A Modification of the American Joint Committee on Cancer Nomogram for Undifferentiated Sarcoma With External Validation and Risk Stratification

BACKGROUND

The aim of this study is to establish a model to predict the overall survival (OS) and stratify the risk of postoperative patients with undifferentiated sarcoma.

METHODS

A total of 452 postoperative patients with undifferentiated sarcoma in the trunk and extremity from the Surveillance, Epidemiology, and End Results database were enrolled as the training cohort. We collected a group of 163 undifferentiated sarcoma patients from our center as the external validation cohort. Cox proportional hazards regression model was used to screen survival-associated factors for the construction of the nomogram. Concordance-indexes (C-indexes), calibration curves, and receiver operating characteristics (ROCs) curves were applied for the discrimination and calibration of the nomogram. The cutoff value of nomogram-based total points was applied to stratify the risk of patients.

RESULTS

A nomogram was developed incorporating four independent factors: age, tumor site, eighth AJCC stage, and radiotherapy. The nomogram showed good prognostic accuracy and excellent agreement in the training and validation cohort, with C-indexes of .701 (95% confidence interval [CI]: .683-.719) and .700 (95% CI: 0.659-.741), respectively. Furthermore, we identified the best cutoff value of nomogram total points (103.2) as the predicted risk and divided the patients into a high-risk group and a low-risk group. Significant differences in OS between the two groups were indicated in the training cohort and external validation cohort, showing the appreciable clinical validity and clinical utility of the nomogram (P < .001).

CONCLUSION

This nomogram provides an insightful and applicable tool for individual evaluations and the distinguishment of risk for patients with undifferentiated sarcoma.

Case report: The first account of undifferentiated sarcoma with epithelioid features originating in the pleura

Undifferentiated epithelioid sarcoma (USEF) is a rare subtype of undifferentiated soft tissue sarcoma that presents unique challenges in clinical diagnosis and treatment. Here, we report a case of USEF occurring in the pleura of a 51-year-old man for the first time. Thoracoscopic examination revealed widespread nodular changes, and pathological analysis confirmed the presence of numerous epithelioid atypical cells. Immunohistochemical (IHC) analysis demonstrated an undifferentiated phenotype with distinct characteristics: epithelial membrane antigen (foci +), vimentin (+), Ki-67 (+70% +), TTF-1 (+), P53 (mutant type +90%), INI-1 (+), and CK5/6 (small foci +). Immunohistochemical examination of the tumor showed that the tumor was an undifferentiated epithelioid sarcoma. High-throughput DNA sequencing revealed pivotal mutations, including a nonsense mutation in the NF1 gene (c.641A > G(p.H214R)). and critical TP53 missense mutation (c.641A > G(p.H214R)). This TP53 mutation, with a tumor mutation burden of 16.5 Muts/Mb, signifies a high level of genomic instability, likely contributing to the rapid progression and aggressiveness of the disease. Detection of the TP53 mutation provides essential insights, indicating the disease's rapid progression and highlighting the potential for targeted therapies. Although the patient's disease progressed extremely rapidly and he tragically died within a week, we discussed the results of IHC and DNA sequencing in detail and discussed his possible treatment options. Insights gained from this case will be critical in shaping future diagnostic and therapeutic paradigms for USEF, particularly in the context of TP53 mutations.

Pleomorphic undifferentiated sarcoma of the mediastinal thymus: A case report and literature review

Pleomorphic undifferentiated sarcoma (PUS) of the mediastinal thymus is a rare type of cancer. In the present case report, a 67-year-old female patient presenting a mediastinal mass for >1 year was assessed for clinical characteristics, histopathological, immunohistochemical expression and gene mutation using fluorescence in situ hybridization (FISH), and relevant literature was reviewed. Histological analysis revealed nodular changes of different sizes in the thymus, which consisted of a mixture of pleomorphic and spindle cells. The pleomorphic cells with distinct atypia were giant cells and multinucleated cells with large cell sizes and frequent nuclear divisions. The spindle cells were mild to moderate atypical and arranged in a woven pattern, and nuclear division was rare. Immunohistochemical analysis indicated that vimentin was diffusively expressed in tumor cells. No amplification was found in CDX2 and MDM4 genes using the FISH analysis. In conclusion, mediastinal thymus neoplasm should be considered in the presence of PUS and it is an exclusionary diagnosis based on clinical and pathological examination of the patient.

Undifferentiated Sarcoma: A Rare Tumor of the Prostate

Prostate cancer is the most common malignant tumor in men. The vast majority of prostate tumors are represented by prostatic adenocarcinomas (up to 95%). Sarcoma is a very rare tumor in adults with a formidable prognosis. Early diagnosis and radical surgery offer patients the best chance of a cure. We report the case of a 44-year-old patient with stage VI unresectable high-grade undifferentiated prostate sarcoma, initially presenting with urinary disorders and a large pelvic mass of prostatic origin, with normal Prostate-specific antigen (PSA) levels. The patient was managed by palliative chemotherapy.

