Clinicopathological and Molecular Spectrum of Ewing Sarcomas/PNETs, Including Validation of EWSR1 Rearrangement by Conventional and Array FISH Technique in Certain Cases

Primary Ewing sarcoma of the kidney: a rare entity with diagnostic challenges

Ewing sarcoma is a very rare tumour with aggressive behaviour and a poor prognosis. It tends to metastasize rapidly. Renal Ewing sarcoma is extremely rare, and only 48 cases have been reported in the literature. Herein, we report the case of a 14-year-old female presenting with a painful left flank swelling. Ultrasound and magnetic resonance imaging showed a large tumour invading the left kidney, heterogeneously enhanced after injection, associated with lymph nodes and peritoneal carcinomatosis. A thoraco-abdomino-pelvic computed tomography scan revealed pulmonary nodules and osteolytic lesions. A biopsy was performed, and histology, immunohistochemistry, and molecular studies confirmed the diagnosis of retroperitoneal Ewing sarcoma. Multi-agent chemotherapy followed by radical nephrectomy was performed, confirming the renal origin, and histology showed a post-therapeutical response. After a 1-year follow-up, there was no evidence of recurrence. We report this case to highlight the rarity of this entity and its challenging clinico-pathological diagnosis when presenting as a renal tumour.

Complex/cryptic EWSR1::FLI1/ERG Gene Fusions and 1q Jumping Translocation in Pediatric Ewing Sarcomas

Ewing sarcomas (ES) are rare small round cell sarcomas often affecting children and characterized by gene fusions involving one member of the FET family of genes (usually EWSR1) and a member of the ETS family of transcription factors (usually FLI1 or ERG). The detection of EWSR1 rearrangements has important diagnostic value. Here, we conducted a retrospective review of 218 consecutive pediatric ES at diagnosis and found eight patients having data from chromosome analysis, FISH/microarray, and gene-fusion assay. Three of these eight ES had novel complex/cryptic EWSR1 rearrangements/fusions by chromosome analysis. One case had a t(9;11;22)(q22;q24;q12) three-way translocation involving EWSR1::FLI1 fusion and 1q jumping translocation. Two cases had cryptic EWSR1 rearrangements/fusions, including one case with a cryptic t(4;11;22)(q35;q24;q12) three-way translocation involving EWSR1::FLI1 fusion, and the other had a cryptic EWSR1::ERG rearrangement/fusion on an abnormal chromosome 22. All patients in this study had various aneuploidies with a gain of chromosome 8 (75%), the most common, followed by a gain of chromosomes 20 (50%) and 4 (37.5%), respectively. Recognition of complex and/or cryptic EWSR1 gene rearrangements/fusions and other chromosome abnormalities (such as jumping translocation and aneuploidies) using a combination of various genetic methods is important for accurate diagnosis, prognosis, and treatment outcomes of pediatric ES.

A rare case report of renal ewing sarcoma/primitive neuroectodermal tumor with ACTH production

Background

Ewing sarcoma/primitive neuroectodermal tumor (PNET) of the renal is extremely rare. The common cause of ectopic ACTH syndrome is pulmonary neuroendocrine tumors, such as small cell carcinomas and carcinoid tumors. Here, we present an unusual case of ectopic ACTH syndrome and hypothyroidism caused by Ewing sarcoma/PNET of the right kidney.

Case presentation

A 19-year-old girl presented with a history of right lumbar pain and discomfort for 2 months, aggravated for 2 days. Abdominal contrast-enhanced computed tomography and computed tomography angiography showed an upper pole occupancy of the right kidney occupancy with subepithelial hemorrhage. Preoperative hormone levels including plasma total cortisol (PTC), adrenocorticotrophic hormone (ACTH) and thyroid hormone measurements were abnormal, indicating that the patient had Cushing syndrome and hypothyroidism. The patient underwent right radical nephrectomy. Histopathological analysis revealed a renal small round blue cell tumor (consistent with a primitive neuroectodermal tumor), with positive immunohistochemistry for CD99 and Ki67 (about 10%) and molecular pathology for EWSR1 gene fusions. PTC, ACTH and thyroid hormone returned to normal after surgery.

