Treatment of infantile fibrosarcoma with chemotherapy and surgery: results from the Dana-Farber Cancer Institute and Children's Hospital, Boston

Larotrectinib versus historical standard of care in patients with infantile fibrosarcoma: protocol of EPI-VITRAKVI

The EPI VITRAKVI study is a retrospective study designed to place the results of the single-arm Phase I/II larotrectinib SCOUT trial into context by comparison with external historical controls. Its primary objective is to compare the time to medical treatment failure between larotrectinib and the historical standard of care (chemotherapy) in patients with infantile fibrosarcoma. External historical cohorts have been selected by using objective criteria. The Inverse Probability of Treatment Weighting method will be used to adjust for potential confounding. The current publication illustrates how an external control arm study can complement data from a single-arm trial and addresses uncertainties encountered in the assessment of therapies targeting rare abnormalities where randomized controlled trials are considered not feasible. Clinical Trial Registration: NCT05236257 (ClinicalTrials.gov).

Case report: A rare case of congenital non-metastatic low-grade fibrosarcoma of the pleura in a 6-month-old infant manifested as pneumonia

Introduction and importance

Congenital Infantile fibrosarcoma is a rare tumor in children and accounts for only 10 % of various malignant tumors in this age group. Manifestations vary according to the site of occurrence. Symptoms of the tumor located in unusual places can be misleading and obscure the actual diagnosis, which in turn may waste precious effort and time until the correct diagnosis is established. Infant malignancies should be considered to reduce the morbidity and mortality associated with this pathology.

Case presentation

We present the case of a 6-month-old infant, who was admitted to our hospital with a one-month history of high fever and dry cough, with no improvement in symptoms after treatment with antibiotics. Computed tomography showed a heterogeneous mass in the pleural cavity compressing the lung tissue, in addition to bilateral mild pleural effusion. Thoracotomy was indicated and the tumor was completely resected.

Clinical discussion

Histopathological and Immunohistochemical approach is crucial because this type of tumor can overlap with many soft tissue sarcomas. After searching in medical literature, no published evidence of a similar case was found, and thus we managed the patient empirically, depending on the usual approach for congenital fibrosarcoma. Complete surgical resection is the golden standard of treatment, followed by chemotherapy depending on pathological findings.

Conclusion

Clinical awareness is important in any unresponsive pneumonia and malignancies should be taken into consideration.

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Congenital infantile fibrosarcoma (CIFS) is a rare tumor and is often seen after birth and evolve during the early years of life.

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CIFS can manifest in several places in the body but rarely in chest cavity.

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Immunohistochemistry is a significant assistant in the diagnosis of soft tissue neoplasms.

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Complete surgical resection is the golden standard in treatment followed by chemotherapy depending on pathological findings.

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Local recurrence is a common phenomenon and occurs in 20–40 % of cases.

Radical Resection of Pediatric Fibrosarcoma Is Not Associated With Survival Benefit: A Nationwide Database Analysis

INTRODUCTION

Fibrosarcoma is one of the most common nonrhabdomyosarcoma soft tissue sarcomas in the pediatric population. Surgical resection is the cornerstone of treatment; however, optimal factors regarding the extent of fibrosarcoma resection in localized versus regional disease is poorly understood.

METHODS

The Surveillance, Epidemiology, and End Results database was queried for patients who are 19 y old or younger with a diagnosis of fibrosarcoma from 1975 to 2016. Kaplan-Meier analyses were performed for disease-specific survival on clinical and pathologic variables. Multivariate analysis was performed based on significant predictors of disease-specific survival.

RESULTS

There were 1290 patients (median age 13 [7-17] y) identified with fibrosarcoma. The overall survival rate at 20 y was 93%. Radical resection was performed on 22%, 40%, and 52% of patients with localized, regional, and distant Surveillance, Epidemiology, and End Results disease stage, respectively. Chemotherapy (P < 0.001), radiation (P < 0.001), histology (P < 0.001), and stage (P = 0.004) were significant predictors of increased mortality using univariate Kaplan-Meier analysis. Most patients (86%) with localized or regional stage who underwent radiation had fibrosarcomas of nondermatofibrosarcoma histology (P < 0.001). Dermatofibrosarcoma subtype comprised most radical resections (41%). Excluding distant stage, nondermatofibroma histology (hazard ratio 16.94, 95% confidence interval 3.77-76.01) and regional stage (hazard ratio 8.15, 95% confidence interval 2.93-22.69) were independent prognostic factors of mortality (both P < 0.001). Radical resection was not a significant independent prognostic indicator of survival.

CONCLUSIONS

Nondermatofibrosarcoma subtype is independently associated with increased mortality. Although surgery remains the mainstay of treatment, the extent of resection is not a predictor of survival for patients with the localized and regional stage of disease.

Non-rhabdomyosarcoma soft tissue sarcomas diagnosed in patients at a young age. An overview of clinical, pathological, and molecular findings

OBJECTIVE

Disease spectrum in pediatric sarcoma differs substantially from adults. We report a cohort of very young children with non-rhabdomyosarcoma soft tissue sarcoma (NRSTS) detailing their molecular features, treatment, and outcome.

METHODS

We report features of consecutive children (age <2 years) with NRSTS (2000-2017). Archival pathological material was re-reviewed, with additional molecular techniques applied where indicated.