Malignant undifferentiated epithelioid neoplasms with MAML2 rearrangements: A clinicopathologic study of seven cases demonstrating a heterogenous entity

Among mesenchymal tumors, MAML2 gene rearrangements have been described in a subset of composite hemangioendothelioma and myxoinflammatory fibroblastic sarcoma (MIFS). However, we have recently encountered MAML2-related fusions in a group of seven undifferentiated malignant epithelioid neoplasms that do not fit well to any established pathologic entities. The patients included five males and two female, aged 41-71 years old (median 65 years). The tumors involved the deep soft tissue of extremities (hip, knee, arm, hand), abdominal wall, and the retroperitoneum. Microscopically, the tumors consisted of solid sheets of atypical epithelioid to histiocytoid cells with abundant cytoplasm. Prominent mitotic activity and necrosis were present in 4 cases. In 3 cases, the cells displayed hyperchromatic nuclei or conspicuous macronucleoli, and were admixed with background histiocytoid cells and a lymphoplasmacytic infiltrate. By immunohistochemistry (IHC), the neoplastic cells had a nonspecific phenotype. On targeted RNA sequencing, MAML2 was the 3' partner and fused to YAP1 (4 cases), ARHGAP42 (2 cases), and ENDOD1 (1 case). Two cases with YAP1::MAML2 harbored concurrent RAF kinase fusions (RBMS3::RAF1 and AGK::BRAF, respectively). In 2 cases with targeted DNA sequencing, mutations in TP53, RB1 and PTEN were detected in 1 case, and PDGFRB mutations, CCNE1 amplifications and CDKN2A/2B deletion were detected in another case, which showed strong and diffuse PDGFRB expression by IHC. Of the 4 cases with detailed clinical history (median follow-up period 8 months), three developed distant metastatic disease (one of which died of disease); one case remained free of disease 3 years following surgical excision. In conclusion, we describe a heterogeneous series of MAML2-rearranged undifferentiated malignant epithelioid neoplasms, a subset of which may overlap with a recently described MIFS variant with YAP1::MAML2 fusions, further expanding the clinicopathologic spectrum of mesenchymal neoplasms with recurrent MAML2 gene rearrangements.

Primary Pancreatic Undifferentiated Pleomorphic Sarcoma

Primary pancreatic sarcomas are rare malignancies with an incidence of 0.1%. This case report is of a 48-year-old man who presented with this condition. The patient's treatment plan consisted of distal pancreatectomy and splenectomy with intraoperative immunohistochemistry and adjuvant chemotherapy. To correctly identify and treat undifferentiated pleomorphic sarcoma, a stepwise strategy involving cross-sectional imaging and extensive histopathology analysis is necessary.

Clinical and Pathologic Characterization of 94 Radiation-Associated Sarcomas: Our Institutional Experience

Radiation-associated sarcomas are an uncommon complication of therapeutic radiation. However, their prevalence has increased with the more widespread use of this treatment modality. The clinical, pathologic and genetic characteristics of radiation-associated sarcomas are not fully understood. In this study we describe the features of 94 radiation-associated sarcomas reviewed at our institution between 1993 and 2018, evaluate their overall survival (OS) and progression-free survival (PFS) outcomes, and compare them with their sporadic counterparts reviewed within the same time period. Histologic subtypes of all radiation-associated sarcomas included 31 (33%) undifferentiated sarcomas, 20 (21%) osteosarcomas, 17 (18%) angiosarcomas, 10 (11%) malignant peripheral nerve sheath tumor (MPNST), 9 (10%) leiomyosarcomas, 4 (4%) myxofibrosarcomas, and 3 (3%) rhabdomyosarcomas. Six patients had a documented cancer predisposition syndrome. The most common preceding neoplasms included adenocarcinoma (47%) and squamous cell carcinoma (19%), with a mean latency of 13 years. Multivariable Cox survival analysis demonstrated that advanced stage at diagnosis based on pT category (AJCC eighth edition) and fragmented resection were associated with worse survival outcomes. In addition, there was a statistically significant difference in PFS between radiation-associated undifferentiated sarcomas and MPNST when compared to their sporadic counterparts using the Kaplan-Meier method and Log-rank analysis. Overall, our study shows that radiation-associated sarcomas comprise a wide clinico-pathologic spectrum of disease, with a tendency for aggressive clinical behavior. This study further delineates the understanding of these uncommon diseases. Future studies are necessary to better understand the genetic and epigenetic changes that drive the differences in behavior between these tumors and their sporadic counterparts, and to offer better treatment options.