Conclusions

We report a rare ectopic ACTH syndrome and hypothyroidism due to renal Ewing sarcoma/PNET. The clinical manifestation of renal Ewing sarcoma/PNET is non-specific and the diagnosis relies on pathological morphology, immunohistochemistry and fusion gene detection. At present, surgery combined with radiotherapy and chemotherapy is used in the treatment, but the prognosis is still not optimistic.

A unique case of adamantinoma-like Ewing sarcoma in the calcaneus, exhibiting prominent squamous differentiation and displaying EWSR1 gene rearrangement

Adamantinoma-like Ewing sarcoma is uncommonly reported in the skeletal sites, including small bones of the feet.A 15-year-old girl presented with pain and swelling in her left foot, leading to difficulty in walking for 8 months. Plain radiograph revealed an ill-defined, lytic-sclerotic lesion without significant periosteal reaction in her left calcaneus. Magnetic resonance imaging (MRI) revealed an expansile lesion involving the anterior calcaneus, which was hypointense on T1 and heterogeneously hyperintense on T2-weighted sequences, infiltrating the adjacent bones and soft tissues. On imaging, the differential diagnoses considered were a giant cell tumor and other primary bone tumors.Histopathological examination revealed a tumor composed of small round cells, with interspersed keratin pearls. Immunohistochemically, the tumor cells were positive for CD99/MIC2, pan-cytokeratin (AE1/AE3), p40, p63, NKX2.2, and synaptophysin. Diagnosis of adamantinoma-like Ewing sarcoma was offered on the initial biopsy. Furthermore, the tumor cells revealed EWSR1 gene rearrangement by fluorescence in situ hybridization, confirming this diagnosis. The patient underwent neoadjuvant chemotherapy, had a poor response, and finally underwent below-knee amputation.This constitutes a rare case of adamantinoma-like Ewing sarcoma in the calcaneus. Ewing sarcoma may be considered as a differential diagnosis for intraosseous lytic-sclerotic lesions, even without significant periosteal reaction, at unusual sites, such as the bones of the foot. Awareness of this entity and application of ancillary techniques is recommended for its exact diagnosis and in differentiating this rare variant from its diagnostic mimics. This case also indicates a poor chemotherapy response in this unusual variant of Ewing sarcoma, occurring in the calcaneus.

Common Pitfalls in Ewing Sarcoma and Desmoplastic Small Round Cell Tumor Diagnosis Seen in a Study of 115 Cases

Ewing sarcoma (ES), “Ewing-like sarcoma” (ELS) and desmoplastic small round cell tumors (DSRCT) can masquerade as other tumor types, particularly neuroendocrine neoplasms and receive inappropriate treatment. We retrieved 115 cases of ES, ELS and DSRCT seen over 17 years in a tertiary center. An initial misdiagnosis or incomplete diagnosis occurred in 6/93 (6.4%) of ES/ELS and 5/22 (22.7%) of DSRCT cases. The most frequent misdiagnosis was small cell neuroendocrine carcinoma. While any misdiagnosis or incomplete classification is almost certainly multifactorial, the most common identified reason for erroneous/incomplete initial reporting was expression of neuroendocrine markers. Other contributing factors included keratin expression, older patient age and apparently unusual tumor location. Most patients treated with a non-sarcoma chemotherapy regimen expired, while those who received a sarcoma-related regimen were alive as of last evaluation. Increased awareness of this diagnostic pitfall is needed in evaluating cases of round cell malignancies.

Evaluation of cell blocks from effusion specimens in Gynecologic Oncopathology: An experience of 220 cases, diagnosed at a Tertiary Cancer Referral Center

