Fibromatosis and fibrosarcoma in infancy and childhood

Progressive insights into fibrosarcoma diagnosis and treatment: leveraging fusion genes for advancements

Fibrosarcoma, originating from fibroblast cells, represents a malignant neoplasm that can manifest across all genders and age groups. Fusion genes are notably prevalent within the landscape of human cancers, particularly within the subtypes of fibrosarcoma, where they exert substantial driving forces in tumorigenesis. Many fusion genes underlie the pathogenic mechanisms triggering the onset of this disease. Moreover, a close association emerges between the spectrum of fusion gene types and the phenotypic expression of fibrosarcoma, endowing fusion genes not only as promising diagnostic indicators for fibrosarcoma but also as pivotal foundations for its subcategorization. Concurrently, an increasing number of chimeric proteins encoded by fusion genes have been substantiated as specific targets for treating fibrosarcoma, consequently significantly enhancing patient prognoses. This review comprehensively delineates the mechanisms behind fusion gene formation in fibrosarcoma, the lineage of fusion genes, methodologies employed in detecting fusion genes within fibrosarcoma, and the prospects of targeted therapeutic interventions driven by fusion genes within the fibrosarcoma domain.

INI1 negative sarcoma diagnosed as malignant rhabdoid tumor presenting as hydrops fetalis metastatic to the placenta: a case report and review of the literature on congenital sarcomas

Rhabdoid tumor is a highly aggressive sarcoma found in young children that occurs in the kidney, central nervous system and soft tissue sites. Rarely, it presents in the fetus or neonate and is associated with a dismal prognosis. We report a case of a 28-week gestation fetus presenting with hydrops fetalis who died soon after delivery, found at autopsy to have a rhabdoid tumor of the thoracic cavity with placental metastases and provide a review of the literature of congenital sarcomas.

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.

Infantile fibromatosis of the pterygomandibular space

Infantile fibromatosis (IF) is a benign, nonmetastasizing but locally aggressive tumor. Pterygomandibular space is deep and obscure, and IF in this space is seldom reported. We describe a typical case of IF in the pterygomandibular space that occurred in a 3-year-old girl. Intraoral incisional biopsy revealed the diagnosis of IF, and surgical resection of the tumor was performed. We intend to heighten the awareness of this tumor and emphasize the pathologic features and identifications of IF and discuss the diagnosis and treatment of this disease. For the high recurrence risk, follow-up with clinical examination and magnetic resonance imaging in pediatric patients is recommended.

Pediatric fibroblastic and myofibroblastic lesions

Fibrous lesions of infancy and childhood are a heterogeneous group of entities composed predominantly of fibroblasts and myofibroblasts, ranging from reactive lesions to neoplasms with a range of malignant potential. Although rare, their correct recognition by histopathology is important clinically as they exhibit a wide range of behaviors and may be associated with distinct underlying syndromes. Contributions from molecular diagnostics have enabled more accurate diagnosis, and have changed our concepts of some tumor types. In this review, we discuss the clinicopathologic spectrum of fibroblastic and myofibroblastic lesions of childhood and adolescence.

Congenital infantile fibromatosis of the cheek: report of a rare case and differential diagnosis

Infantile fibromatosis is a benign tumour that consists of dense masses of fibroblasts and myofibroblasts with marked collagen production. Although it is a nonmetastasising tumour, it has significant potential for local invasion and recurrence and may be fatal because of its size and location. The authors report an unusual case of infantile fibromatosis of the cheek in an 8-month-old boy, present since birth. The patient underwent surgical treatment with tumour-free margins and the 6-month follow-up revealed no signs of recurrence. Infantile fibromatosis of the cheek is a very rare condition at this location, especially congenital cases. It should be considered in the differential diagnosis of congenital lesions in childhood.