RESULTS

Twenty-nine patients (16 females, 55%) were identified (median age 6 months; range 0-23). Most common diagnoses included infantile fibrosarcoma (IFS, n = 14, 48%), malignant rhabdoid tumor (MRT, n = 4, 14%), and undifferentiated sarcoma (n = 4, 14%). Twenty-seven of 29 (93%) had tumor molecular characterization to confirm diagnosis. Clinical presentation included a swelling/mass (n = 23, 79%). Disease extent was localized (n = 20, 69%), locoregional (n = 6, 21%), or metastatic (n = 3, 10%). Seventeen of 29 (59%) who underwent surgery achieved complete resection (R0). Other treatments included conventional chemotherapy (n = 26, 90%), molecularly targeted therapies (n = 3, 10%), and radiation (n = 5, 17%). At last follow-up (median 3 years; range 0.3-16.4), 23 (79%) were alive, disease-free and six (21%) had died of disease. All patients with IFS were alive and all those with MRT died. A cancer predisposition syndrome (CPS) was confirmed in three of 10 (30%) genetically tested patients.

CONCLUSION

We recommend tumor molecular characterization in all young patients including evaluation for CPS to optimize treatment options and prognostication.

Differential diagnostic features between congenital haemangioma, KHE, and congenital fibrosarcoma: a single-centre experience

Congenital haemangioma (CH) is a rare benign vascular tumour presenting at birth with excellent prognosis. Usually, CH regresses without treatment within the first few months of life. Kaposiform Haemangioendothelioma (KHE) is another type of vascular tumours that has been described as benign with locally aggressive potential. Although the diagnosis of vascular tumours is usually straightforward based on typical clinical presentation, yet some confusing similarities may exist with congenital sarcomas.Conclusion: Data of cases managed at the vascular anomaly clinic during the period 2015 through 2019 were retrospectively analysed. The study included three groups of patients: cases diagnosed as congenital haemangioma (9 cases), cases of Kaposiform Haemangioendothelioma who presented in the neonatal period (7 cases), as well as cases of congenital fibrosarcoma (4 cases) that were referred to the vascular anomaly clinic because of apparent similarity with vascular tumours. The hallmark of the study was to compare clinical and imaging features in the three groups to facilitate differentiation and remove diagnostic confusion when managing these rare cases in the future. What is Known: • Congenital haemangioma is a rare benign vascular tumour presenting at birth. • Kaposiform Haemangioendothelioma is another type of vascular tumours that has been described as benign with locally aggressive potential. What is New: • Confusing similarities may exist between vascular tumours and congenital sarcomas.

Advances in the Diagnosis and Management of Neonatal Sarcomas

Neonatal sarcomas comprise a heterogeneous group of rare soft tissue neoplasms that present unique diagnostic and therapeutic challenges. Recent advances in molecular profiling have improved diagnostic capabilities and reveal novel therapeutic targets. Clinical trials demonstrate differences in behavior between sarcoma subtypes that allow for better clinical management. Surgical resection has been replaced with a multimodal approach that includes chemotherapy and radiotherapy. Despite these advances, neonates with sarcoma continue to fare worse than histologically similar sarcomas in older children, likely reflecting differences in tumor biology and the complexities of neonatal medicine. This review focuses on recent advances in managing neonatal sarcomas.

Canadian Consensus for Biomarker Testing and Treatment of TRK Fusion Cancer in Pediatric Patients

Neurotrophic tyrosine receptor kinase gene fusions (NTRK) are oncogenic drivers present at a low frequency in most tumour types (<5%), and at a higher frequency (>80%) in a small number of rare tumours (e.g., infantile fibrosarcoma [IFS]) and considered mutually exclusive with other common oncogenic drivers. Health Canada recently approved two tyrosine receptor kinase (TRK) inhibitors, larotrectinib (for adults and children) and entrectinib (for adults), for the treatment of solid tumours harbouring NTRK gene fusions. In Phase I/II trials, these TRK inhibitors have demonstrated promising overall response rates and tolerability in patients with TRK fusion cancer who have exhausted other treatment options. In these studies, children appear to have similar responses and tolerability to adults. In this report, we provide a Canadian consensus on when and how to test for NTRK gene fusions and when to consider treatment with a TRK inhibitor for pediatric patients with solid tumours. We focus on three pediatric tumour types: non-rhabdomyosarcoma soft tissue sarcoma/unspecified spindle cell tumours including IFS, differentiated thyroid carcinoma, and glioma. We also propose a tumour-agnostic consensus based on the probability of the tumour harbouring an NTRK gene fusion. For children with locally advanced or metastatic TRK fusion cancer who have either failed upfront therapy or lack satisfactory treatment options, TRK inhibitor therapy should be considered.

Unusual Case of Concurrent Retroperitoneal Congenital Infantile Fibrosarcoma and Cellular Type Congenital Mesoblastic Nephroma

BACKGROUND

Although congenital infantile fibrosarcoma (cIFS) is a rare soft tissue sarcoma among children, it constitutes one of the most common soft tissue sarcomas during the first year of life. Congenital mesoblastic nephroma (CMN) is the most common benign renal tumor usually developing during the first 3 months of life. cIFS and cellular type CMN (cCMN) share not only similar histopathologic features but identical molecular genetic abnormality including the ETV6/NTRK3 fusion gene. Here, we report an unusual case of cIFS occurring with cCMN.