Undifferentiated embryonal sarcoma of the liver with epithelioid features in an adult patient: A case report

INTRODUCTION

Undifferentiated embryonal sarcoma of the liver (UESL) is a rare form of liver malignancy, with most cases reported in the pediatric population. This disease is extremely uncommon in adults. Herein, we report the first case of UESL with epithelioid features in an adult patient.

PATIENT CONCERNS

A 50-year-old man was admitted to our hospital due to epigastric pain.

DIAGNOSIS AND INTERVENTIONS

Computed tomography and magnetic resonance imaging revealed a space-occupying lesion in the right lobe of the liver. A right hemihepatectomy was performed. Postoperative pathological and immunohistochemical examinations confirmed the diagnosis of UESL and features of epithelioid differentiation.

OUTCOMES

The patient recovered well and refused adjuvant therapy. Unfortunately, the patient died of tumor recurrence 3 months after hospital discharge.

CONCLUSION

UESL is a rare form of liver cancer, with most cases reported in the pediatric population. This case study highlights an extremely uncommon case of UESL with epithelioid features and a very poor prognosis. The findings suggest that complete intraoperative resection and postoperative adjuvant therapy should be considered to improve the prognosis of adult patients with UESL with epithelioid features.

Oral histiocytic sarcoma in a cat with mandibular invasion and regional lymph node metastasis

Case summary

An 11-year-old female spayed domestic medium-hair cat presented for dental prophylaxis, at which time no oral mass was appreciated. Fifteen days after a dental cleaning, a mass expanding the oral mucosa of the rostral mandible was identified. An incisional biopsy revealed that the oral mucosa was infiltrated by neoplastic round-to-spindloid mesenchymal cells arranged in streams and small, dense aggregates consistent with an undifferentiated sarcoma. The patient was managed medically for approximately 6 months following the diagnosis, but, owing to declining health, euthanasia was elected and a post-mortem examination was performed. On post-mortem examination, the previously described neoplastic cells were infiltrating the rostral mandible and had metastasized to the right submandibular lymph node. Immunohistochemistry performed during the postmortem examination found that neoplastic cells were positive for Iba-1, CD18 and CD204, and negative for MUM-1, S100, Melan-A and E-cadherin, favoring a diagnosis of oral histiocytic sarcoma. Although recently recognized in cats, feline oral histiocytic sarcoma is rare, the tumor’s immunohistochemical profile is unstandardized, and the tumor’s behavior and prognosis are unclear. The diagnosis is challenging if small incisional biopsies are submitted and the neoplasm is poorly differentiated. This case report discusses the clinical, macroscopic, microscopic and immunohistochemical features of oral histiocytic sarcoma in a cat with mandibular invasion and submandibular lymph node metastasis.

Relevance and novel information

Feline primary oral histiocytic sarcoma is rare and tumor behavior and prognosis are unclear. This report broadens the immunohistochemical features of the tumor and recognizes mandibular invasion and submandibular lymph node metastasis.

Tumor Embolism as a Cause of Renal Artery Occlusion and Acute Kidney Injury Diagnosed and Treated with Endovascular Intervention in a Patient with Mediastinal Undifferentiated Sarcoma

A 72-year-old man presented with back pain due to a mass in the left posterior mediastinum that had surrounded and partly infiltrated the descending aorta. Mediastinal undifferentiated sarcoma was diagnosed. After the diagnosis, sudden anuria was observed. Contrast-enhanced computed tomography revealed an enhancement defect at the origins of the bilateral renal arteries. He received catheter-directed thrombolysis and was weaned off dialysis. The aspirated artery thrombus contained tumor cells, proving our diagnosis of acute kidney injury secondary to bilateral renal artery tumor embolism. In cancer patients, endovascular intervention may be a useful diagnostic and therapeutic option in cases of acute kidney injury secondary caused by peripheral thromboembolic complications.

Transformed Canine and Murine Mesenchymal Stem Cells as a Model for Sarcoma with Complex Genomics

Simple Summary

Sarcomas are rare cancers of mesenchymal origin, the majority of which are characterized by many copy number alterations, amplifications, or deletions. Because of these complex genomics, it is notoriously difficult to identify driver events of malignant transformation. In this study, we show that murine and canine mesenchymal stem cells (MSCs) can be used to model spontaneous malignant transformation towards sarcomas with complex genomics. We show that these MSCs have an abnormal karyotype, many structural variants, and point mutations at whole genome sequencing analysis, and form sarcomas after injection into mice. Our cross-species analysis reveals that p53 loss is an early event in sarcomagenesis, and it was shown that MSCs with a knock-out in Trp53 transform earlier compared to wild-type MSCs. Our study points to the importance of p53 loss in the transformation process towards sarcomas with complex genomics.