Diphenylhydantoin plays a role in gene expression related to cytoskeleton and protein adhesion in human normal palate fibroblasts

AIMS

Morphogenetic processes during palate development are related to extracellular matrix composition. The cell-extracellular matrix relation plays a role in cell activity and in gene expression. We studied the effect of diphenylhydantoin, a teratogen known to induce cleft palate in human newborns, on extracellular matrix production. We investigated whether diphenylhydantoin treatment caused any differences in glycosaminoglycans, collagen synthesis and gene expression in human normal palate fibroblasts.

METHODS

Human palate fibroblasts were maintained for 24 hours in serum-free 199 medium containing 5 microg/mL (3)H-glucosamine or (3)H proline hydrochloride. Collagen and glycosaminoglycan classes were then measured using biochemical methods, gene expression with microarray analysis and cytoskeleton components with immunofluorescent antibodies and computer analysis.

RESULTS

In normal fibroblasts diphenylhydantoin reduced collagen and glycosaminoglycan synthesis with a marked effect on sulphated glycosaminoglycans. There were also substantial decreases in tubulin, vimentin and alpha-actin staining and an increase of vinculin compared to controls. Diphenylhydantoin acted on several genes related to the synthesis of cytoskeleton and adhesion membrane proteins. It inhibited caderin, caveolin, RTK and alpha-actin, and increased nectin, cytoplasmatic FRG vinculin, ITGA, ITGB extracellular matrix ligand and EDG2 gene expression. DNA binding gene expression, which plays a role in cell growth and senescence, was activated.

CONCLUSIONS

Since cell activity is dependent on the cell morphology and extracellular matrix composition, these findings indicate that in human normal palate fibroblasts diphenylhydantoin can modify cytoskeletal components and extracellular matrix-cell adhesion, with consequent effects on gene expression. These changes might be related to anomalous palate development.

Primary colonic congenital infantile fibrosarcoma presenting as meconium peritonitis

Congenital infantile fibrosarcoma is a rare soft tissue malignancy that occurs in both axial and extremity locations. We report a case of this tumor arising from the left colon in a newborn presenting with an intrauterine perforation and meconium peritonitis.

Toremifene decreases type I, type II and increases type III receptors in desmoid and fibroma and inhibits TGFbeta1 binding in desmoid fibroblasts

Tissue infiltration is different in desmoid and fibroma tumours. Both produce high levels of transforming growth factor beta1 (TGFbeta1), which is related to extracellular matrix (ECM) accumulation which in turn regulates cell function and cell migration. Interactions between collagen, proteoglycans and cell surface fibronectin are involved in the assembly and functions of the ECM. As toremifene inhibits collagen and TGFbeta1 synthesis, we tested it in normal, desmoid and fibroma fibroblasts. We will report the changes in glycosaminoglycan (GAG) and collagen synthesis, TGFbeta1 activity, fibronectin mRNA expression and TGFbeta1 receptors after toremifene treatment in normal, fibroma and desmoid fibroblasts. We evaluated GAG and collagen synthesis with 3H-glucosamine and 3H-proline incorporation, TGFbeta1 activity with the ELISA method, TGFbeta1 receptor affinity with 125I-TGFbeta1 binding and total RNA with Northern blot analysis. GAG and collagen synthesis, TGFbeta1 activity and fibronectin levels were higher in fibroma and desmoid than normal fibroblasts. The increase was greater in desmoid than fibroma tumour cells. Toremifene treatment reduced GAG and collagen synthesis, TGFbeta1 activity and fibronectin levels in all cell cultures. The percentage reduction in GAG was similar in all cultures; the reduction in collagen synthesis and TGFbeta1 activity was the highest in desmoid fibroblasts. TGFbeta1 receptors were higher in fibroma and desmoid cells than controls. Toremifene reduced TGFbeta1 receptors only in desmoid fibroblasts, with no effect on the changes in type I, II, and III receptors. Our data show that toremifene modifies the ECM components that regulate cytokine activity and cell migration. The reduction in receptor number only in desmoid cells suggests that toremifene may reduce TGFbeta1's affinity for its receptors. Synthesis of a substance regulating protein kinase activity, which is directly involved in the link between TGFbeta1 and its receptors, cannot be excluded.