CASE PRESENTATION

An 18-month-old girl presented with a 1-month history of abdominal distension and a few days' history of a palpable abdominal mass. A large heterogenous mass sized 9.0×11.2×11.6 cm on the right side of the abdomen and an isolated heterogenous lesion sized 4×4.5 cm within the right kidney were noted from the imaging study. Pathologic findings were consistent with cIFS and cCMN of the right kidney. In addition, both pathologic specimens contained the ETV6/NTRK3 fusion gene.

CONCLUSION

Although cIFS and cCMN share similar histopathologic features and molecular genetic abnormality, simultaneous occurrence of these 2 types of tumor is exceedingly rare. To our knowledge, this is the first unusual case report of concurrent cIFS and cCMN.

A newborn with a large NTRK fusion positive infantile fibrosarcoma successfully treated with larotrectinib

Infantile fibrosarcoma (IFS) is a rare pediatric cancer that typically presents early in life. Surgical resection is commonly curative; however, resection is sometimes not possible requiring additional multimodal treatment. IFS commonly harbors a fusion in one of the neurotrophic receptor tyrosine kinase (NTRK) genes. Larotrectinib, a highly selective inhibitor of tropomyosin receptor kinase (TRK), has been shown to be well tolerated and effective in children as young as 1-month old. We report a case of IFS in a newborn treated with larotrectinib. The patient experienced a rapid clinical and radiographic response demonstrating the potential to treat newborns with larotrectinib.

The impact of local control in the treatment of children with advanced infantile and adult-type fibrosarcoma: Experience of the cooperative weichteilsarkom studiengruppe (CWS)

BACKGROUND AND OBJECTIVES

This study aims at examining the potential survival benefits of primary versus secondary surgery of children diagnosed with advanced infantile (iFS) and adult-type fibrosarcoma (aFS).

METHODS

Treatment and outcome of 89 children with FS treated within prospective Cooperative Studiengruppe (CWS) trials (1981-2016) were analyzed retrospectively.

RESULTS

Localized disease (LD) was diagnosed in 87 patients: 64/66 patients with iFS (≤2 years) and 23 with aFS (>2 ≤ 18 years). Two patients (iFS) had metastatic disease. Resection was the mainstay of therapy of patients with LD resulting in microscopically complete (R0, IRS group I) (n = 29/87, 33%), microscopically incomplete (R1, IRS group II) (n = 17/87, 20%) and macroscopically incomplete (R2, IRS group III) (n = 41/87, 47%). Advanced LD (IRS group III) was present in 32/64 (50%) patients with iFS and in 9/23 (39%) with aFS. Chemotherapy was added predominantly in patients with advanced disease and an assessable objective response to CHT was seen in 71% iFS and 75% aFS. The 5-year event-free survival (EFS) of patients with iFS and aFS was 81% (±10, 95% CI) and 70% (±19, 95% CI) (p = 0.24); the 5-year overall survival (OS) was 98% (±3, 95% CI) and 82% (±16, 95% CI) (p = 0.02). Primary resection was no prognostic factor. Secondary R0/ R1 resection in patients with advanced disease improved 5-year EFS and OS in aFS (p = 0.002 and p = 0.000) but not in infants.

CONCLUSIONS

Secondary resection improves outcome in advanced aFS but not in infants. Mutilating surgery in infants should be avoided.

TYPE OF STUDY AND LEVEL OF EVIDENCE

Treatment study: patients were enrolled in five prospective studies and one registry, prognosis study: retrospective study.

LEVEL OF EVIDENCE

II/ III.

MINI-ABSTRACT

Fibrosarcoma is a very rare malignant tumor. Little is known about differences of local treatment of advanced infantile and adult-type. Data of 89 patients registered in five prospective trials and one registry of the Cooperative Weichteilsarkom Studiengruppe (CWS) (1981-2016) were analyzed.

Management of Refractory Pediatric Sarcoma: Current Challenges and Future Prospects

Paediatric sarcomas are a heterogeneous group of disorders constituting bone sarcoma and various soft tissue sarcomas. Almost one-third of these presents with metastasis at baseline and another one-third recur after initial curative treatment. There is a huge unmet need in this cohort in terms of curative options and/or prolongation of survival. In this review, we have discussed the current treatment options, challenges and future strategies of managing relapsed/refractory paediatric sarcomas. Upfront risk-adapted treatment with multidisciplinary management remains the main strategy to prevent future recurrence or relapse of the disease. In the case of limited local and/or systemic relapse or late relapse, initial multimodality management can be administered. In treatment-refractory cases or where cure is not feasible, the treatment options are limited to novel therapeutics, immunotherapeutic approach, targeted therapies, and metronomic therapies. A better understanding of disease biology, mechanism of treatment refractoriness, identifications of driver mutation, the discovery of novel targeted therapies, cellular vaccine and adapted therapies should be explored in relapsed/refractory cases. Close national and international collaboration for translation research is needed to fulfil the unmet need.

Cervical congenital infantile fibrosarcoma: a case report

Background

Congenital infantile fibrosarcoma is a rare mesenchymal tumor seen in children as well as adults. The congenital variety is rare and out of the reported cases only one case sited in the neck has been reported so far. Another such case is presented here who was successfully managed.

