Primary desmoplastic small round cell tumor of bone: report of a case with cytogenetic confirmation

Desmoplastic small round cell tumor of bone revealed by 18F-FDG PET/CT: a case report with literature review

A 50-year-old male presented with neck and shoulder pain. Chest CT and 18F-FDG PET/CT revealed osteolytic bone destruction in the left first rib and thoracic vertebrae with increased FDG uptake. Rib biopsy pathology indicated desmoplastic small round cell tumor (DSRCT).18F-FDG PET/CT can accurately locate the distribution of DSRCT and further guide the location of needle biopsy to assist the DSRCT.

Case Report: Primary Intraosseous Poorly Differentiated Synovial Sarcoma of the Femur

Primary intraosseous poorly differentiated synovial sarcoma is exceedingly rare. Here, we present a case of primary intraosseous poorly differentiated synovial sarcoma from the proximal femur in a 16-year-old girl. The case was initially misdiagnosed, but the correct diagnosis of synovial sarcoma was eventually confirmed by fluorescence in situ hybridization and next-generation sequencing. We review the literature pertaining to synovial sarcoma and show that this case is the second molecularly proven intraosseous poorly differentiated synovial sarcoma in the literature. Recognition of intraosseous synovial sarcoma composed of small round cells is imperative in order to avoid misdiagnosis of the tumor as Ewing sarcoma and other small round-cell tumors, all of which have markedly different clinical management.

Primary Desmoplastic Small Round Cell Tumor of the Femur: Case Report and Review of a Rare Intraosseous Malignancy

Background: Desmoplastic small round cell tumors (DSRCT) are malignant neoplasms of young males arising most commonly in the abdominopelvic cavity, with a subset originating from extra-abdominal soft tissues. As either primary or metastatic lesions, they are rare in intraosseous sites. Case Presentation: We describe the fifth report of primary DSRCT of bone. A healthy 18-year old male presented with a blastic, 17 cm lesion within the left distal femur, suspicious for osteosarcoma or Ewing sarcoma. Subsequent biopsy revealed nests of small round blue cells infiltrating through a desmoplastic stroma. These cells were diffusely positive for epithelial markers, with paranuclear staining for desmin and focal reactivity with NSE. Break-apart FISH revealed a rearrangement in EWSR1, and RNA fusion panel confirmed WT1 as its partner in the pathognomonic t(11;22)(p13;q12) rearrangement. PET/CT showed widespread metastatic disease to visceral and bony sites. Conclusions: Due to their rarity as well as clinicopathologic and immunomorphologic overlap, primary intraosseous DSRCT can create diagnostic challenges with the more frequently encountered tumors of bone.

Immunophenotype-Genotype Correlations in Clear Cell Sarcoma of Kidney-An Evaluation of Diagnostic Ancillary Studies

INTRODUCTION

The purpose of this study was to establish a reliable panel of antibodies for immunohistochemical corroboration of a diagnosis of clear cell sarcoma of kidney (CCSK), taking into consideration the various genotypic subsets of CCSK.

METHODS

We conducted full genotypic analysis for evidence of YWHAE-NUTM2, BCOR internal tandem duplication (ITD), and BCOR-CCNB3 in 68 archival cases of CCSK and then immunostained all cases for CCND1, TLE1, and BCOR along with 63 control samples representing tumor types that may enter into the differential diagnosis of CCSK, including 7 congenital mesoblastic nephromas, 2 desmoplastic small round cell tumors, 13 malignant rhabdoid tumors, 9 Ewing sarcomas/primitive neuroectodermal tumor, 5 synovial sarcomas, and 27 Wilms' tumors.