One of the common indications of ascitic fluid examination in gynecological oncopathology is the detection and classification of malignant cells, especially in cases of clinically suspicious tubo-ovarian masses. The present study was undertaken to assess and validate the diagnostic utility of cell blocks (CBs) and compare its results with the corresponding conventional smears, prepared from effusion samples. CBs were prepared by thromboplastin technique in 220 cases. In 208 cases, diagnostic concordance between results obtained from smears and corresponding CBs was evaluated. Various antibody markers were tested, as per individual case. The average age of patients was 52.2 years. Positive immunohistochemical (IHC) staining for various markers was observed in 182 cases (82.7%) The most frequently positive antibody marker was PAX8 (101/134), followed by p53 (85/92) [mutation type (either diffusely positive or completely negative)], WT1 (tumor cells) (80/112), calretinin (2/87) (diffuse), BerEP4 (21/49), CA125 (21/24), CK7 (31/39) and CK20 and CDX2, together (5/16). Various other IHC markers utilized, including their positive expression, were TTF1 (1/10), p40 (3/3), p63 (2/4), ER (21/29), HBME1 (1/7), GATA3 (1/4), and MIC2 (1/1). Complete diagnostic concordance between CBs and smears was observed in 170/208 cases (81.7%). There were 20 major discordances, 10 minor and 8 cases with sampling errors. IHC was useful in classifying 158/182 (86.8%) cases, including serous or Müllerian adenocarcinoma (n = 123), mostly high-grade (121); metastatic squamous carcinoma (3); gastrointestinal-type adenocarcinoma (8); pulmonary adenocarcinoma (1); breast adenocarcinoma (1); Ewing sarcoma (1); and mesothelioma (2). CBs are complementary to smears in the detection of gynecological malignancies, mostly high-grade serous adenocarcinomas. These provide an opportunity for testing several IHC markers, for a precise diagnosis, including in various uncommon case scenarios, associated with significant therapeutic implications.

Primitive neuroectodermal tumor of the cervix diagnosed during pregnancy: a rare case report with discussion

Background

Primitive neuroectodermal tumor (PNET) is a relatively rare malignant small round cell tumor, and the occurrence of cervical PNET during pregnancy is extremely rare.

Case presentation

A case of pregnancy complicated by PNET at our hospital was reported. A 19-year-old pregnant woman presented to the hospital due to multiple instances of vaginal bleeding during the first and second trimesters. She was initially considered for threatened abortion but was ultimately diagnosed with cervical PNET. No standard treatment plan has been developed for pregnant women with this tumor. After completing the necessary examinations, doctors cooperated with the patient and her family to develop a surgical treatment plan. The patient recovered well after surgery, but she refused radiotherapy and chemotherapy. After nearly 3 years of follow-up visits, the patient is alive with no signs of recurrence.

Conclusions

PNET during pregnancy is a rare but complex condition. It is necessary to devise an individualized treatment plan according to gestational age. Timely surgical treatment can significantly prolong the survival time of patients but may also lead to fetal loss and the inability to carry a pregnancy.

Curcumin Treatment Identifies Therapeutic Targets within Biomarkers of Liver Colonization by Highly Invasive Mesothelioma Cells-Potential Links with Sarcomas

Simple Summary

Aggressive sarcomatoid tumors designed in inbred strains of immunocompetent rats represent useful tools for both the identification of biomarkers of invasiveness and evaluation of innovative therapies. Our aim was to investigate the molecular determinants of liver colonization and potential common biomarkers of sarcomas and sarcomatoid tumors, using the most invasive (M5-T1) of our four experimental models of peritoneal sarcomatoid malignant mesothelioma in the F344 rat. Using an advanced and robust technique of quantitative proteomics and a bank of paraffin-embedded tumor and tissue samples, we analyzed changes in the proteotype patterns of the liver from normal rats, adjacent non-tumorous liver from untreated tumor-bearing rats, and liver from tumor-bearing rats positively responding to repeated administrations of curcumin given intraperitoneally. The identification of proteome alterations accounting for the antitumor effects of curcumin and changes in the liver microenvironment, which favored the induction of an immune response, could be useful to the research community.

Abstract

Investigations of liver metastatic colonization suggest that the microenvironment is preordained to be intrinsically hospitable to the invasive cancer cells. To identify molecular determinants of that organotropism and potential therapeutic targets, we conducted proteomic analyses of the liver in an aggressive model of sarcomatoid peritoneal mesothelioma (M5-T1). The quantitative changes between SWATH-MS (sequential window acquisition of all theoretical fragmentation spectra) proteotype patterns of the liver from normal rats (G1), adjacent non-tumorous liver from untreated tumor-bearing rats (G2), and liver from curcumin-treated rats without hepatic metastases (G3) were compared. The results identified 12 biomarkers of raised immune response against M5-T1 cells in G3 and 179 liver biomarker changes in (G2 vs. G1) and (G3 vs. G2) but not in (G3 vs. G1). Cross-comparing these 179 candidates with proteins showing abundance changes related to increasing invasiveness in four different rat mesothelioma tumor models identified seven biomarkers specific to the M5-T1 tumor. Finally, analysis of correlations between these seven biomarkers, purine nucleoside phosphorylase being the main biomarker of immune response, and the 179 previously identified proteins revealed a network orchestrating liver colonization and treatment efficacy. These results highlight the links between potential targets, raising interesting prospects for optimizing therapies against highly invasive cancer cells exhibiting a sarcomatoid phenotype and sarcoma cells.