Case presentation

A 3-month-old Hindu baby boy presented with a congenital neck swelling. The apparent clinical diagnosis was lympho-venous malformation. With a remote possibility of malignancy, an excisional biopsy was done. Histopathology revealed congenital infantile fibrosarcoma.

Conclusion

A successful excision of cervical congenital infantile fibrosarcoma has not been reported. This diagnosis should be kept as a possibility in all congenital cervical swellings. These are commonly misdiagnosed as lympho-venous malformations and histopathology is confirmatory.

TRK Fusion Cancers in Children: A Clinical Review and Recommendations for Screening

Chromosomal translocations involving the NTRK1, NTRK2, and NTRK3 genes (TRK fusions), which encode the neurotrophin tyrosine kinase receptors TRKA, TRKB, and TRKC, can result in constitutive activation and aberrant expression of TRK kinase. Certain cancers almost universally harbor TRK fusions, including infantile fibrosarcoma, cellular congenital mesoblastic nephroma, secretory breast cancer, and mammary analog secretory carcinoma of the salivary gland. TRK fusions have also been identified at lower frequencies across a broad range of other pediatric cancers, including undifferentiated sarcomas, gliomas, papillary thyroid cancers, spitzoid neoplasms, inflammatory myofibroblastic tumors, and acute leukemias. Here we review the prevalence and diseases associated with TRK fusions and methods of detection of these fusions in light of the recent development of selective TRK inhibitors, such as larotrectinib, which demonstrated a 75% response rate across children and adults with TRK fusion cancers. We provide recommendations for screening pediatric tumors for the presence of TRK fusions, including the use of immunohistochemistry or fluorescence in situ hybridization for patients with tumors likely to harbor TRK fusions. Further, we recommend next-generation sequencing for tumors that have a relatively low prevalence of TRK fusions, both to identify patients who may benefit from TRK inhibition and to identify other targetable oncogenic drivers that exist in the same tumor types.

Recurrent EML4-NTRK3 fusions in infantile fibrosarcoma and congenital mesoblastic nephroma suggest a revised testing strategy

Infantile fibrosarcoma and congenital mesoblastic nephroma are tumors of infancy traditionally associated with the ETV6-NTRK3 gene fusion. However, a number of case reports have identified variant fusions in these tumors. In order to assess the frequency of variant NTRK3 fusions, and in particular whether the recently identified EML4-NTRK3 fusion is recurrent, 63 archival cases of infantile fibrosarcoma, congenital mesoblastic nephroma, mammary analog secretory carcinoma and secretory breast carcinoma (tumor types that are known to carry recurrent ETV6-NTRK3 fusions) were tested with NTRK3 break-apart FISH, EML4-NTRK3 dual fusion FISH, and targeted RNA sequencing. The EML4-NTRK3 fusion was identified in two cases of infantile fibrosarcoma (one of which was previously described), and in one case of congenital mesoblastic nephroma, demonstrating that the EML4-NTRK3 fusion is a recurrent genetic event in these related tumors. The growing spectrum of gene fusions associated with infantile fibrosarcoma and congenital mesoblastic nephroma along with the recent availability of targeted therapies directed toward inhibition of NTRK signaling argue for alternate testing strategies beyond ETV6 break-apart FISH. The use of either NTRK3 FISH or next-generation sequencing will expand the number of cases in which an oncogenic fusion is identified and facilitate optimal diagnosis and treatment for patients.

Infantile Fibrosarcoma: Retrospective Analysis of Eleven Patients

Aims and background

Infantile fibrosarcomas are soft tissue sarcomas that are diagnosed at or soon after birth. In the present study, we retrospectively evaluated clinical characteristics, treatment modalities and outcome of patients diagnosed with infantile fibrosarcoma at our institution.

Methods

A retrospective review was conducted to evaluate demographic characteristics, presenting features, type and timing of surgery, other treatment modalities and survival characteristics.

Results

Nine males and 2 females were diagnosed with infantile fibrosarcoma between 1970–2008. The initial surgical procedure was subtotal resection in 4 patients, gross-total resection in 3 and biopsy in 4. Neoadjuvant chemotherapy was given to 10 patients. Three patients died, one for the disease and 2 from complications of therapy. Eight patients are under follow-up with no evidence of disease for 1.3 to 13.5 years. None of the patients in the series underwent amputation.

Conclusions

Owing to the chemosensitive nature of the tumor and possibility of spontaneous regression, neoadjuvant chemotherapy should be considered to prevent extensive or mutilating surgery.

Neonatal congenital lung tumors - the importance of mid-second-trimester ultrasound as a diagnostic clue

BACKGROUND

The differential diagnosis for primary lung masses in neonates includes a variety of developmental abnormalities; it also consists of the much rarer congenital primary lung tumors: cystic pleuropulmonary blastoma (cystic PPB), fetal lung interstitial tumor (FLIT), congenital peribronchial myofibroblastic tumor (CPMT), and congenital fibrosarcoma. Radiologic differentiation between malformations and tumors is often very challenging.

OBJECTIVE

The objective was to establish distinctive features between developmental pulmonary abnormalities and primary lung tumors.