RESULTS

Molecular assays showed that 54 CCSKs harbored a BCOR-ITD, 1 case expressed a YWHAE-NUTM2 fusion transcript while none expressed the BCOR-CCNB3 fusion. The remaining 13 CCSKs were designated "triple-negative" based on the molecular findings. CCND1 showed positive immunoreactivity across all subgroups. TLE1 was positive in 94% of cases, including 1 YWHAE-NUTM2 fusion-positive case. Three BCOR-ITD-positive tumors were TLE1-negative. BCOR immunostaining was most variable among subgroups, with triple-negative tumors showing the weakest staining. In all, 10/68 (15%) tumors did not stain for BCOR, of which 4 were triple-negative (4/13 = 31%) and 6 were BCOR-ITD-positive (6/54 = 11%). The single YWHAE-NUTM2-positive tumor showed strong staining for all 3 markers. No single case was negative for all 3 stains; however, 3 cases showed no reactivity for either BCOR or TLE1 of which 1 was triple-negative and 2 BCOR-ITD-positive.

CONCLUSION

Having completed the first comprehensive evaluation of immunostaining of 68 fully genotyped CCSK tumors, we show herein that there is a rationale for the use of a small panel of antibodies to assist in the diagnosis of CCSK regardless of genotype, and we demonstrate that in combination CCND1, TLE1, and BCOR are compelling markers in aiding CCSK diagnosis.

Primary desmoplastic small round cell tumor of the tibia: PET/CT and MRI presentation of a rare case and review of the literature

Desmoplastic small round cell tumor (DSRCT) was a soft tissue sarcoma of mesenchymal cell origin that typically exhibited a multi-phenotypic pattern of immunohistochemical staining. DSRCT mainly presented in the abdomen sites and primary occurrence in bone was exceptional. In this study, we reported a new case of primary DSRCT of the tibia in a 33-year-old man who had intermittent pain in the left tibia. Radiographs showed transparent lesions in the left upper tibial. MRI revealed a lobular, lytic and ill-identified lesion with adjacent soft tissues swelling of the upper left tibia. CT confirmed notable destruction and wormlike osteolysis of the bone cortex. PET/CT showed a mass of high uptakes, indicating the malignance. He accepted surgical resection with followed multi-agent chemotherapy, containing vincristine, doxorubicin, ifosfamide and etoposide. Clinically and radiologically, the patient did not show any evidence of recurrence or metastasis at 30 months after surgical treatment. Primary osteogenic DSRCT was extremely rare and should be considered in differential diagnosis of bone tumors.

Pediatric soft tissue tumor pathology: A happy morpho-molecular union

Since its foundation by remarkably talented and insightful individuals, prominently including Pepper Dehner, pediatric soft tissue tumor pathology has developed at an immense rate. The morphologic classification of tumoral entities has extensively been corroborated, but has also evolved with refinement or realignment of these classifications, through accruing molecular data, with many derivative ancillary diagnostic assays now already well-established. Tumors of unclear histogenesis, classically morphologically undifferentiated, are prominent amongst pediatric sarcomas, however, the classes of undifferentiated round- or spindle-cell-tumors-not-otherwise-specified are being dismantled gradually with the identification of their molecular underpinnings. Within recent years, for example, numerous subcategories of 'Ewing-like' round cell sarcoma have emerged. Such advances have provided the basis for novel diagnostic and prognostic sub-classifications. Efforts at defining cell- or lineage-of-origin for several tumor types have produced interesting insights especially for rhabdomyosarcoma. The remarkably early onset of pediatric sarcomas defies the theory necessitating stochastic accumulation of several somatic mutations for cancer development and indeed, these tumors may be remarkably genomically stable, often belying their aggressive nature. Much is coming to light recently regarding the role of epigenetic modifications in the evolution of these sarcomas. Indeed the morphologic features of embryonal tumors generally (not just sarcomas) may be highly reminiscent of arrested differentiation, and given the tight epigenetic regulation of cell fate determination and cell identity maintenance, a theory of epigenetically-driven oncogenesis sits easily with these tumors. The age-delimited distinct biologies of 'pediatric' and adult GIST are intriguing, particularly, the SDH-deficient 'pediatric' form, driven by a metabolic defect, but resulting in epigenetic dysregulation with genome-wide DNA methylation changes. There is little doubt that many of the gaps in our understanding of pediatric sarcoma biology will be filled by a deeper appreciation of the role of dysregulated epigenetics including chromatin biology, perhaps best exemplified in malignant rhabdoid tumor. The field of pediatric soft tissue tumor pathology grows ever more interesting. Importantly though, it must be emphasized, that none of this progress could have occurred, or indeed continue, without the initial step of accurate diagnosis, founded solidly on morphology - thank you Pepper for your unparalleled contributions to this field! The opportunity to be your apprentice for five years has been a bigger and more positive influence than words can express.

