Fine-needle aspiration of intra-abdominal desmoplastic small cell tumor

Desmoplastic Small Round Cell Tumors: A review with focus on clinical management and therapeutic options

Desmoplastic Small Round Cell Tumors (DSRCTs) are an entity of rare, aggressive soft tissue sarcomas described by Gerald and Rosai in 1989. It predominantly affects male adolescents and young adults, with a peak incidence between an age of 20 and 30 years. Typically, DSRCT demonstrate as multiple small tumor nodules within the abdominal cave, retroperitoneum and pelvis. In more than 50% of the cases, the neoplasm presents metastatic at the timepoint of diagnosis. Histologically, DSRCTs have a characteristic morphology with sharply demarcated islands of uniform small round cells in abundant desmoplastic stroma organized in loose extracellular matrix. Immunohistochemistry reveals a polyphenotypic differentiation with co-expression of epithelial, myogenic, mesenchymal and neural markers. The morphology is highly variable and can hinder diagnosis. The most consistent molecular characteristic of DSRCT is the reciprocal t(11;22)(p13q12) translocation. This mutation leads to a formation of the EWSR1-WT1 fusion oncogene, which encodes for a chimeric protein with transcriptional regulatory activity and is regarded as driving source of the disease. To date, there is no standardized concept for clinical management, staging and treatment. Patients receive an aggressive multimodal therapeutic approach consisting of chemotherapy, radical surgical procedures, hyperthermic, intraperitoneal chemotherapy (HIPEC) and radiation. New targeted therapies are used in experimental settings as salvage therapy. So far, none of these therapies showed significant long-term success. This review gives an overview of diagnostic difficulties and pitfalls, discusses therapeutic strategies and highlights options for clinical management.

Desmoplastic Small Round Blue Cell Tumor: A Review of Treatment and Potential Therapeutic Genomic Alterations

Desmoplastic small round blue cell tumors (DSRCTs) originate from a cell with multilineage potential. A molecular hallmark of DSRCT is the EWS-WT1 reciprocal translocation. Ewing sarcoma and DSRCT are treated similarly due to similar oncogene activation pathways, and DSRCT has been represented in very limited numbers in sarcoma studies. Despite aggressive therapy, median survival ranges from 17 to 25 months, and 5-year survival rates remain around 15%, with higher survival reported among those undergoing removal of at least 90% of tumor in the absence of extraperitoneal metastasis. Almost 100% of these tumors contain t(11;22) (p13;q12) translocation, and it is likely that EWS-WT1 functions as a transcription factor possibly through WT1 targets. While there is no standard protocol for this aggressive disease, treatment usually includes the neoadjuvant HD P6 regimen (high-dose cyclophosphamide, doxorubicin, and vincristine (HD-CAV) alternating with ifosfamide and etoposide (IE) chemotherapy combined with aggressively attempted R0 resection). We aimed to review the molecular characteristics of DSRCTs to explore therapeutic opportunities for this extremely rare and aggressive cancer type.

Desmoplastic Small Round Cell Tumor

Desmoplastic small round cell tumor (DSRCT) is an aggressive small round cell neoplasm which predominantly occurs intra-abdominally in adolescents and young adults with a male predominance, and which is characterized by a recurrent t(11;22)(p13;q12) translocation leading to formation of the EWSR1-WT1 fusion gene, which generates a chimeric protein with transcriptional regulatory activity. Histologically, DSRCT has a characteristic morphology, of islands of monotonous small cells within prominent sparsely cellular fibroblastic stroma, and immunohistochemically it shows polyphenotypic multidirectional differentiation, with expression of epithelial, muscle, and neural markers. However, DSRCT can arise more rarely in other sites and exhibit a spectrum of both histologic features and immunoprofile, which may confuse diagnosis with other small round cell neoplasms. Correct diagnosis is important to ensure correct treatment and prognostication; DSRCT are almost universally fatal neoplasms with patients usually succumbing to disease within the first 2 years of diagnosis. While combination treatment strategies can confer a survival benefit, the overall prognosis remains poor. Further insight into the tumorigenic molecular changes generated by the fusion oncogene may lead to the generation of specific targeted therapies. We review DSRCT, discussing morphology and immunohistochemistry, molecular genetic findings, potential targeted treatments, and the differential diagnosis.

Fine-needle aspiration in desmoplastic small round cell tumor: a report of 10 new tumors in 8 patients with clinicopathological and molecular correlations with review of the literature

BACKGROUND

Desmoplastic small round cell tumor (DSRCT) is a rare round cell sarcoma entity characterized by a specific t(11;22)(p13;q12) translocation, usually intra-abdominal localization and an aggressive clinical outcome. To date, only 35 DSRCT cases diagnosed by fine-needle aspiration have been described.

METHODS

This study reports the cytological diagnosis of DSRCT. Ten tumors from 8 patients were sampled for diagnosis and analyzed to search the characteristic translocation using fluorescence in situ hybridization or reverse transcription polymerase chain reaction methods.