MATERIALS AND METHODS

We conducted a retrospective study of 135 congenital lung lesions at a university mother and child center over a period of 10 years (2005-2015). During this time, we noted four tumors (two cystic PPBs and two FLITs) and 131 malformations. We recorded the following parameters: timing of conspicuity in utero (mid-second trimester, third trimester, or not seen prenatally), presence of symptoms at birth, prenatal and perinatal radiologic findings, and either histological diagnoses by pathology or follow-up imaging in non-operated cases.

RESULTS

All lesions except the four tumors were detected during mid-second-trimester ultrasound. In none of the tumors was any pulmonary abnormality found on the mid-second-trimester sonogram, contrary to the developmental pulmonary abnormalities.

CONCLUSION

The timing of conspicuity in utero appears to be a key feature for the differentiation between malformations and tumors. Lesions that were not visible at the mid-second-trimester ultrasound should be considered as tumor. A cystic lung lesion in the context of a normal mid-second-trimester ultrasound is highly suggestive of a cystic PPB. Differentiating the types of solid congenital lung tumors based upon imaging features is not yet feasible.

Two cases of humoral hypercalcemia of malignancy complicating infantile fibrosarcoma

We report two infants with infantile fibrosarcoma (IFS) complicated by severe hypercalcemia. Assessment demonstrated suppressed parathyroid hormone and 1,25-dihydroxyvitamin D levels with elevated circulating levels of parathyroid hormone related protein, indicating the diagnosis of humoral hypercalcemia of malignancy (HHM). HHM is a paraneoplastic syndrome rarely associated with pediatric malignancies. Hypercalcemia manifested clinically with neurologic symptoms and soft tissue calcium deposition and required aggressive management with intravenous fluids, diuretics, and supplemental electrolytes. Following treatment with neoadjuvant chemotherapy, serum calcium levels precipitously declined requiring calcium repletion. These cases highlight the improvement of hypercalcemia secondary to HHM following chemotherapy.

Congenital intestinal fibrosarcoma with rapid recurrence requiring adjuvant chemotherapy

A total of 16 cases of congenital fibrosarcoma have been reported from 1975 to March 2015. Five of the 16 had abnormal fusion between erythroblast transformation specific translocation variant 6 and neurotrophin recptor gene neurotrophic tyrosine kinase, receptor, type 3 (ETV6-NTRK3); in another five out of 16 this was absent, and six were not tested. All were managed by surgical resection but none involved metastasis. Herein we report the case of a newborn baby girl with congenital fibrosarcoma negative for ETV6-NTRK3 gene fusion, who presented with ileal perforation and positive resection margin. She had rapid recurrence with lymph node metastasis treated with postoperative chemotherapy. There was no further recurrence at >3 years of follow up.

Mimickers of Infantile Hemangiomas

Infantile hemangiomas (IHs) are the most common tumors of infancy and usually follow a typical course of growth and involution. We report four soft tissue tumors that were referred to the pediatric dermatology clinic as IHs and the process by which they were diagnosed and treated. Clinicians should be aware of presentations of these uncommon, but serious soft tissue tumors. Many of these mimickers have a vastly different clinical prognosis, and early intervention to limit sequelae is crucial. Biopsy of atypical lesions should be considered early in the diagnostic process since they have varied prognosis and treatment strategies.

Infantile fibrosarcoma treated with postoperative vincristine and dactinomycin

Infantile fibrosarcoma is a non-rhabdomyosarcoma soft-tissue sarcoma that occurs in infancy and which has a relatively good prognosis. A vincristine and dactinomycin (VA) regimen has been shown to be effective, although the duration of chemotherapy has not been well defined. We describe the case of a 4-month-old boy with a mass at the left dorsum of the foot who was diagnosed with infantile fibrosarcoma after resection of the tumor, the margin of which was macroscopically positive. VA treatment was carried out with careful monitoring of response and adverse effects. Pancytopenia was seen during the second cycle, and therapy was reduced thereafter. The treatment was continued for 38 weeks (12 cycles). There was no functional impairment, and no evidence of recurrence at 18 months after therapy.

Non-rhabdomyosarcoma

Pediatric non-rhabdomyosarcoma soft tissue sarcomas (NRSTS) are a heterogeneous group encompassing more than 50 different histological diagnoses arising from primitive mesenchymal tissue. Together, they comprise about half the soft tissue sarcomas diagnosed in children and young adults. Despite each histologies relative rarity, their management schema is similar among the different NRSTS histologies. Surgical management is an important component of the multimodal treatment strategy of all these tumors. Resection with negative margins, while maintaining function, plays an important role as a primary treatment of these patients as well as diminishing the risks of local and distant recurrence.

Infantile Fibrosarcoma With NTRK3-ETV6 Fusion Successfully Treated With the Tropomyosin-Related Kinase Inhibitor LOXO-101

Infantile fibrosarcoma (IFS) is a rare pediatric cancer typically presenting in the first 2 years of life. Surgical resection is usually curative and chemotherapy is active against gross residual disease. However, when recurrences occur, therapeutic options are limited. We report a case of refractory IFS with constitutive activation of the tropomyosin-related kinase (TRK) signaling pathway from an ETS variant gene 6-neurotrophin 3 receptor gene (ETV6-NTRK3) gene fusion. The patient enrolled in a pediatric Phase 1 trial of LOXO-101, an experimental, highly selective inhibitor of TRK. The patient experienced a rapid, radiographic response, demonstrating the potential for LOXO-101 to provide benefit for IFS harboring NTRK gene fusions.