Comparison between Fluorescence in-situ Hybridization (FISH), Reverse Transcriptase PCR (RT-PCR) and fragment analysis, for detection of t (X; 18) (p11; q11) translocation in synovial sarcomas

Background

Synovial sarcoma (SS) is an aggressive, but a relatively chemosensitive soft tissue sarcoma, characterized by a specific, t (X;18)(p11;q11) translocation, leading to formation of SS18-SSX chimeric transcript. This translocation can be detected by various techniques, such as fluorescence in-situ hybridization (FISH), reverse transcriptase PCR (RT-PCR) and fragment analysis.

Objectives

To compare the results of detection of t (X;18)(p11;q11) translocation, across three different platforms, in order to determine the most optimal and sensitive technique.

Methods

Formalin-fixed paraffin embedded (FFPE) tissue sections of 45 soft tissue sarcomas were analyzed, including 16 cases of SS confirmed by histopathology, immunohistochemistry and molecular technique (s)(Group 1); 13 cases, wherein SS was one of the differential diagnosis, preceding molecular testing (Group 2) and 16 cases of various other sarcomas (Group 3). Various immunohistochemical (IHC) markers studied, including INI1/SMARCB1. All cases were tested for t (X;18) translocation, by fragment Analysis, FISH and RT-PCR.

Results

There were 23 cases of SS, including 16 of group 1 and 7 of group 2. By fragment analysis, t (X;18)(p11;q11) translocation was detected in 22/23 cases (95.6%). By FISH, SS18 gene rearrangement was detected in 18/22 cases (78.2%), whereas by RT-PCR, SS18-SSX transcripts were detected in 15/23 cases (65.2%). Immunohistochemically, a unique "weak to absent"/reduced INI1 immunostaining pattern was exclusively observed in 12/13 cases of SS (92.3%). Fragment analysis and FISH were relatively more sensitive techniques. Unique "weak to absent"INI1 immunoexpression significantly correlated with positive t (X;18) translocation results (P = 0.0001).

Conclusion

The present study constitutes first such study from our subcontinent. Fragment analysis is a promising technique for detection of t (X;18)(p11;q11) translocation. FISH and INI1 immunostaining pattern were also relatively more sensitive, over RT-PCR.

Clinicopathologic, immunohistochemical, molecular cytogenetic profile with treatment and outcomes of 34 cases of Ewing sarcoma with epithelial differentiation, including 6 cases with "Adamantinoma-like" features, diagnosed at a single institution, India

To analyze clinicopathological features, including treatment profile of 34 cases of Ewing sarcomas with epithelial differentiation, including 6 cases with adamantinoma-like features. EWSR1 gene rearrangement was tested by fluorescence in-situ hybridization. Thirty-four tumors occurred in 19 males and 15 females (M:F = 1.26:1), with age ranging from 7 to 61 years (average = 24.2); in extremities (17), pelvis (5), paraspinal region (6), head and neck region (3), abdomen (2) and lung (1). Prior to molecular testing, 20/34(58.8%) cases were unequivocally diagnosed as Ewing sarcomas. Histopathologically, the most commonly observed pattern was nesting-type, comprising malignant round cells, including adamantinoma-like features, seen in 6 tumors. Immunohistochemically, tumor cells were diffusely positive (cytoplasmic membranous staining) for CD99/MIC2 (34/34), Fli1 (30/30); focally for synaptophysin (4/16) (25%); variably positive for AE1/AE3(31/32)(96.8%), including diffuse immunoexpression in 4 cases; EMA(6/8) and p40(3/8). All 34 (100%) tumors, tested for EWSR1 rearrangement, displayed positive results. According to the treatment details (available in 24/34 cases, 70.5%), most patients (13/24)(54.1%) were treated with surgical resection and a specific chemotherapy(CT) regimen (neoadjuvant or adjuvant settings), including 7 patients, who received adjuvant radiotherapy. During follow-up (16 cases, 47%), 5 patients developed recurrences and 8 developed metastasis, including a single, who developed recurrence. Finally, 10 patients were alive-with-disease (2-22 months); 6 free-of-disease (5-36 months). This constitutes one of the largest documentation of these rare tumors from our subcontinent, which are diagnostically challenging; require molecular confirmation and associated with treatment implications.

