Infantile fibrosarcoma

Activating neurotrophic receptor kinase (NTRK) fusions define certain pediatric mesenchymal tumors, including infantile fibrosarcoma and cellular mesoblastic nephroma. Traditionally, molecular confirmation of these fusions has included either fluorescent in situ hybridization for ETV6 rearrangements or reverse-transcriptase polymerase chain reaction for the classic ETV6-NTRK3 fusion. However, these methods overlook variant NTRK rearrangements, which are increasingly appreciated as recurrent events in a subset of pediatric mesenchymal tumors...

A two-year-old boy presented with a large, non-healing ulceration on his left buttock, which was originally noted as a brown patch present at birth. Punch skin biopsy was performed and histopathology revealed an atypical, pleomorphic, spindled proliferation in whorled fascicles replacing the dermis and trapping fat in the subcutis, consistent with a diagnosis of congenital/infantile fibrosarcoma. No evidence of metastatic spread was seen on imaging. The tumor was initially deemed unresectable owing to extent of local invasion...

Malignant soft tissue tumours are rare in infants. Specific radiologic features help differentiate benign from malignant musculoskeletal entities. We report a case of malignant soft tissue tumour with initial radiologic evaluation suggesting a benign entity, thus delaying diagnosis. The case was treated as a case of cystic hygroma, suggested by ultrasound and MRI with good initial response to bleomycin injection. Later, symptoms recurred with poor response to repeat therapy which led to review the diagnosis...

BACKGROUND: Gene fusions involving NTRK1, NTRK2, or NTRK3 (TRK fusions) are found in a broad range of paediatric and adult malignancies. Larotrectinib, a highly selective small-molecule inhibitor of the TRK kinases, had shown activity in preclinical models and in adults with tumours harbouring TRK fusions. This study aimed to assess the safety of larotrectinib in paediatric patients. METHODS: This multicentre, open-label, phase 1/2 study was done at eight sites in the USA and enrolled infants, children, and adolescents aged 1 month to 21 years with locally advanced or metastatic solid tumours or CNS tumours that had relapsed, progressed, or were non-responsive to available therapies regardless of TRK fusion status; had a Karnofsky (≥16 years of age) or Lansky (<16 years of age) performance status score of 50 or more, adequate organ function, and full recovery from the acute toxic effects of all previous anticancer therapy...

This corrects the article DOI: 10.1038/modpathol.2017.12.

Chromosomal rearrangements that facilitate tumor formation and progression through activation of oncogenic tyrosine kinases are frequently observed in cancer. The ETV6-NTRK3 (EN) fusion has been implicated in various cancers, including infantile fibrosarcoma, secretory breast carcinoma, and acute myeloblastic leukemia, and has exhibited in vivo and in vitro transforming ability. In the present study, we analyzed transcriptome alterations using DNA microarray and RNA-Seq in EN-transduced NIH3T3 fibroblasts to identify the mechanisms that are involved in EN-mediated tumorigenesis...

An infant boy underwent hip disarticulation for infantile fibrosarcoma immediately after birth. His rehabilitation began when he was 4 months old and involved training with his left (residual) leg. He could stand with support at 12 months. His initial prosthesis fitting was performed at the age of 13 months. He could stand and walk with support at 15 months of age and could walk with no additional support and go up and down stairs at 2 years. A single-axis prosthetic knee joint was introduced at the age of 2 years 3 months...

Infantile fibrosarcoma usually presents as a rapidly growing mass on the extremities or trunk. We describe spontaneous regression in a 5-month-old female infant with biopsy proven, molecularly confirmed, right leg infantile fibrosarcoma currently at 26 months of age with no signs of local recurrence. Previously reported cases of spontaneous regression are reviewed, suggesting a benign clinical course in some cases. Although evidence for spontaneous regression is anecdotal in this rare tumor type, physicians should weigh the risks and benefits of surgery and chemotherapy against watchful waiting...

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...

BACKGROUND: Congenital infantile fibrosarcoma (CIF) is rare and represents less than 1% of all childhood cancers. It is a tumor that originates in the connective fibrous tissue found at the ends of long bones and then spreads to other surrounding soft tissues. These lesions are typically large, grow rapidly, and can often be mistaken for teratomas. Diagnosis is confirmed by pathology, where cellular proliferation of fibroblasts occurs. Imaging is an important part of the diagnosis, which includes the use of magnetic resonance imaging and/or computed tomography scan...

Neonatal intussusception of the intestinal tract is rare. However, most neonatal intussusceptions have an organic lead point. For the lead point to be a neoplasm is extremely rare. We report a case that presented with neonatal intussusception with a congenital infantile fibrosarcoma as the lead point. The detection of ETV6-NTRK3 gene fusion was useful, although the definitive diagnosis was achieved by a comprehensive evaluation including this gene analysis, standard histology and immunohistochemistry. Neonatal intussusception should be suspected to be caused by a neoplasm...