Primitive Spindle Cell Neoplasm of Ileum with Extensive Heterotopic Cartilage, Presenting as Acute Abdomen in a 6-Day-Old Neonate

Neonatal intestinal masses with spindle cell morphology have broad differential diagnoses and require a multidisciplinary approach to make the final diagnosis. Spindle cell masses with heterotopic cartilage in the gastrointestinal tract are very rare, and, to our knowledge, have not previously been reported in the neonate. Here we present a case of intestinal primitive spindle cell neoplasm with extensive heterotopic cartilage that manifested initially as acute abdomen in a 6-day-old term infant. Plain radiography demonstrated pneumoperitoneum, prompting diagnostic laparotomy that identified a perforated mass involving the midileum. Histologic and immunohistochemical examination demonstrated an infiltrative spindle cell tumor most compatible with infantile fibrosarcoma (IFS) by a process of exclusion, with nodules of mature heterotopic cartilage. Additional staging studies did not reveal any evidence of residual or metastatic disease. Recognition of this rare variant of IFS will aid in differentiation from other neonatal intestinal mesenchymal tumors.

Primary Pulmonary Fibrosarcoma With Bone Metastasis: a Successful Treatment With Post-Operation Adjuvant Chemotherapy

Introduction:

Pulmonary fibrosarcoma has been an extremely rare tumor in children. Wide surgical resection of infantile fibrosarcoma would be the treatment of choice.

Case Presentation:

Post-operative chemotherapy has shown the benefit in the cases of residual disease after initial surgery and metastatic disease in the literature. We have presented the case of a 70-days old male child with primary infantile fibrosarcoma of the left lung and distant metastasis of skull.

Conclusions:

The aim of this publication was to highlight the role of adjuvant chemotherapy to improve outcome of infantile fibrosarcoma with residual tumor and / or metastatic disease.

New concepts for the treatment of pediatric nonrhabdomyosarcoma soft tissue sarcomas

Nonrhabdomyosarcoma soft tissue sarcomas form a group of rare tumors with a different biology and clinical behavior. The recently established European Pediatric Soft Tissue Sarcoma Study Group is organizing a new study devoted specifically to these tumors that were formerly treated according to the principles derived from experience with rhabdomyosarcoma, which is a clearly distinct entity. The new study includes two prospective trials, one for synovial sarcoma and the other for adult-type nonrhabdomyosarcoma soft tissue sarcomas. While surgery remains the mainstay of treatment, the role of adjuvant therapy is not yet clear and our understanding of the biology and natural history of nonrhabdomyosarcoma soft tissue sarcomas is still incomplete. This review presents the latest data on nonrhabdomyosarcoma soft tissue sarcoma treatment and outcome, and the rationale behind a risk-adapted treatment program that investigates the role of full-dose ifosfamide-doxorubicin chemotherapy in improving the response rate of patients with unresectable disease, the chances of avoiding adjuvant chemotherapy in low-risk synovial sarcomas, and the possible role of chemotherapy in high-risk adult-type soft tissue sarcomas.

Treatment options for children with nonrhabdomyosarcoma soft tissue sarcoma

Nonrhabdomyosarcoma soft tissue sarcomas account for approximately 40% of all soft tissue sarcomas in children. Although these tumors are typically grouped together, individual tumor types with different biological characteristics have been found that may impact on the optimal therapy for each type of sarcoma in the future. Most of the current information regarding this tumor comes from the adult literature. Wide local excision appears to provide the best chance of cure. Future studies are needed to determine which adjuvant therapies are most useful in improving local control and overall survival in the different subsets of patients.

Congenital infantile fibrosarcoma of the lip

Infantile congenital fibrosarcomas are rare neoplasms that usually present on the extremities, and although they are locally invasive, they rarely metastasize. They are commonly misdiagnosed as hemangiomas or other vascular tumors, so further evaluation by pathology is required for proper diagnosis. We describe a newborn with a neoplastic growth of the lower lip that was thought to be an infantile hemangioma that did not respond to therapy. When the child was 2 months old, an incisional biopsy demonstrated a fibrosarcoma. This case highlights congenital infantile fibrosarcoma as a mimic of infantile hemangioma. To our knowledge this is first case report of congenital infantile fibrosarcoma involving the lip.

Infantile fibrosarcoma misdiagnosed as vascular tumors

Clinical as well as radiologic diagnosis of infantile fibrosarcoma (IFS) is often a challenging problem due to similarities with tumors of vascular origin. Consequently, in the majority of cases, histological and immunohistochemical studies are considered gold standards for the final diagnosis. The two case reports and the review of literature discussed should increase the important features in the history and the presentation that increase the index of suspicion for IFS, as well as it highlights the important characteristics of imaging and laboratory studies that confirm its diagnosis.

Margin status and multimodal therapy in infantile fibrosarcoma

PURPOSE

The rarity of infantile fibrosarcoma (IF) has precluded comprehensive treatment evaluation. The purpose of this study was to better define the extent of surgical resection required and the role of chemotherapy.

METHODS

Patients (0-2 years) with IF were evaluated from the National Cancer Data Base (1985-2007). Survival was estimated using the Kaplan-Meier method stratifying patients by margin status and treatment with or without chemotherapy.