Abstract

Sarcomas are rare mesenchymal tumors with a broad histological spectrum, but they can be divided into two groups based on molecular pathology: sarcomas with simple or complex genomics. Tumors with complex genomics can have aneuploidy and copy number gains and losses, which hampers the detection of early, initiating events in tumorigenesis. Often, no benign precursors are known, which is why good models are essential. The mesenchymal stem cell (MSC) is the presumed cell of origin of sarcoma. In this study, MSCs of murine and canine origin are used as a model to identify driver events for sarcomas with complex genomic alterations as they transform spontaneously after long-term culture. All transformed murine but not canine MSCs formed sarcomas after subcutaneous injection in mice. Using whole genome sequencing, spontaneously transformed murine and canine MSCs displayed a complex karyotype with aneuploidy, point mutations, structural variants, inter-chromosomal translocations, and copy number gains and losses. Cross-species analysis revealed that point mutations in Tp53/Trp53 are common in transformed murine and canine MSCs. Murine MSCs with a cre-recombinase induced deletion of exon 2–10 of Trp53 transformed earlier compared to wild-type murine MSCs, confirming the contribution of loss of p53 to spontaneous transformation. Our comparative approach using transformed murine and canine MSCs points to a crucial role for p53 loss in the formation of sarcomas with complex genomics.

Congenital Suborbital Undifferentiated Sarcoma in a Crossbred Calf

Simple Summary

Congenital tumours are rare conditions in both veterinary and human medicine. Undifferentiated sarcomas represent a recently introduced section that encompasses unclassified sarcomas that have no distinct histologic, immunohistochemical, or genetic features. The aim of this study is to describe the clinical and pathological phenotype of a 3-day-old male crossbred calf presenting a congenital suborbital mass that infiltrated the underlying muscle and bone, and suggestive of undifferentiated sarcoma. To the best of our knowledge, our report constitutes the first clinical, ultrasonographic, radiographic, endoscopic and pathological study of a congenital undifferentiated sarcoma, a condition that has been rarely reported in the veterinary literature.

Abstract

Undifferentiated sarcomas are rare conditions that represent a group of unclassified sarcomas. The purpose of this study is to describe the clinical and pathological features of a calf showing a congenital infiltrating suborbital mass suggestive of undifferentiated sarcoma. The animal was referred because of respiratory distress and the presence of a right suborbital mass since birth. At ultrasonography, the mass displayed an irregular shape with multiple cavities. Radiographs revealed a diffuse, poorly defined mass with different densities overlying the bony structures of the skull. Endoscopy showed a co-involution of the mass in the right side with extension into the nasopharynx. Post-mortem examination showed a round, poorly demarcated neoplasia infiltrating the nasal turbinate and displacing the nasal septum. Histologically, the subcutis was expanded by lobules and bundles of densely cellular neoplastic spindle cells. The neoplasm infiltrated the underlying muscles, bone and the right retromandibular lymph node. The neoplastic cells had a diffuse intense cytoplasmic immunexpression to vimentin, and were negative to cytokeratin AE1/AE3, desmin, MUM1, IBA1, melan A, chromogranin and synaptophysin.

Oral histiocytic sarcoma in a cat

Case summary

A 15-year-old neutered male domestic shorthair cat presented with a 4-week history of dysphonia and reluctance to chew hard food. Oral examination revealed a mass lesion on the caudal soft palate. Biopsy was performed and histopathology with immunohistochemistry was most consistent with histiocytic sarcoma. CT of the head identified a discrete, left-sided, soft tissue mass lesion cranial to the tonsil with bilaterally symmetrical regional lymph nodes. CT of the thorax was unremarkable. Surgical removal achieved cytoreduction but not complete removal. Adjuvant chemotherapy with lomustine 10 mg (30 mg/m²) was initiated. The patient developed suspected pancreatitis 2–3 weeks postoperatively, so further chemotherapy treatment was discontinued, but supportive treatment with pain relief and appetite stimulants was provided. Three months postoperatively, the patient developed recurrent dysphonia, and oral examination revealed a suspicion of local recurrence. Confirmation of diagnosis (cytopathology or histopathology) was not obtained. Supportive treatment to maintain a good quality of life was continued and the patient was euthanased 6 months after diagnosis owing to progressive disease.

Relevance and novel information

Only a few reports have been published describing histiocytic diseases of cats. To our knowledge, this is the first report of a feline histiocytic sarcoma of the oral cavity. Therefore, histiocytic sarcoma should be considered as a differential diagnosis in feline patients with an oral mass, especially if histopathology suggests a pleomorphic and poorly differentiated sarcoma. Immunohistochemistry for the confirmation of cell line origin would be strongly recommended.