Clinicopathologic features of undifferentiated round cell sarcomas of bone & soft tissues: An attempt to unravel the BCOR-CCNB3- & CIC-DUX4-positive sarcomas

Background & objectives:

Certain genetically defined undifferentiated round cell sarcomas, namely BCOR-CCNB3 and CIC-DUX4 positive, have been described. Here we present detailed clinicopathologic features and molecular results in such cases.

Methods:

Fifty one cases of undifferentiated round cell sarcomas, including 32 cases, tested for BCOR-CCNB3 and CIC-DUX4 fusions, by reverse transcription polymerase chain reaction technique and 44 tumours, for CCNB3 immunostaining, were analyzed.

Results:

Twenty seven (52.9%) tumours occurred in males and 24 (47%) in females; in soft tissues (38; 74.5%), commonly, trunk and extremities and bones (13; 25.4%), frequently, femur and tibia. Five of 32 (15.6%) tested cases were positive for BCOR-CCNB3 fusion and seven (21.8%) for CIC-DUX4 fusions. Histopathologically, CIC-DUX4-positive sarcomas comprised nodular aggregates of round to polygonal cells, containing hyperchromatic nuclei, prominent nucleoli and moderate cytoplasm, with focal myxoid stroma and variable necrosis, in certain cases. BCOR-CCNB3-positive sarcomas mostly comprised diffusely arranged, round to oval to short spindly cells with angulated nuclei, vesicular chromatin, inconspicuous nucleoli and interspersed vessels. Immunohistochemically, tumour cells were positive for MIC2 in 24 of 49 (48.9%) and CCNB3 in 12 of 44 (27.2%) cases. Four of five BCOR-CCNB3-positive sarcomas showed CCNB3 immunostaining and 6 of 7 CIC-DUX4-positive sarcomas displayed WT1 immunostaining. Most patients (27/37) (72.9%) underwent surgical resection and chemotherapy. Median overall survival was 12 months, and disease-free survival was seven months.

Interpretation & conclusions:

Undifferentiated round cell sarcomas are rare; mostly occur in soft tissues of extremities, with CIC-DUX4 positive, as these are relatively more frequent than BCOR-CCNB3 positive sarcomas. CCNB3 and WT1 are useful immunostains for triaging such cases for BCOR-CCNB3 and CIC-DUX4 fusion testing, respectively. Overall, these are relatively aggressive tumours, especially CIC-DUX4-positive sarcomas.

Desmoplastic small round cell tumor showing solid proliferation with limited desmoplasia and confusing immunohistochemical findings: an autopsy report

We herein report a variant case of desmoplastic small round cell tumor (DSRCT) showing limited desmoplasia and confusing immunohistochemical findings. A 26-year-old male was referred for multiple abdominal masses. Laparoscopic biopsy showed only the solid proliferation of small round cells, and he was initially diagnosed with small cell carcinoma. At autopsy, the tumor spread diffusely throughout the abdominal and pelvic cavities. Although the tumor was composed of a predominantly solid pattern of small round cells, multiple samples revealed a fibrous stroma in limited areas only. While immunohistochemistry showed the diffuse expression of desmin, CD99, and bcl-2, epithelial differentiation was unclear with few cytokeratin-positive cells and no staining for the epithelial membrane antigen. Although fluorescence in situ hybridization analysis indicated the EWSR1 gene rearrangement, we were unable to exclude Ewing sarcoma considering the morphological and immunohistochemical findings. The diagnosis of DSRCT was confirmed with a reverse transcription-polymerase chain reaction for EWSR1-WT1 fusion transcripts. DSRCT must be included in a differential diagnosis of small round cell tumors even if desmoplasia is not immediately detected, and thorough sampling and a molecular analysis are mandatory.