Desmoid and fibroma tumors differently respond to TGFβ1 stimulus and ECM macromolecule accumulation

Desmoid and fibroma tumours are characterized by cell proliferation, glycosaminoglycan and collagen fibre accumulation, high levels of transforming growth factor beta(1) (TGFbeta(1)) and different patterns of tissue infiltration. TGFbeta(1) is related to extracellular matrix (ECM) composition which, in turn, regulates cell functions and cell migration. In this study we report changes in cell proliferation, glycosaminoglycan (GAG) and collagen synthesis, TGFbeta(1) mRNA expression and fibronectin levels in normal, desmoid and fibroma fibroblast cultures before and after TGFbeta(1) stimulation. Our data showed cell proliferation, GAG and collagen synthesis, transforming growth factor beta(1) mRNA expression and fibronectin levels were significantly higher in desmoid than in fibroma cultures. TGFbeta(1) treatment had no effect on cell proliferation, but increased TGFbeta(1) mRNA expression, GAG, fibronectin and collagen synthesis in desmoid and fibroma fibroblasts. Its effects were more marked in desmoid cells. Fibronectin favours cell migration, while changes in GAG composition alter cell behaviour and ECM organization. In conclusion our data suggest that the different patterns of infiltration in desmoid and fibroma tumours are due to changes in ECM components and cell-ECM interactions which can be ascribed to altered TGFbeta(1) mRNA expression and TGFbeta(1) activity.

[Malignant solid tumors in neonates: a study of 71 cases]

Malignant neonatal tumors are rare and comprise 2% of childhood malignancies. Clinical features, histologic types, prognosis were very different from those seen in older children, facing oncologists with diagnostic, therapeutic and ethical problems.

PATIENTS AND METHODS

In a retrospective study from January 1987 to January 2004, we reviewed the management of neonates treated at the Institute Gustave Roussy for a malignant solid tumor for whom symptoms started in the first month of life.

RESULTS

Seventy-one neonates were treated, comprising 1,2% of the overall patients treated during the same period of time. Of these 71 patients, 42 (59%) presented with neuroblastomas, 12 (17%) with mesenchymal tumors, 6(8%) with cerebral tumors and 11 with various other types of tumors. Fifty-nine patients underwent surgical resection. Thirty-eight neonates received chemotherapy, administered at a 30 to 50% reduced dose. Hematologic toxicities and infections were the main therapeutic complications. Very small doses of radiotherapy were used in only 5 children. There has been no therapy-related mortality. Twenty-two of the 57 survivors have sequelae, especially patients with intraspinal neuroblastoma. The 5 year overall survival was 79%.

CONCLUSIONS

Neonatal malignant solid tumors, except for cerebral tumors, have a good prognosis. The young age of patients resulted in problems of treatment tolerance. The therapeutic regimen should take into account the risk of acute iatrogenic toxicity and long term sequelae. Surgery remains the treatment of choice but chemotherapy, with dose reduction, managed by expert teams, is essential and safer in a lot of case.

ETV6–NTRK3: a chimeric protein tyrosine kinase with transformation activity in multiple cell lineages

The ETV6-NTRK3 (TEL-TRKC) gene fusion was discovered by breakpoint analysis of the t(12;15)(p13;q25) translocation associated with congenital fibrosarcoma, a pediatric soft tissue malignancy. ETV6-NTRK3 (EN) encodes the sterile alpha motif oligomerization domain of the ETV6 (TEL) transcription factor linked to the protein tyrosine kinase domain of the neurotrophin-3 receptor NTRK3 (TRKC). The EN chimeric oncoprotein links to multiple signaling cascades including Ras-MAP kinase and PI3K-AKT through the IRS-1 adapter protein. Recent evidence indicates that a functional insulin-like growth factor 1 receptor axis and higher order polymer formation are essential for EN oncogenesis. EN has been detected in other malignancies, including secretory breast carcinoma. This chimeric oncoprotein is therefore unique in being expressed in tumors derived from multiple cell lineages.