RESULTS

Smears were always hypercellular and consisted of nonspecific round cell sarcoma. Nuclei were polymorphic round, kidney-, or heart-shaped. Nuclear molding was usually present. Paranuclear cytoplasmic densities were obvious and noted in 7 cases. Cytonuclear atypia, mitotic figures, numerous crushed nuclei, and apoptosis were frequently seen. Purple-stained stroma was present in 8 cases (ranging from few connective tissue fragments to large hyalinized deposits). Molecular studies based on cytological aspirates were performed in 8 patients. The presence of the fusion gene EWSR1-WT 1 transcript was identified in all, which confirmed the diagnosis of DSRCT.

CONCLUSIONS

Smears showing poorly differentiated round cells associated with cytoplasmic densities and connective stoma, in a specific clinical context, young adult age, intra-abdominal localization, suggestive immunocytochemical profile, and a unique cytogenetic abnormality are highly specific and allow an accurate diagnosis of DSRCT.

Desmoplastic small round cell tumor of the pleura

Desmoplastic small round cell tumor (DSRCT) is a rare neoplasm with aggressive behavior. Usually it presents as a peritoneal mass, although other cases in various locations have been described. Since less than 10 cases of primary DSRCT in the pleura have been described, it is of interest to report a pediatric case arising from the pleura. The diagnosis was confirmed by molecular detection of the EWS/WT-1 fusion gene product. Multidisciplinary treatment with chemotherapy, radiotherapy, and surgical resection resulted in a progression-free survival time above the median survival, suggesting that this conventional approach could prove effective for this rare and very aggressive malignancy.

Cytology of desmoplastic small round-cell tumor: comparison of pre- and post-chemotherapy fine-needle aspiration biopsies

BACKGROUND

Desmoplastic small round-cell tumor (DSRCT) is an aggressive malignancy of young adults, which is amenable to fine-needle aspiration biopsy (FNAB). As this entity is increasingly recognized and biopsied, cytopathologists are compelled to become familiar with the range of cytologic features of DSRCT. In addition, postchemotherapy tumors may be sampled to confirm disease recurrence before planning additional therapy. This study was designed to compare prechemotherapy and postchemotherapy cytomorphology of DSRCT and to evaluate for distinct chemotherapy-induced changes.

METHODS

The authors searched their respective institutional databases for all DSRCT cases with an associated FNAB. FNAB slides, immunocytochemistry, and cytogenetic results were reviewed.

RESULTS

Six aspirates from 5 patients were identified, 3 of which were postchemotherapy. The postchemotherapy cases demonstrated cytologic findings not typically described in DSRCTs, including prominent and conspicuous nucleoli, discohesive single-cell architecture, and slightly larger cell size.

CONCLUSIONS

Cytomorphologic variability was prominent in prechemotherapy cases, and no case could be classified as DSRCT on cytology alone; immunohistochemistry was necessary for definitive diagnosis. Chemotherapy increased the spectrum of cytologic features. The most notable difference between the 2 groups was a predominantly discohesive single-cell pattern with conspicuous nucleoli in the postchemotherapy group, instead of the clustering pattern of medium-sized cells with inconspicuous nucleoli typically attributed to de novo cases reported in the literature.

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.

Percutaneous image-guided fine-needle aspiration of peritoneal lesions

Fine-needle aspiration (FNA) is a widely accepted technique for the initial tissue diagnosis of a variety of lesions arising within retroperitoneal and intraabdominal viscera. Fear of complications secondary to perforation of the bowel wall has limited the use of FNA in the diagnosis of gastrointestinal and peritoneal masses. A variety of primary and secondary neoplasms involving the peritoneum may present as multiple nodules, as masses, or as diffuse involvement of the peritoneum. When these lesions are associated with mass lesions or areas of significant peritoneal thickening, they become amenable to percutaneous image-guided FNA. We report on our experience with a series of 23 peritoneal lesions investigated by FNA for which subsequent histologic confirmation was available in 19, along with an additional 4 cases without histologic confirmation. One to four passes were made into each lesion, and immediate assessment for adequacy was performed by a cytopathologist in all cases. All 17 cases with a specific cytologic diagnosis and histologic confirmation represented either primary or metastatic neoplasms (5 gastrointestinal stromal tumors, 4 metastatic melanomas, 2 mesotheliomas, 1 lymphoma, 1 example of Kaposi's sarcoma, 1 serous papillary carcinoma of ovarian origin, 1 mucinous adenocarcinoma of ovarian origin, 1 intraabdominal desmoplastic small-cell tumor, and 1 solitary fibrous tumor of the peritoneum). In an additional 4 cases, the aspirates were judged as insufficient for diagnosis, with the smears containing only blood and benign mesothelial cells and/or inflammatory cell elements. These four smears were associated with both neoplastic and nonneoplastic lesions. Surgical confirmation was obtained in only 2 of these cases (1 metastatic melanoma and 1 example of omental and peritoneal involvement by an ovarian adenocarcinoma). Two cases without histologic confirmation were associated with clinically confirmed metastases. In our series, no acute or chronic postprocedural complications were identified, indicating that FNA in this setting is a safe technique. Accurate cytologic diagnosis was achieved in 74% of cases. The overall insufficiency rate was 26%.

