCT and Wilms’ tumour. Cloning and sequencing of PCR products showed in-frame fusion of EWS exon 7 to WT1 exon 8. Received: 18 August 1997 / Accepted: 26 September 1997     

促纤维组织增生性小圆细胞肿瘤^18F-FDG PET-CT影像学表现及文献复习

目的探讨促纤维组织增生性小圆细胞肿瘤（DSRCT）的正电子发射体层摄影术（PET）-CT影像表现、诊断、鉴别诊断。方法经病理组织证实的2例DSRCT患者,男性,年龄均为27岁。回顾性分析其PET-CT影像学特点,并文献复习。结果PET影像表现为广泛腹、盆腔内不均质性葡萄糖代谢异常活跃灶,肿块内坏死区葡萄糖代谢呈缺失表现。CT表现为腹、盆腔内分叶状结节或团块状肿块,广泛侵及腹膜、网膜、浆膜面;内可见坏死区,伴点状钙化;增强CT呈轻中度不均质性强化,病灶对周围组织、器官呈推挤、包绕、侵犯倾向,边界不清,但与周围器官无明显起源关系。MRI显示：T1加权像病灶呈不均质性等、低信号,T2加权像病灶呈不均质性等、稍高信号,坏死区呈高信号,增强扫描呈不均质性轻中度强化。结论DSRCT罕见,临床表现复杂,病灶与浆膜关系密切,但也可发生在其他部位;PET-CT可以同机融合结构及功能显像行全身扫描,对DSRCT的诊断、分期、定位活组织检查及疗效评价有很高价值。     

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.     

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.     

促结缔组织增生性小圆细胞肿瘤的临床病理学研究

目的探讨促结缔组织增生性小圆细胞肿瘤（DSRCT）的细胞学和组织学形态、免疫学表型以及在石蜡包埋组织中检测EWS-WT1融合基因的可行性。方法回顾性复习15例DSRCT的临床资料、1例细胞学形态、14例组织学形态和15例免疫学表型,采用逆转录聚合酶链反应（RT-PCR）法检测1例石蜡包埋组织中的EWS-WT1融合性mRNA,经测序证实并确定融合类型。结果13例为男性,2例为女性,年龄范围12～38岁,平均23．8岁。临床上多表现为腹部不适、腹胀、腹痛和腹部包块,伴有呕心、便秘和体重减轻等症状。体检显示,多数病例于中下腹可触及质硬肿块,境界不清,活动度差。影像学检查显示腹腔或盆腔内多个或单个结节状肿块,直径为3—25cm,平均8．6cm。细胞学涂片显示,在出血性的背景中可见散在、成簇的小圆细胞,核染色深,核仁不清,核分裂象易见,胞质稀少。组织学上,肿瘤由深染的小圆细胞、卵圆形细胞及短梭形细胞组成,呈大小不一、外形不规则的巢状排列,大的瘤巢中央可见坏死,瘤巢之间为大量增生的纤维结缔组织,可伴有玻璃样变性。所有病例均弥漫强阳性表达AE1／AE3、波形蛋白、结蛋白和神经特异性烯醇化酶,部分病例尚表达CAM5．2、上皮膜抗原、CD57、嗜铬粒素A、突触素和WT1,不表达肌生成素、CK5／6、CD117、钙（视）网膜蛋白和CD99。RT-PCR检测出EWS-WT1融合性mRNA,测序结果显示由EWS基因的7号外显子与WT1基因的8号外显子融合所产生,融合性基因含有KTS序列。结论（1）DSRCT是一种好发于青少年男性腹腔和盆腔内、具有多向性分化的高度恶性小圆细胞肿瘤。（2）瘤细胞特征性的波形蛋白和结蛋白核旁点状染色,在DSRCT的诊断和鉴别诊断中具有十分重要的价值。（3）在石蜡包埋的DSRCT组织中能检测出EWS-WT1融合基因的转录产物,RT-PCR可作为DSRCT一项实用的分子遗传学诊断手段。     

Two autopsy cases of desmoplastic small round cell tumor

Desmoplastic small round cell tumor (DSRCT) is a rare aggressive malignant tumor. It is a refractory tumor and the median overall survival is very short. We report two autopsy cases of DSRCT, both of which were already advanced and metastasized at the first medical examination. Both cases showed typical DSRCT findings in terms of localization of the lesions, histopathology and genetics, but the rate of disease progression was quite different. Survival after initial symptoms in Case 1 was only 12 months. On the other hand, survival after primary hospitalization in Case 2 was 42 months. The Case 2 patient initially received chemotherapy for advanced pancreatic carcinoma, because a nodule of the pancreatic tail was found on computed tomography (CT) scan. After chemotherapy, tumor regression was observed on CT scan. It is thus implied that adoption of the regimen for pancreatic carcinoma might have been one of reasons of the long survival in Case 2.     

Desmoplastic small round cell tumor (DSRCT) with ovarian involvement in 2 young women.

We report 2 cases of desmoplastic small round cell tumor (DSRCT) involving the ovaries in young women. The first patient presented with symptoms of acute appendicitis and the second patient presented with a mass in the lower abdomen and slightly elevated CA-125 level. In both patients, the tumor was widely metastatic at presentation. The ovarian involvement was unilateral in the first patient and bilateral in the second with tumor size ranging from 9 to 11 cm. Morphology, immunohistochemistry, and molecular cytogenetics were consistent with DSRCT. Despite tumor debulking and multiple chemotherapy regimens, the first patient died at 20 months after initial diagnosis and the second is still undergoing chemotherapy at 7 months after initial presentation. To gain additional insight on DSRCT with ovarian involvement, the literature was reviewed and summarized.