Myeloablative chemotherapy with autologous stem cell transplant for desmoplastic small round cell tumor

Desmoplastic small round cell tumor (DSRCT), a rare, aggressive neoplasm, has a poor prognosis. In this prospective study, we evaluated the role of myeloablative chemotherapy, followed by autologous stem cell transplant in improving survival in DSRCT. After high-dose induction chemotherapy and surgery, 19 patients with chemoresponsive DSRCT underwent autologous stem cell transplant. Myeloablative chemotherapy consisted of carboplatin (400–700 mg/m²/day for 3 days) + thiotepa (300 mg/m²/day for 3 days) ± topotecan (2 mg/m²/day for 5 days). All patients were engrafted and there was no treatment-related mortality. Seventeen patients received radiotherapy to sites of prior or residual disease at a median of 12 weeks after transplant. Five-year event-free and overall survival were 11 ± 7% and 16 ± 8%, respectively. Two patients survive disease-free 16 and 19 years after transplant (both in complete remission before transplant). 14 patients had progression and died of disease at a median of 18 months following autologous transplant. These data do not justify the use of myeloablative chemotherapy with carboplatin plus thiotepa in patients with DSRCT. Alternative therapies should be considered for this aggressive neoplasm.

Small cell extraskeletal osteosarcoma: a rare case report

Extraskeletal osteosarcoma is a rare malignant mesenchymal neoplasm and its small cell variant is one among the rarest variant. This article describes a 60-year-old woman presenting with a large, lobulated, painful mass in left thigh with associated history of trauma since 18 months. Her magnetic resonance imaging showed a variegated mixed intensity lesion with associated cystic degeneration, necrosis and matrix arborizing nearby muscles. Fine needle aspiration cytology showed a small cell lesion with very scant osteoid. Tumor was excised and histopathological diagnosis was small cell osteosarcoma involving adjacent muscles and fat with sparing of lymph nodes. The aim of this article is to present the clinical, radiological, cyto-histological and immunohistochemical features of this extremely rare lesion.

Ewing sarcoma

Classification of small round cell tumors of bone is often challenging due to overlapping clinicopathologic features. The purpose of this article is to review the clinical, radiological, histologic, and molecular features of Ewing sarcoma and to provide a discussion of the differential diagnosis of small round cell tumors of bone.

Desmoplastic small round cell tumors with EWS-WT1 fusion transcript in children and young adults

BACKGROUND

The presence of the EWS-WT1 gene fusion transcript (GFT) is characteristic of desmoplastic small round cell tumor (DSRCT), a rare and very aggressive disease for which the treatment has not yet been clearly standardized.

METHODS

This was a retrospective national multicenter analysis of young patients <30 years with tumors expressing the EWS-WT1-GFT, designed to determine whether extensive surgery had an impact on survival.

RESULTS

Between 1995 and 2006, a EWS-WT1-GFT was detected in the tumors of 38 patients, 17 (44.7%) of whom had had a different initial pathologic diagnosis prior to molecular testing. Mean age was 13.2 years (range: 4-29.7 years). Only 9 patients (24%) had localized disease. Treatment was heterogeneous. Nine patients had "limited" surgical resections and 22 underwent "extensive" surgery. Two-year event-free survival and overall survival were 14.4% and 50%, respectively. Among the five patients who were alive in complete remission, four had undergone extensive and complete surgery.

CONCLUSIONS

Detection of the EWS-WT1-GFT plays a major role in the diagnosis of DSRCT. No survival difference was observed according to extent of surgery, but complete surgery seemed to offer the best chance of long-term survival. High-dose chemotherapy or local radiotherapy did not appear to improve survival in this retrospective analysis, but larger prospective studies are needed to provide definitive conclusions on the role of these treatments.