Cytology of desmoplastic small round cell tumor

BACKGROUND

Desmoplastic small round cell tumor (DSRCT) is a high-grade malignant tumor that has a predilection for adolescent males and usually affects the abdominal cavity. The cytology literature regarding DSRCT, including aspirates and ascitic fluid, is limited. To the authors' knowledge, findings in ThinPrep slides have not been described previously.

METHODS

Seven cytologic specimens from five patients with histologically confirmed DSRCT were reviewed. Five specimens were fine-needle aspiration biopsies (FNABs), (liver, flank soft tissue, abdomen, and two resected colons [pericolic]) and two specimens were ascitic fluid. Cytologic features were studied in ThinPrep slides and direct smears, which included hematoxylin and eosin, Papanicolaou, and Quik-Dip stains.

RESULTS

All specimens showed moderate to high cellularity. The tumor cells were arranged singly and in clusters. The cells demonstrated high nuclear/cytoplasmic ratios, granular chromatin reminiscent of small cell carcinoma, usually inconspicuous nucleoli, smooth to irregular nuclear membranes, and frequent nuclear molding. The cytoplasm was scant to moderate, pale blue, and occasionally vacuolated. Pseudorosettes were observed in six specimens. One ThinPrep slide and the direct smears contained cells with perinuclear, cytoplasmic densities. Stromal fragments were present in the direct smears but were uncommon in ThinPrep. Three specimens were diagnosed as being consistent with DSRCT. Two specimens were diagnosed as malignant small cell tumor. Molecular studies performed on histologic material in four cases confirmed the presence of the diagnostic translocation, t(11;22)(p13;q12).

CONCLUSIONS

DSRCT may be diagnosed accurately in cytology specimens. Characteristic cytologic features include granular chromatin, smooth to irregular nuclear membranes, nuclear molding, cytoplasmic vacuoles, pseudorosettes, and metachromatic stroma. Cytoplasmic densities may be observed in direct smears and ThinPrep slides.

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.

Desmoplastic small round cell tumor with primary ovarian involvement: case report and review

BACKGROUND

Desmoplastic small round cell tumor (DSRCT) is a rare, aggressive, malignant neoplasm that has recently been characterized. It has not been associated with a primary visceral organ. In women, cases are even more rare and often have some ovarian involvement.

CASE

An 11-year-old girl presented with abdominal pain, nausea, and vomiting. A CT scan revealed a large heterogeneous pelvic mass with cystic components and an 8-cm midabdominal mass. During exploratory laparotomy, the patient was found to have a pelvic mass measuring 12. 9 cm replacing normal ovarian tissue. The midabdominal mass was also removed. Pathology, cytology, and immunohistochemistry confirmed a desmoplastic small round cell tumor. Even with aggressive surgical and medical intervention, the patient died 11 months after initial diagnosis.

CONCLUSION

We present a rare small cell tumor that is associated with ovarian involvement. The prognosis in these patients is extremely poor and very few survivals have been reported.

Fine-needle aspiration biopsy diagnosis of small round cell tumors of childhood: A comprehensive approach

Fine-needle aspiration biopsy findings in small round cell malignant tumors of children are briefly reviewed. All of these tumors usually have characteristic cytomorphology which, when recognized, may lead to a definitive diagnosis. However, when these tumors are undifferentiated, morphologic criteria may not be sufficient for arriving at a correct diagnosis. A variety of ancillary studies including electron microscopy, immunohistochemistry and DNA ploidy, cytogenetics, and fluorescent in situ hybridization may provide valuable additional information for precise characterization of these neoplasms. Some of the ancillary studies may also be used for assigning these cases to prognostically significant subgroups. This information may also help in defining the most suitable chemotherapeutic regimens for these tumors. Since most of these special studies require only a small amount of cellular material, fine-needle aspiration biopsy is ideally suited for obtaining samples for these procedures. It is hoped that as cytogenetic and molecular techniques become available in many diagnostic laboratories, a comprehensive evaluation of aspiration biopsies from round cell malignant tumors, encompassing a precise pathologic diagnosis, determination of prognosis, and prediction of response to therapy, will be possible in a majority of cases. Diagn. Cytopathol. 1999;21:81-91.

Biphasic intraabdominal desmoplastic small round cell tumor: fine-needle aspiration cytology findings

The present report describes the case of a 9-yr-old boy with an abdominal desmoplastic small round cell tumor (DSRCT) which on fine-needle aspiration cytology and histology revealed a biphasic pattern, making initial diagnosis difficult. Epithelial-like clusters of cells and loosely-arranged poorly-differentiated cells with scant cytoplasm associated with cells having a larger nucleus and multinucleated larger cells represented the smears' counter-part of epithelial clusters and lobules and sarcomatous-like tissue recognized in the histologic sections. Multinucleated cells were common in the sarcomatous-like areas of the tumor. The biphasic pattern was highlighted by immunohistochemistry. Keratin and epithelial membrane antigen stained predominantly or only the epithelial component, while desmin diffusely decorated the sarcomatous areas and the epithelial cells as a paranuclear cytoplasmic dot. Immunosera 013 mainly stained the sarcomatous component.