OBJECTIVE: Vascular anomalies in the neonatal period are a diagnostic challenge for the lack of evident signs, symptoms and follow-up, and the convenience of restricting aggressive diagnostic tests. The aim of this work is to review the characteristics of neonatal cases presented to our Vascular Anomalies Unit in the last 5 years. MATERIALS AND METHODS: All cases of suspected vascular anomaly presented to our unit before 1 month of age between 2010 and 2015 were reviewed, diagnostic tests and treatments carried out with chronology were analyzed...

BACKGROUND: Infantile fibrosarcoma (IFS) is a rare pediatric malignancy with relatively good prognosis, but the risk of progression or recurrence after therapy exists. To understand the immune microenvironment of IFS and determine if immunotherapy is a potential treatment, we analyzed T-cell responses in IFS tumors. PROCEDURE: IFS tumors were analyzed by immunohistochemistry and multicolor flow cytometry to characterize immune cell infiltration and function. Tumor infiltrating lymphocytes (TILs) were expanded in vitro and evaluated for recognition of autologous tumor cells...

Infantile fibrosarcomas (IFS) represent a distinct group of soft tissue tumors occurring in patients under 2 years of age and most commonly involving the extremities. Most IFS show recurrent ETV6-NTRK3 gene fusions, sensitivity to chemotherapy, and an overall favorable clinical outcome. However, outside these well-defined pathologic features, no studies have investigated IFS lacking ETV6-NTRK3 fusions, or tumors with the morphology resembling IFS in older children. This study was triggered by the identification of a novel SEPT7-BRAF fusion in an unclassified retroperitoneal spindle cell sarcoma in a 16-year-old female by targeted RNA sequencing...

PURPOSE: Fifty years ago, Bolande described Congenital Mesoblastic Nephroma (CMN) as a benign lesion. Unexpected aggressive clinical behaviors prompted a sub-classification based on histology. Recent molecular genetic evidence has identified the aggressive cellular variant to be the renal manifestation of congenital infantile fibrosarcoma. We submit a reappraisal and analysis of the available literature on recurrent and metastatic CMN. METHODS: An electronic search of PubMed, MEDLINE, EMBASE, and Scopus yielded 38 children with local recurrence and/or metastases...

Congenital infantile fibrosarcoma (CIF) is a rare malignant mesenchymal tumor and only 14 cases have been reported with gastrointestinal manifestation. We report about a female newborn delivered per emergency cesarean section at 34 weeks of gestation. Postnatally, she rapidly developed an acute abdomen and sonographic evidence of intestinal perforation requiring laparotomy on the first day of life. A perforated 2 × 3 cm sized spherical tumorous structure of the jejunum was identified. Due to unknown histopathology at this point and unclear resectional margins, she received a temporary ileostomy, which was closed two months later...

Pediatric fibroblastic/myofibroblastic lesions are a relatively common group of tumors with varying morphologies, for which the molecular mechanisms are becoming increasingly well characterized. Congenital infantile fibrosarcoma (CIFS), perhaps the most well studied of these lesions is characterized by a recurrent ETV6-NTRK3 gene fusion. However, a notable subset of locally aggressive congenital/infantile soft tissue lesions with similar morphologic features to CIFS, have not to-date, shown evidence of any canonical molecular aberration...

Congenital infantile fibrosarcoma (CIFS) is a soft tissue sarcoma of infants mainly involving lower extremities and usually developing during the first year of life. At another end of the spectrum of pediatric fibroblastic lesions, lipofibromatosis is a rare benign infiltrative soft tissue tumor that affects children. The authors report in this study a particular presentation with a CIFS surrounded by lipofibromatosis-like areas. The presence of a surrounding benign tumor confused and delayed CIFS diagnosis...

An increasing number of congenital and infantile sarcomas displaying a primitive, monomorphic spindle cell phenotype have been characterized to harbor recurrent gene fusions, including infantile fibrosarcoma and congenital spindle cell rhabdomyosarcoma. Here, we report an unusual spindle cell sarcoma presenting as a large and infiltrative pelvic soft tissue mass in a 4-month-old girl, which revealed a novel TFG-MET gene fusion by whole transcriptome RNA sequencing. The tumor resembled the morphology of an infantile fibrosarcoma with both fascicular and patternless growth, however, it expressed strong S100 protein immunoreactivity, while lacking SOX10 staining and retaining H3K27me3 expression...

We describe a patient who presented with a congenital soft tissue lesion initially diagnosed as infantile fibromatosis at 15 days of age. Unusually, the mass demonstrated malignant progression leading to death at 20 months of age. Biological progression to malignancy is not known to occur in fibromatosis, and fibrosarcoma is not known to progress from a benign lesion. Whole-exome sequencing of the tumor identified a driver mutation in histone H3.1 at lysine (K)36. Our findings support the link between oncohistones and infantile soft tissue tumors and provide additional evidence for the oncogenic effects of p...