RESULTS

Of the 224 patients, 171 (76.3 %) were <1 year of age. Of the 64 (28.6 %) with positive margins, 36 (56.3 %) had microscopic disease, 12 (18.8 %) had macroscopic disease, and 16 (25 %) had unknown margin status; none were found to have metastases. Most were managed with surgical resection (171, 76.4 %). The proportion treated with both surgery and chemotherapy increased over time (18-40 %, p = 0.025). Disease-free survival was 90.6 %. No significant survival difference was noted in this retrospective, non-randomized cohort based on margin status, nodal involvement, tumor size, or treatment modality.

CONCLUSIONS

The use of multimodal therapy has increased over time. There was a small increase in survival associated with negative margins and the use of multimodal therapy, however, neither result reached significance. Future studies investigating tumor biology and chemosensitivity will likely determine the optimal management of IF.

Clinical management of infantile fibrosarcoma: a retrospective single-institution review

BACKGROUND

Infantile fibrosarcoma (IFS) is an uncommon soft-tissue sarcoma. Here we review our experience treating this tumor.

PATIENTS AND METHODS

We retrospectively reviewed records of patients with IFS treated at St. Jude Children's Research Hospital between 1980 and 2009.

RESULTS

We identified 15 patients, 8 girls and 7 boys; 13 white and 2 black. Median age at diagnosis was 3 months. Primary sites included the leg (n = 3), chest wall (n = 2), foot (n = 2), and one each in the tongue, occipital region, axilla, parascapular region, arm, forearm, retroperitoneum, and thigh. All patients underwent resection; 11 upfront surgery, and 4 delayed. Complications included loss of the posterior tibial nerve and artery, axillary vein, biceps, pectoralis major, gallbladder, and transverse/sigmoid sinus. Eight received chemotherapy and three radiotherapy. Seven experienced local recurrence and three lung metastasis. Median follow-up was 65 months. At the time of the review, 12 patients were alive and 3 had died. All deaths were in patients older than 1 year at diagnosis with an axial primary site.

CONCLUSIONS

Non-mutilating surgery should be the primary treatment for IFS. Neoadjuvant chemotherapy is indicated when upfront resection is unfeasible. Patients with positive surgical margins should receive adjuvant chemotherapy. Radiotherapy is indicated for axial primary sites where complete resection is impossible.

Cardiac metastasis and hypertrophic osteoarthropathy in recurrent infantile fibrosarcoma

Cardiac metastasis and hypertrophic osteoarthropathy are both quite rare. We describe a patient presenting with hypertrophic osteoarthropathy as the first symptom of recurrent infantile fibrosarcoma (IF). During surgical resection of lung metastasis, the patient suffered sudden cardiac arrest. Autopsy demonstrated a metastatic lesion in the intraventricular septum of the heart, which is previously undescribed in the literature. This case demonstrates that IF can be aggressive despite its more typical benign course.

Recurrent congenital fibrosarcoma with heart metastases

Congenital fibrosarcomas are malignant tumors that arise in soft tissues. In infants this unique tumor does not commonly metastasize, even though there may be local recurrences. We report here a boy who had congenital fibrosarcoma in his right foot, which was completely excised at the age of 3 days. Four months later, a solitary encapsulated metastasis emerged in thoracic chest wall, which was operated. During adjuvant chemotherapy he developed histologically confirmed fibrosarcoma metastases in the heart. After extended treatment with cyclophosphamide/topotecan and gemcitabine/docetaxel, the heart tumors disappeared and he has been in complete remission for 3 years.

[Fibrosarcoma in children and adolescents: different entities for the same name]

Fibrosarcomas (FS) are rare malignant tumors in pediatrics, classified in the heterogeneous non-rhabdomyosarcomas group of malignant mesenchymal tumors. Infantile FS are found typically in children less than 2 years of age, and include congenital FS usually occurring in infants in the first 3 months of life. Histological diagnosis can be difficult; and confirmed with detection by molecular biology of the ETV6-NTRK3 fusion protein. FS is most often a localized disease at diagnosis, with involvement of an extremity. The management of these patients must be multidisciplinary, to define the different phases of treatment and avoid mutilating surgery. Cellular or atypical mesoblastic nephroma (MN) is a subtype of malignant pediatric renal tumors, most often present in children of less than 3 months. Histopathological characteristics of the cellular MN are very close to the congenital FS due to a fusion transcript common to both diseases. Treatment schedule is defined by initial local stage of the disease. FS called "adult-type" found exceptionally in childhood occur most often after 10 years old. Adult FS differ from infantile FS in their clinical presentation because of a strong local aggressiveness and problematic appearance of metastasis in 50% of cases, sometimes late. These three diseases present therefore histological similarities. Both have a common name but different clinical presentation and outcome: infantile FS and adult FS. Two have different names and initial location but similar histology, chromosomal rearrangement, sensitivity to chemotherapy and outcome: the congenital FS and cellular mesoblatic nephroma. Authors present a review of the literature of these entities.