Ewing Sarcoma With Emphasis on Extra-skeletal Ewing Sarcoma: A Decade's Experience From a Single Centre in India

INTRODUCTION

The diagnosis of Ewing sarcoma family of tumours (ESFT) is challenging, especially in adults and in extra-skeletal or visceral location. Several morphologic mimics with varied treatment options and prognosis confer diagnostic dilemmas. Application of ancillary diagnostic modalities in surgical pathology in clinical routine has enabled accurate diagnosis of ESFT in bone, soft tissues, and viscera.

AIM

The study aims to assess the clinicopathological features including molecular test results of ESFT with emphasis on sex, age, and location, especially extra-skeletal soft tissue and visceral location.

MATERIAL AND METHODS

Data of clinicopathological, molecular tests (wherever performed), diagnosis rendered in 302 ESFT over a decade from our centre were reviewed. Statistical comparison of skeletal and extra-skeletal tumours with reference to age and sex was done using SPSS package. The P value of <.05 was considered significant.

RESULTS

The cohort included 302 ESFTs with 49% skeletal and 51% extra-skeletal tumours. Thigh was most common site among skeletal tumours; chest wall, paraspinal location, and retroperitoneum among soft tissues (39.4%); and kidney, ovary, and cervix among visceral tumours (11.3%). Fluorescence in situ hybridisation for EWSR1 gene rearrangement was positive in 54 patients and reverse-transcriptase polymerase chain reaction in 19 patients. Predominance of male sex, younger age and location in extremities among skeletal tumours and lack of gender predilection, higher age and axial location in extra-skeletal tumours were noted, which were statistically significant. Molecular tests were performed more frequently in extra-skeletal tumours, especially in visceral tumours to establish the diagnosis.

CONCLUSIONS

The study showed statistically significant differences in the age, sex, and location between skeletal and extra-skeletal ESFT. The increased percentage of extra-skeletal tumours especially in viscera was attributed to the increased awareness and availability of ancillary techniques.

Cranial Ewing Sarcoma/Peripheral Primitive Neuroectodermal Tumors: A Retrospective Study Focused on Prognostic Factors and Long-Term Outcomes

Purpose: Cranial Ewing sarcoma (ES)/peripheral primitive neuroectodermal tumors (pPNETs) are rarely reported because of their extremely low incidence, and the current understanding of these tumors is poor. The purpose of this study was to illustrate the clinical, radiological, and pathological features of cranial ES/pPNETs and to discuss prognostic factors by survival analysis.

Methods: A total of 31 patients who were pathologically diagnosed with cranial ES/pPNETs between 2000 and 2019 were enrolled in this study. To identify which parameters were associated with higher progression-free survival (PFS) and overall survival (OS) rates, univariate and multivariate analyses were performed.

Results: The mean follow-up period was 24.8 months (range, 1–109 months). Eighteen (58.1%) patients had local recurrence and seven (22.6%) patients had distant metastasis. The results of the univariate analysis suggest that the extent of resection and adjuvant radiotherapy are potential prognostic factors for PFS and OS. Adjuvant chemotherapy was associated with OS (P = 0.027) but not with PFS (P = 0.053). The multivariate analysis revealed that the extent of resection and adjuvant radiotherapy were independent prognostic factors for both PFS and OS. In addition, metastasis was an adverse prognostic factor for OS.

Conclusions: Surgical management plays a crucial role in the treatment of cranial ES/pPNETs, and gross total resection should be striven for whenever possible. Post-operative radiotherapy is highly recommended to improve PFS and OS. This study also confirms that metastasis is an adverse prognostic factor for cranial ES/pPNETs.