Autosomal dominant inheritance of infantile myofibromatosis

We present three families with infantile myofibromatosis (IM; OMIM no. 228550) inherited in an autosomal dominant (AD) manner. These three pedigrees prompted re-assessment of pedigrees available within the genetic, oncologic, surgical, and pathologic literature, which suggest autosomal recessive (AR) inheritance. All familial IM may be interpreted as AD or, alternatively, there may be genetic heterogeneity for IM. As most nodules tend to regress spontaneously, familial history may be difficult to obtain and/or confirm. Clinical diagnosis and establishment of inheritance pattern can be important for prognosis and the recognition that other family members may be affected.

Infantile myofibromatosis: a cause of leg length discrepancy

An infant with self-healing, multifocal cutaneous infantile myofibromatosis with leg-length discrepancy as a sequela is reported. This condition should be suspected in infants with one or more firm or hard nodules in the skin, subcutaneous tissue, bone, muscle, or viscera. The histopathologic picture is diagnostic. Treatment and prognosis depend on the extension and location of the tumors.

ETV6-NTRK3 transformation requires insulin-like growth factor 1 receptor signaling and is associated with constitutive IRS-1 tyrosine phosphorylation

Congenital fibrosarcoma (CFS) and cellular mesoblastic nephroma (CMN) are pediatric spindle cell malignancies that share two specific cytogenetic abnormalities: trisomy of chromosome 11 and a t(12;15)(p13;q25) translocation. The t(12;15) rearrangement creates a transcriptionally active fusion gene that encodes a chimeric oncoprotein, ETV6-NTRK3 (EN). EN transforms NIH3T3 fibroblasts through constitutive activation of both the Ras-mitogen-activated protein kinase (MAPK) pathway and the phosphatidylinositol-3'kinase (PI3K)-Akt pathway. However, the role of trisomy 11 in CFS and CMN remains unknown. In this study we demonstrate elevated expression of the chromosome 11p15.5 insulin-like growth factor 2 gene (IGF2) in CFS and CMN tumors. Moreover, we present evidence that an intact IGF signaling axis is essential for in vitro EN-mediated transformation. EN only very weakly transformed so-called R-murine fibroblasts derived from mice with a targeted disruption of the IGF1 receptor gene (IGFRI), but transformation activity was fully restored in R- cells engineered to re-express IGFRI (R+ cells). We also observed that the major IGFRI substrate, insulin-receptor substrate-1 (IRS-1), was constitutively tyrosine phosphorylated and could be co-immunoprecipitated with EN in either R- or R+ cells expressing the EN oncoprotein. IRS-1 association with Grb2 and PI3K p85, which link IGFRI to the Ras-MAPK and PI3K-Akt pathways, respectively, was enhanced in both cell types in the presence of EN. However, activation of the Ras-MAPK and PI3K-Akt pathways was markedly attenuated in EN-expressing R- cells compared to EN-transformed R+ cells. This suggests that IRS-1 may be functioning as an adaptor in EN signal transduction, but that a link to EN transformation pathways requires the presence of IGFRI. Our findings indicate that an intact IGF signaling axis is essential for EN transformation, and are consistent with a role for trisomy 11 in augmenting this pathway in EN expressing tumors.

Effects of transforming growth factor-beta1 and tumour necrosis factor-alpha on cultured fibroblasts from skin fibroma as modulated by toremifene