Pediatric soft tissue sarcomas

After a brief discussion of the rarity of soft tissue sarcomas in children and of the limited ability of magnetic resonance imaging to provide a tissue diagnosis, this article discusses the incidence, presentation, treatment, prognosis, and imaging characteristics of the more common and unusual pediatric soft tissue sarcomas. It begins with extensive discussion of rhabdomyosarcoma, synovial sarcoma, and congenital/infantile fibrosarcoma. It then presents a more abbreviated discussion of uncommon tumors such as alveolar soft part sarcoma, epithelioid sarcoma, extraosseous Ewing's sarcoma, granulocytic sarcoma, hemangiopericytoma, liposarcoma, malignant fibrous histiocytoma, malignant peripheral nerve sheath tumor, and undifferentiated sarcoma.

Congenital-infantile fibrosarcoma masquerading as sacrococcygeal teratoma

Infantile fibrosarcoma is rare and represents less than 1% of all childhood cancers. Commonly, it arises in the limbs followed by the trunk and head and neck. We report a rare case of infantile fibrosarcoma masquerading as sacrococcygeal teratoma in a newborn. The literature on the subject is also reviewed.

Challenging issues in pediatric oncology

Improvements in protocol-driven clinical trials and supportive care for children and adolescents with cancer have reduced mortality rates by more than 50% over the past three decades. Overall, the 5-year survival rate for patients with pediatric cancer has increased to approximately 80%. Recognition of the biological heterogeneity within specific subtypes of cancer, the discovery of genetic lesions that drive malignant transformation and cancer progression, and improved understanding of the basis of drug resistance will undoubtedly catalyze further advances in risk-directed treatments and the development of targeted therapies, boosting the cure rates further. Emerging new treatments include novel formulations of existing chemotherapeutic agents, monoclonal antibodies against cancer-associated antigens, and molecular therapies that target genetic lesions and their associated signaling pathways. Recent findings that link pharmacogenomic variations with drug exposure, adverse effects, and efficacy should accelerate efforts to develop personalized therapy for individual patients. Finally, palliative care should be included as an essential part of cancer management to prevent and relieve the suffering and to improve the quality of life of patients and their families.

Congenital infantile fibrosarcoma of the forearm

Congenital infantile fibrosarcoma is a rare soft tissue neoplasm in the infant of which only a few cases are reported as congenital. This tumor has a rapid growth and extensive local invasion, but metastasis rarely occurs. Distal extremities involvement is more common and metastasis are rare. We report a case of a congenital infantile fibrosarcoma of the forearm, which was initially confused with a hemangioma, treated successfully by surgical resection.

[Recurrent and metastatic infantile fibrosarcoma: a case report]

Infantile fibrosarcoma is a rare malignant tumor that usually occurs during the 1st year of life. It accounts for approximately 5-10% of all sarcomas in infants younger than 1 year of age. It usually has indolent progression and metastatic spread is rare. We report the case of a patient who had infantile fibrosarcoma of the trunk. At birth, the baby presented a soft tissue mass of the scapulothoracic region. Histopathological examination after complete surgical resection at first suggested an angioma. Reanalysis of the histology after a metastatic relapse resulted in the diagnosis of infantile fibrosarcoma, which was confirmed by the presence of the specific translocation seen in infantile fibrosarcoma (ETV6/NTRK3). This patient's progression was uncommon because he developed 3 metastatic relapses. The treatment consisted of surgery, chemotherapy, and radiation therapy. The patient is alive with persistent complete remission. We discuss the diagnostic and therapeutic issues of infantile fibrosarcoma. There is a risk of erroneous diagnosis in newborn infants between benign angiomatous tumor and infantile fibrosarcoma. The fusion transcript ETV6-NTRK3 resulting from the specific chromosomal translocation t(12;15)(p13;q25) is now a useful diagnostic tool for infantile fibrosarcoma. Surgery with wide resection is the mainstay of treatment. However, infantile fibrosarcoma is a chemosensitive tumor. If initial surgery cannot be done without mutilation or is impossible, preoperative chemotherapy should be given. The role of radiation therapy is still debated.

Infantile myofibroma or lymphatic malformation: differential diagnosis of neonatal cystic cervicofacial lesions

A 5-day-old male neonate was referred to our vascular anomalies center with a large cystic submandibular mass. History and physical examination and ultrasonographic results indicated the diagnosis to be macrocystic lymphatic malformation. Consequently, the child was treated with sclerotherapy and subtotal excision. The histopathological examination result showed that the lesion was infantile myofibroma. This diagnostic error was attributed to atypical features of infantile myofibroma in this child: unusually large cysts, rapid enlargement, and coagulopathy. This report expands the clinical spectrum of infantile myofibromatosis and suggests its consideration in the differential diagnosis of neonatal cystic cervicofacial lesions.

Myofibroblastic Tumors in Children

Pediatric myofibroblastic tumors comprise a clinically and pathologically heterogeneous group of neoplasms, including benign tumors, those of intermediate biologic potential, and frankly malignant examples (Box 1). Proper classification is critical for appropriate prognostication, clinical management, and, in some cases, identification of familial syndromes. Unlike for many other soft tissue tumors, immunohistochemistry plays a limited role in the diagnosis of pediatric myofibroblastic tumors, with notable exceptions. Understanding the molecular genetics underlying the pathogenesis of several tumor types in this group has led to improved tools for diagnosis. This article discusses the clinical and pathologic features of myofibroblastic tumors in children, with special emphasis on differential diagnosis.