DNA Methylation Profiling for Diagnosing Undifferentiated Sarcoma with Capicua Transcriptional Receptor (CIC) Alterations

Undifferentiated soft tissue sarcomas are a group of diagnostically challenging tumors in the pediatric population. Molecular techniques are instrumental for the categorization and differential diagnosis of these tumors. A subgroup of recently identified soft tissue sarcomas with undifferentiated round cell morphology was characterized by Capicua transcriptional receptor (CIC) rearrangements. Recently, an array-based DNA methylation analysis of undifferentiated tumors with small blue round cell histology was shown to provide a highly robust and reproducible approach for precisely classifying this diagnostically challenging group of tumors. We describe the case of an undifferentiated sarcoma of the abdominal wall in a 12-year-old girl. The patient presented with a voluminous mass of the abdominal wall, and multiple micro-nodules in the right lung. The tumor was unclassifiable with current immunohistochemical and molecular approaches. However, DNA methylation profiling allowed us to classify this neoplasia as small blue round cell tumor with CIC alterations. The patient was treated with neoadjuvant chemotherapy followed by complete surgical resection and adjuvant chemotherapy. After 22 months, the patient is disease-free and in good clinical condition. To put our experience in context, we conducted a literature review, analyzing current knowledge and state-of-the-art diagnosis, prognosis, and clinical management of CIC rearranged sarcomas. Our findings further support the use of DNA methylation profiling as an important tool to improve diagnosis of non-Ewing small round cell tumors.

Spontaneous pancreatic undifferentiated pleomorphic sarcoma in a laboratory rat: A case report

We present a case of spontaneous undifferentiated/unclassified sarcoma, of a pleomorphic subtype formerly known as malignant fibrous histiocytoma (UPS/MFH), arising from the pancreas of a laboratory rat. The mass was excised after laparotomy from a 6-month-old female laboratory Wistar rat. It presented a giant multilobulated mass of irregular shape, which had arisen from the pancreas and occupied almost the entire peritoneal cavity. Histologically the tumor was characterized by a highly variable morphological pattern, with frequent transitions from storiform to pleomorphic areas. An extensive immunohistochemical examination revealed no specific lines of differentiation. Immunohistochemical positivity was observed only to MIB-1 (high Ki-67 proliferation index), vimentin and CD68 antibodies. The diagnosis was compatible with UPS/MFH. To the best of our knowledge, the present case is the first report of a spontaneous primary UPS/MFH arising from the pancreas of a laboratory rat.

Undifferentiated sarcoma of the soft tissues with cystic degeneration: Case report and review of literature

Undifferentiated sarcoma (UNDS) of the soft tissue is an exceedingly rare disease. Its diagnosis depends mainly on molecular and immunohistochemical analyses to exclude other soft-tissue sarcomas. It is difficult to confirm a positive diagnosis by imaging pathological features because of their rarity and similarity with other conditions. Since 2013, only 13 cases of undifferentiated soft-tissue sarcoma, mostly diagnosed through imaging of solid tumors in infant and children, have been reported. The authors present a rare case of a 3-month-old Chinese boy with UNDS primarily in the left lower extremity and characterized by a cystic and solid growth pattern.

An undifferentiated sarcoma with BCOR-CCNB3 fusion transcript - pathological and clinical retrospective study

The BCOR-CCNB3 positive sarcoma is a recently identified sarcoma morphologically and clinically similar to Ewing sarcoma in adolescents and young adults. The BCOR-CCNB3 fusion transcript originates from a paracentric inversion on the X chromosome with an in-frame fusion between the last codon of BCOR and the exon 5 of CCNB3 gene. We report morphological and molecular genetic analysis of 8 undifferentiated sarcomas positive for the BCOR-CCNB3 fusion. Six of the eight BCOR-CCNB3 positive sarcoma patients were male. Five of the eight patients were in their second decade of life (median of all patients 14 years at diagnosis). The bone marrow involvement was demonstrated in 2 of 4 patients tested. Detection of the fusion transcripts BCOR-CCNB3 in the bone marrow suggests that patients with positive findings are at high risk of the tumor progression.

Application of adipocyte-related antibodies in undifferentiated sarcomas to identify dedifferentiated liposarcomas based on histological and clinical analysis

BACKGROUND

Due to morphologic similarities between undifferentiated sarcoma (US) and dedifferentiated liposarcoma (DDLPS), some portions of US could be identified as DDLPS. In this study, we applied adipocyte-related antibodies in order to discriminate possible cases of DDLPS from US.

MATERIALS AND METHODS

A total of 46 cases, previously diagnosed as US, were examined. Immunohistochemistry for MDM2, CDK4, calreticulin, FABP4, and stathmin were performed. Histological findings were reviewed and clinical data was analyzed retrospectively.

RESULTS

MDM2, CDK4, calreticulin, FABP4, and stathmin were positive in 17 (37.0%), 14 (30.4%), 3 (6.5%), 1 (2.2%), and 12 (26.1%) of the total 46 cases, respectively. MDM2/CDK4 positive cases showed more frequent positivity for calreticulin/FABP4/stathmin. Survival analysis, based on staining pattern, revealed a significantly better survival in the group where either MDM2 and CDK4 were positive and at least one of calreticulin, FABP4, or stathmin staining were positive.