Small Round Cell Tumors of Bone

Diagnosing small round cell tumors (SCRTs) can be a difficult task for pathologists due to overlapping clinicopathologic features. This review highlights the clinical, radiographic, histologic, immunohistochemical, and genetic features of the most common SRCTs involving bone with an emphasis on differential diagnosis. SRCTs are a heterogeneous group of neoplasms characterized by poorly differentiated cells with small, blue, round nuclei and scant cytoplasm. They can occur as primary tumors in bone or soft tissue.

Primary malignant bone tumors--recent developments

Primary malignant bone tumors are rare sarcomas with an estimated frequency of about 2900 new cases per year; they constitute less than 0.2% of all cancers diagnosed in the United States. The diagnosis and management of these neoplasms require a team approach, which includes orthopaedic surgeons, radiologists, pathologists, and oncologists. With this approach and current treatment modalities, the 5-year survival for the most common malignant bone tumors, osteosarcoma and Ewing sarcoma, are 70% and 60%, respectively. This review will summarize recent developments and advances in molecular pathogenesis of the more common primary malignant bone neoplasms.

[Desmoplastic small round-cell tumor: two cases of diffuse abdominopelvic infiltration]

Desmoplastic small round-cell tumors are a rare malignant tumor that affects male children and young adults. It frequently presents as a large abdominal mass with widespread peritoneal involvement at diagnosis. We report two cases of desmoplastic small round-cell tumors, with diffuse infiltration in the abdomen and pelvis in two adult caucasian males. The first case-report is a middle-aged man and the second a young adult man with early recurrence and diffuse metastatic lymph nodes. Both tumors have a distinct morphology, a polyphenotypic differentiation and a t(11;22) (p13;q12) translocation. The prognosis remains poor and leads to death in most cases, despite surgical resection, radiotherapy and high-dose chemotherapy.

Intracerebral small round cell tumor: an unusual case with EWS-WT1 translocation

Desmoplastic small round cell tumor (DSRCT) is a rare tumor, seen both in children and young adults with a marked predilection for the peritoneal cavity. Histology showed a small round cell tumor with a fibromyxoïd stroma and immunohistochemistry indicated neural and mesenchymal differentiation, and diagnosis was made by molecular detection of the EWS-WT1 fusion gene product. DSRCT should be considered in the differential diagnosis of intracranial small round cell tumors.

Primary desmoplastic small round cell tumor of the femur

Desmoplastic small round cell tumor (DSRCT) is a rare malignant neoplasm typically involving the abdominal cavity of a young male. Extra-abdominal occurrence of this tumor is very rare. We report a 10-year-old girl with primary DSRCT arising within the left femur. The patient presented with knee pain, and radiological findings were strongly suggestive of osteogenic sarcoma. In addition to the typical microscopic appearance and immunophenotype, RT-PCR demonstrated the chimeric transcript of EWS-WT1, which is diagnostic of DSRCT. Pulmonary metastases were present at initial staging studies, but no abdominal or pelvic lesion was present. Despite chemotherapy and complete tumor excision, the patient developed progressive lung and bone metastases and died 3 years after initial presentation. This is the second reported case of primary DSRCT of bone with genetic confirmation.

Small Round Cell Tumors of Bone

Context.—Primary small round cell tumors of the bone are a heterogeneous group of malignant neoplasms presenting predominantly in children and adolescents. They include Ewing sarcoma/peripheral neuroectodermal tumor or Ewing family tumors, lymphoma, mesenchymal chondrosarcoma, and small cell osteosarcoma. Even though they share many morphological similarities, their unique biological and genetic characteristics have provided substantial insights into the pathology of these diverse neoplasms.

Objective.—To provide an overview of the clinical, radiologic, pathologic, and genetic characteristics of these tumors along with a pertinent review of the literature.

Data Sources.—A literature search using PubMed and Ovid MEDLINE was performed, and data were obtained from various articles pertaining to clinicopathologic, biological, and genetic findings in these tumors. Additionally, findings from rare cases have been included from author's subspecialty experience.

Conclusion.—The diagnosis of small round cell tumors can be made accurately by applying clinicopathologic criteria, as well as a panel of immunohistochemical and genetic studies in appropriate cases. Molecular genetic studies may provide further insight into the biology, histogenesis, and prognosis of these tumors.

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.