Five rare cases of Ewing sarcoma, including with epithelial differentiation, involving the female genital tract, displaying EWSR1 rearrangement: Diagnostic challenge and treatment implications

We present clinicopathological and molecular cytogenetic features of five rare cases of Ewing sarcomas, occurring in the female genital tract. A 40 year-old lady presented with a 5.4 cm-sized vaginal mass of 3 months duration, which was histopathologically diagnosed as ES. She defaulted chemotherapy and 8 months later, presented with a recurrence. She underwent chemotherapy and radiotherapy. A 45 year-old lady presented with recurrent vaginal bleeding, for which she underwent total abdominal hysterectomy (TAH) and unilateral salpingo-oophorectomy (USO), 2 and 1/2 years back. Subsequent vaginal biopsy was reported inconclusively, elsewhere. Thereafter, a 5 cm-sized, residual cervicovaginal mass was reported as ES. She completed induction chemotherapy with a significant response. A 35 year-old-lady was referred with a 4 cm-sized cervical mass, for which she underwent TAH-USO with pelvic and para-aortic lymphadenectomy. A 39 year-old-lady presented with a right labial lesion, which recurred. She underwent initial excision, chemotherapy, wide excision and brachytherapy. A year later, she developed multiple metastases; received palliative radiotherapy and died-of-disease. A 16 year-old girl presented with perineal swelling of 4 months duration. She underwent surgical excision of a recurrent right-sided labial cyst, followed by chemotherapy. On histopathological review, all 5 cases were malignant round cell tumors. Immunohistochemically, tumor cells displayed MIC2/CD99 and Fli1 positivity, along with focal positivity for pan cytokeratin (AE1/AE3) (cases 1 and 2) and p63 (case 2). Furthermore, tumor cells in the 1st, 2nd, 3rd and 5th cases displayed EWSR1 rearrangement. Five uncommon cases of ES involving the female genital tract are presented with diagnostic challenges and therapeutic implications.

Ewing's Sarcoma/Peripheral Primitive Neuroectodermal Tumors in Bronchus

Ewing sarcoma/peripheral primitive neuroectodermal tumors (ES/pPNET), a member of the Ewing sarcoma family of tumors, is a malignant soft tissue tumor with small undifferentiated neuroectodermal cells. Primary trachea-bronchial ES/pPNET is very rare. The most common pulmonary ES is due to a metastasis. We describe a case of ES/pPNET which originated in the left basal trunk bronchus. The patient was a 30-year-old male, presenting with irritable cough and fever for 10 days. A tumor of 60 mm in diameter was found in the left basal trunk bronchus, extending to the left lower lobe. No distant metastases were detected. Histopathological examination revealed a malignancy of ES/pPNET with a diffuse proliferation of round cells, a Flexner-Wintersteiner rosette formation and positive staining for CD99. The patient was successfully treated with a combination of left lower lobectomy and adjuvant chemotherapy and has remained disease-free for approximately 18 months at follow-up. This case highlights that ES/pPNET should be considered as a differential diagnosis in cases of trachea-bronchial tumors.

Immunohistochemical Biomarkers of Mesenchymal Neoplasms in Endocrine Organs: Diagnostic Pitfalls and Recent Discoveries

Mesenchymal neoplasms rarely present in or adjacent to endocrine organs. In this context, the recognition of these rare tumor types can be challenging, with significant potential for misdiagnosis as sarcomatoid carcinomas (i.e., anaplastic thyroid carcinoma and sarcomatoid adrenal cortical carcinoma) or neuroendocrine carcinomas, depending upon the dominant histologic patterns. In this review, we address potential pitfalls in diagnosing selected mesenchymal neoplasms arising within or near endocrine organs, including dedifferentiated liposarcoma, synovial sarcoma, angiosarcoma, PEComa, proximal-type epithelioid sarcoma, Ewing sarcoma, and neuroblastoma. For each of these tumor types, we review clinical and pathologic features, histologic clues to distinguish them from endocrine neoplasms, and recently developed immunohistochemical markers that can be particularly useful for establishing the correct diagnosis.

Indian data on bone and soft tissue sarcomas: A summary of published study results

Bone sarcomas are rare tumors, approximating 0.2% of all cancers, with osteosarcoma (OGS), chondrosarcoma, and Ewing sarcoma being the most common cancers in this subset. The formation of disease management groups/clinics focused on sarcomas has resulted in better understanding and management of these uncommon tumors. Multiple large-scale retrospective data from Tata Memorial Hospital (TMH) and All India Institute of Medical Sciences have reported outcomes comparable to Western data in the field of OGS and Ewing sarcoma, with interesting prognostic factors identified for further evaluation. Soft tissue sarcomas are a rare heterogeneous group of tumors, more than 50 different tumor entities. The common subtypes identified in India include Ewing sarcoma and synovial sarcoma. Valuable work regarding brachytherapy has been done by radiation oncologists from the TMH, especially in pediatric patients.