CONCLUSIONS

We conclude that when either MDM2-positive or CDK4-positive cases show any other positive results for calreticulin, FABP4, or stathmin, they have a significantly better survival and the possibility of DDLPS should be considered. Additional use of calreticulin, FABP4, or stathmin immunohistochemistry helps us to narrow the pool for further studies such as molecular analysis for a definite diagnosis.

Primary Spinal Epidural CIC-DUX4 Undifferentiated Sarcoma in a Child

Primitive round- or spindle-cell EWSR1-negative undifferentiated sarcomas harboring CIC-DUX4 gene fusion are the most common form of Ewing-like sarcomas. These tumors primarily occur in peripheral soft tissues, but examples have been described within viscera and the brain. As far as we are aware, CIC-DUX4 positive primary epidural spinal sarcoma has not been reported. Herein, we describe a T5-T6 epidural tumor in a 15-year-old girl in which many neoplastic cells had moderate and focally abundant cytoplasm, including plasmacytoid or rhabdoid cells, rather than the more common Ewing-like morphology described in the majority of such tumors. The diagnosis was confirmed by fluorescent in situ hybridization after the tumor was found to be WT-1 positive, and comprehensive genomic profiling demonstrated breakpoints in exon 20 and exon 1 of the CIC and DUX4 genes, respectively. After treatment with local radiation and systemic chemotherapy, resected recurrent tumor demonstrated more pleomorphic neoplastic cells as well as intracytoplasmic eosinophilic globules and nuclear pseudoinclusions which may reflect therapy-related changes. Unfortunately, there was further progression of tumor including the development of intracranial lesions, and the patient succumbed to her tumor 22 months after the original resection.

BCOR-CCNB3 Undifferentiated Sarcoma-Does Immunohistochemistry Help in the Identification?

Recent methodology has enabled the identification of some new genetic subgroups within the melting pot of lesions presently classified by the 2013 WHO classification as "undifferentiated/unclassified sarcomas". One of these subgroups is characterized by a paracentric inversion of the X chromosome with consequent formation of a BCOR-CCNB3 fusion. Clinical and pathological features of these tumors overlap with the Ewing sarcoma family as well as other soft tissue sarcomas, thus making them difficult to diagnose. To investigate the morphological and immunohistochemical characteristics of BCOR-CCNB3 positive sarcoma, we reviewed two sarcoma series, comprising 632 and 121 cases. The 11 tumors harboring the BCOR-CCNB3 fusion, identified by CCNB3 immunohistochemistry and/or RT-PCR, were reevaluated for morphological characteristics and further immunohistochemical investigations for CCNB3, SATB2, and Pax8 were performed. Tumors harboring a BCOR-CCNB3 fusion (11/753) occured exclusively in males, with a mean age at diagnosis of 12.9 years, and were mainly axially located. In this group of either spindled or round cell tumors, vesicular nuclei with finely dispersed chromatin, inconspicuous nucleoli and an arciform vascular pattern were pathognomonic. More than 50% of cases stained positive for SATB2 and Pax8, raising the hypothesis of a potential use of these markers in the identification of BCOR-CCNB3 positive undifferentiated/unclassified sarcomas. CCNB3 was confirmed as a useful ancillary immunohistochemical marker.

Uterine sarcoma Part II-Uterine endometrial stromal sarcoma: The TAG systematic review. Taiwan J Obstet Gynecol. 2016;55:472-479. [PMID: 27590366 DOI: 10.1016/j.tjog.2016.04.034]

Endometrial stromal tumors are rare uterine tumors (<1%). Four main categories include endometrial stromal nodule, low-grade endometrial stromal sarcoma (LG-ESS), high-grade endometrial stromal sarcoma (HG-ESS), and uterine undifferentiated sarcoma (UUS). This review is a series of articles discussing the uterine sarcomas. LG-ESS, a hormone-dependent tumor harboring chromosomal rearrangement, is an indolent tumor with a favorable prognosis, but characterized by late recurrences even in patients with Stage I disease, suggesting the requirement of a long-term follow-up. Patients with HG-ESS, based on the identification of YWHAE-NUTM2A/B (YWHAE-FAM22A/B) gene fusion, typically present with advanced stage diseases and frequently have recurrences, usually within a few years after initial surgery. UUS is, a high-grade sarcoma, extremely rare, lacking a specific line of differentiation, which is a diagnosis of exclusion (the wastebasket category, which fails to fulfill the morphological and immunohistochemical criteria of translocation-positive ESS). Surgery is the main strategy in the management of uterine sarcoma. Due to rarity, complex biological characteristics, and unknown etiology and risk factors of uterine sarcomas, the role of adjuvant therapy is not clear. Only LG-ESS might respond to progestins or aromatase inhibitors.

Subarachnoid hemorrhage caused by an undifferentiated sarcoma of the sellar region

Background:

It is rare for patients with pituitary apoplexy to exhibit concomitant subarachnoid hemorrhage (SAH). Only a handful of patients with pituitary apoplexy have developed such hemorrhagic complications, and histopathological examination revealed pituitary adenoma as the cause of SAH.

Case Report:

A previously healthy 35-year-old woman was brought to our institution after complaining of severe headache and left monocular blindness. Brain computed tomography showed a diffuse SAH with a central low density. Subsequently, the brain magnetic resonance imaging revealed an intrasellar mass with heterogeneous contrast enhancement. The patient was presumptively diagnosed with SAH secondary to hemorrhagic pituitary adenoma and underwent transcranial surgery to remove both the tumor and subarachnoid clot. A histological evaluation of the surgical specimen revealed malignant cells with strong predilection for vascular invasion. Following immunohistochemical evaluation, the tumor was negative for the majority of tumor markers and was positive only for vimentin and p53; thus, a diagnosis of undifferentiated sarcoma was established.

Conclusions:

This case was informative in the respect that tumors other than pituitary adenoma should be included in the differential diagnosis of patients with pituitary apoplexy.

Primary Renal Rhabdomyosarcoma: An Unusual Bone Metastasizing Tumor of Kidney

Rhabdomyosarcoma (RMS) is one of the common malignant tumors in the pediatric age group. There is only a single case report of primary renal alveolar RMS. Fine needle aspiration (FNA) findings of primary renal RMS has not been reported so far. Hence we present an unusual case of primary alveolar RMS of the kidney. An 11 year old boy presented with an abdominal mass. On FNA a diagnosis of undifferentiated sarcoma and anaplastic Wilms tumor were considered. The tumor was resected and showed histopathological features of alveolar rhabdomyosarcoma. He developed multiple bony metastases and succumbed to the illness despite aggressive chemotherapy. RMS of the kidney should be considered in the differential diagnosis of children with a renal mass, and may have an aggressive clinical course with bone metastases.

The Evolution of Pediatric Soft Tissue Sarcoma Classification in the Last 50 Years

This review discusses the history of the classification of soft tissue sarcomas in children and adolescents, the current transition toward integration of morphology and molecular genetics as new entities emerge, and future perspectives.

Interleukin-8-producing primary cardiac undifferentiated sarcoma in a child with sustained fever

We report the case of a 12-year-old boy with primary undifferentiated sarcoma of the left atrium. He had sustained fever during the clinical course and multiple lung and brain metastases. Chemotherapy and irradiation were ineffective; he died 41 days after hospitalization. On retrospective analysis, interleukin-8 (IL-8) was elevated; this was supported by immunohistochemistry and gene expression analysis of tumor samples. IL-8 continued to increase with tumor progression accompanied by elevated neutrophil count and C-reactive protein. IL-8 is involved in malignant tumor proliferation, migration, and angiogenesis and may have been related to the clinical condition and prognosis in the present case.

Undifferentiated sarcoma of the liver: a case study of an erythropoietin-secreting tumor

Undifferentiated embryonal sarcoma of the liver (UESL) is an uncommon hepatic tumor usually found in children, with rare cases reported in adults. We present a case of a 53-year-old woman with an undifferentiated sarcoma of the liver (USL), which resembles UESL, who initially presented with a markedly elevated hematocrit (61.2%). Cytogenetic studies for polycythemia vera were negative, but the patient's erythropoietin (EPO) was elevated. A computed tomography scan and subsequent partial hepatectomy revealed a well-circumscribed, partially cystic mass in the right lobe of the liver measuring 34 cm. Following surgery, the patient's EPO level and hematocrit dropped to within normal range and remained so for 1 year, at which point it rose again. A subsequent magnetic resonance imaging scan showed a liver mass at the previous resection margin, consistent with a recurrence. In this case study, we describe the first reported USL resembling an UESL that secretes EPO, which was a useful marker of tumor recurrence.

Undifferentiated round cell sarcoma of the broad ligament

Sarcomas of the broad ligament are very uncommon. To our knowledge, there are no cases published of undifferentiated round cell sarcoma of the broad ligament. Round cell sarcomas are a rare and very aggressive variant, which due to their sensitivity to chemotherapy, have an acceptable prognosis. We report the case of a 27-year-old woman who presented with a pelvic mass with a 7-cm diameter placed on the right broad ligament. After surgery, she was diagnosed with undifferentiated round cell sarcoma of the broad ligament. The patient received adjuvant chemotherapy and radiotherapy, and after 12 years of follow-up, she still remains asymptomatic. Proper differential diagnoses as well as an appropriate adjuvant therapy after surgical treatment seem to be essential to obtain good oncological outcomes in this rare entity.