Meningeal Ewing Sarcoma/Peripheral PNET: Clinicopathological, Immunohistochemical and FISH study of four cases

Meningeal Ewing Sarcoma (ES)/peripheral primitive neuroectodermal tumor (pPNET) is a rare diagnostically challenging small round cell tumor in the CNS. This study investigates the clinical pathological features of four cases of this tumor from archives of 6 years in our hospital. Patients were within the median age of 21.5 years and male to female ratio was 1:1. The tumors distributed at the supra-tentorial location, posterior fossa and lumbar vertebral canal, usually presenting as the dura-sited nodule or having close connection with the meninges within the cranium or vertebral canal. Histopathologically, small round undifferentiated tumor cells with hypercellularities, scant cytoplasm and inconspicuous nucleoli were observed, although some components such as atypical larger vesicular nuclei, prominent nucleoli of tumor cells, necrotic foci and mesenchymal collagen proliferation forming the lobular structure, were also appreciated. Immunohistochemally, tumor cells displayed membranous positivity of CD99 (4/4), nuclear positivity of FLI-1 (4/4) and NKX2.2 (4/4), negativity of EMA, GFAP and synaptophysin expression. The histochemical PAS staining showed weak positivity in one case. Fluorescence in situ hybridization (FISH) test using EWSR1 (22q12) dual color break apart rearrangement probe showed positive results in two cases. Results suggest that using a panel of immunohistochemical markers, including NKX2.2, CD99, FLI-1, EMA, GFAP and synaptophysin, combined with the supplementary EWSR1 FISH test, helps to define the diagnosis of meningeal ES/pPNET of CNS.

Defining Ewing and Ewing-like small round cell tumors (SRCT): The need for molecular techniques in their categorization and differential diagnosis. A study of 200 cases

BACKGROUND

Differentiation of Ewing sarcoma family of tumors (ESFT) and Ewing-like tumors remains problematic. Certain ESFT with morphological and immunohistochemical (IHC) profiles lack the EWSR1-ETS transcript. To improve diagnostic accuracy we investigated the presence of several specific transcripts in 200 small round cell tumors (SRCT) displaying ESFT morphology and immunophenotype in which EWSR1 FISH analysis was non-informative or negative.

DESIGN

200 tumors (formalin-fixed, paraffin-embedded) were analyzed by RT-PCR. All tumors were tested for EWSR1-ETS, EWSR1/WT1, PAX3/7-FOX01 or SYT/SSX transcripts, and the negative tumors were subsequently analyzed for CIC/DUX4, BCOR/CCNB3 and CIC/FOX04 transcripts.

RESULTS

133 (66.5%) ESFT displayed one of the above EWSR1-ETS translocations. Three cases (1.5%) revealed the SYT-SSX transcript for Synovial sarcoma, and one (0.5%) a EWSR1-WT1 transcript for Desmoplastic Small Round Cell tumor. The CIC-DUX4 translocation was found in six Ewing-like tumors (3%) with CD99 positivity. The BCOR-CCNB3 gene fusion was observed in 5 tumors (2.5%) displaying round or spindle cells with strong CCNB3 IHC expression in 3 tumors. Moreover, RT-PCR failed to detect any gene fusion transcripts in 19 tumors (9.5%) and were considered "undifferentiated small round cell sarcoma" (SRCS). Molecular biology results were non-informative in 33 SRCTs (16.5%) due to RNA degradation through inadequate fixation and/or decalcification.

CONCLUSION

Our analysis of 200 SRCTs confirms the molecular heterogeneity of neoplasms with ESFT morphology and highlight that molecular studies with RT-PCR including new emerging gene fusion transcripts are mandatory for the diagnosis when EWSR1 FISH is negative or non-informative. The incidence of CIC-DUX4, BCOR-CCNB3 and CIC-FOX04 transcripts was relatively low. A small group of Ewing-like sarcomas or undifferentiated SRCS remains unclassified. Adopting appropriate tissue fixation and processing protocols is important to avoid degradation of fixed/embedded tissue when no frozen tumor is available.