Hedgehog pathway activity in pediatric embryonal rhabdomyosarcoma and undifferentiated sarcoma: a report from the Children's Oncology Group

BACKGROUND

Aberrant activation of the hedgehog (Hh) signaling pathway is implicated widely in both pediatric and adult malignancies. Inactivation of the Hh regulator PTCH is responsible for the Gorlin cancer predisposition syndrome. The spectrum of tumors found in Gorlin Syndrome includes basal cell carcinoma, medulloblastoma, and rarely, rhabdomyosarcoma (RMS). A previous report utilizing in situ hybridization has provided initial evidence for the expression of Hh targets GLI1 and PTCH in RMS tumors.

PROCEDURE

To investigate the role of Hh pathway signaling in pediatric RMS and undifferentiated sarcoma (US) tumors, the expression of Hh pathway targets GLI1 and PTCH was measured. RNA was extracted from archival human tumor specimens collected from pediatric patients enrolled on Intergroup Rhabdomyosarcoma Study III and IV, and subjected to quantitative reverse transcriptase-polymerase chain reaction.

RESULTS

Expression of GLI1 with or without PTCH was detected in substantial subsets of embryonal RMS (ERMS) and US tumors but only rarely in alveolar RMS tumors. Neither PTCH mutations nor activating SMO mutations were detected in ERMS tumors with high GLI1 expression. Microarray analysis demonstrated relative overexpression of downstream Hh targets in ERMS tumors with high or intermediate GLI1 expression. Unlike a recent report, Hh pathway activity in ERMS tumors did not correlate with a unique clinical phenotype.

CONCLUSIONS

Our findings support a role for Hh pathway activation in the genesis of a subset of ERMS and US tumors. Hh signaling may represent a novel therapeutic target in affected tumors.

Undifferentiated Sarcoma of the Salivary Gland in a Mongolian Gerbil (Meriones unguiculatus)

A subcutaneous mass was found in the lower ventral neck region of a 55-week-old male Mongolian gerbil (Meriones unguiculatus). Histopathologically, the mass involved salivary glands and featured diffuse proliferation of pleomorphic neoplastic cells with large necrotic foci. The lesion was well demarcated from the surrounding tissue, although invasive growth to fibrous septa was occasionally observed. The neoplastic cells were mainly arranged in irregular sheets with severe cellular atypia, round to oval nuclei and varying amounts of eosinophilic cytoplasm. Mitotic figures and multinucleated giant cells were frequent. Immunohistochemical analysis revealed that the neoplastic cells were strongly positive for vimentin and S-100 and negative for NSE, cytokeratin, α-SMA, c-kit, factor VIII, CD34, α-1-antitrypsin, lysozyme and MSR-A. Based on the results, the mass was diagnosed as an undifferentiated sarcoma of the salivary gland. To the best of our knowledge, this is the first report of such a tumor in Mongolian gerbils.

Loss of INI1 expression defines a unique subset of pediatric undifferentiated soft tissue sarcomas

Malignant rhabdoid tumor has traditionally been defined by its histologic phenotype. However, genetic investigations of malignant rhabdoid tumor have revealed a characteristic loss of or mutation in the INI1 gene on chromosome 22q. The occurrence and significance of soft tissue tumors meeting genetic criteria for malignant rhabdoid tumor but with an undifferentiated non-rhabdoid histology is poorly characterized. Seventeen undifferentiated sarcomas, lacking rhabdoid histology were identified either through the surgical pathology files of The Children's Hospital of Philadelphia (1980-2005) or in consultation. Immunohistochemistry for the INI1 protein showed a loss of nuclear expression within tumor cells in five of these cases. On histologic review, these five tumors had a featureless sheet-like architecture; four were small round blue cell tumors, and one showed focal spindling. Although they had variably prominent nucleoli, classic rhabdoid morphologic features were not identified in any of these cases at primary presentation. Additional immunohistochemistry showed a polyphenotypic profile. Four of the five tumors showed genetic abnormalities involving the INI1 gene by a combination of fluorescent in situ hybridization, reverse transcription-polymerase chain reaction, and/or mutational analysis. Patient ages ranged from 1 week to 5 years. Four patients were male, and one was female. Sites included two neck tumors, two extremity tumors, and one paraspinal tumor. Two patients are alive and well over 15 years from the time of diagnosis; the remaining four are alive and well but with less than 2 years follow-up. Thus, alterations of the INI1 gene with consequent loss of expression identified a population of undifferentiated sarcomas lacking classic rhabdoid morphology in young patients, with evidence of favorable survival. Whether these undifferentiated sarcomas represent a clinicopathologic entity distinct from classic malignant rhabdoid tumor requires further investigation.