To determine how toremifene, an anti-oestrogen triphenylethylene derivate, reduces tumour mass, we investigated its modulation of TGF-beta1 and TNF-alpha in fibroma fibroblasts. Normal and fibroma fibroblasts, isolated from patients affected by Gardner's syndrome without or with fibroma manifestation, were cultured in vitro. Secretion of GAG, collagen and TGF-beta1 was increased in fibroma fibroblasts compared to healthy cells. The increase in TGF-beta1 secretion into the medium was associated with a parallel increase in TGF-beta1 gene expression and receptor number. Receptor cross-linking studies using radiolabelled TGF-beta1 revealed more receptors, particularly types I and II, in fibroma fibroblasts than in normal cells. Normal and fibroma fibroblasts did not synthesise TNF-alpha, but they had TNF-alpha membrane receptors, as shown by TNF-alpha assay. TNF-alpha secreted by human monocytes, which may be present in the peritumoral area, increased cell proliferation and GAG accumulation and was, in turn, enhanced by TGF-beta1 treatment. Both growth factors increased angiogenesis, as shown by the CAM assay. Toremifene reduced TGF-beta1 secretion by fibroma fibroblasts and TNF-alpha secretion by monocytes, thus downregulating cell proliferation, ECM macromolecule accumulation and angiogenic progression. We hypothesise that increased TGF-beta1 gene expression and TGF-beta1 secretion in fibroma fibroblasts as well as the subsequent rise in TNF-alpha production by monocytes may facilitate fibroma growth and that toremifene inhibits autocrine and paracrine growth factor production.

Fibrosarcoma in pediatric patients: results of the Italian Cooperative Group studies (1979-1995)

BACKGROUND AND OBJECTIVES

Fibrosarcoma is a rare soft tissue sarcoma (STS) that has two peaks of incidence in pediatric patients: one in infants and young children (infantile fibrosarcoma), another in older children ("adult type" fibrosarcoma). The purpose of this study was to describe the clinical features and the treatment results in patients affected by fibrosarcoma enrolled in two consecutive studies run by the STS-Italian Cooperative Group (ICG) between 1979 and 1995.

PATIENTS AND METHODS

Twenty-five evaluable patients were grouped according the intergroup rhabdomyosarcoma staging (IRS) system: 12 Gr I, 5 Gr II, 8 Gr III. The cut-off point between the two forms was considered the age of 2 years: 14 patients were affected by infantile and 11 by adult type of fibrosarcoma. The therapeutic guidelines were not strict and not different for the two forms: patients with initial macroscopic excision (Gr I-II) were given IVA or VAC; Gr III had VAC or VAIA and subsequent excision, if feasible. Radiation therapy (RT) was delivered in patients > 3 years with microscopic (42 Gy) and macroscopic (54 Gy) residuals.

RESULTS

Thirteen patients are alive without evidence of disease: 10 in first complete remission (CR), 7 Gr I, 1 Gr II, 2 Gr III, 3 in second CR after local relapse (LR) (2 Gr I, 1 Gr II). Two Gr I patients are alive with metastatic relapse. Nine patients died: six of progressive disease (PD) (three Gr II, three Gr III), two because of a second tumor (one Gr I, one Gr III) and one because of other causes (Gr III). One Gr III patient was lost at follow up, 2 years from diagnosis. The 10 years overall survival (OS) is 67.4% and the progression-free survival (PFS) is 52.2%. The OS for patients < 2 years is 78.6% (11 of 14), versus 51% for patients > 2 years (5 of 11).

CONCLUSIONS

The complete excision at diagnosis was the treatment of choice and was related to the best outcome. Microscopical residuals were difficult to treat with chemo-radiotherapy in both forms of fibrosarcoma. Neoadjuvant chemotherapy (CT) obtained a partial remission (PR) only in three of eight cases, while no conclusions concerning the efficacy of CT for infantile forms are possible. Patients < 2 years had a better outcome than the older ones: most of them had a tumor on extremities which was excised at diagnosis.

Neonatal alveolar rhabdomyosarcoma with skin and brain metastases

BACKGROUND

Approximately 5-10% of patients with rhabdomyosarcomas (RMS) are diagnosed during the first year of life, and their clinical characteristics have been well documented. However, because RMS rarely occurs during the neonatal period, little is known about neonatal RMS.

METHODS

Four patients with neonatal RMS were treated at St. Jude Children's Research Hospital between 1962 and 1999. The authors report the results of a review of these patients and of cases described in the literature. Clinical, radiologic, and pathologic features of these patients and their outcomes were evaluated.

RESULTS

One patient with embryonal RMS was treated successfully with a combination of systemic chemotherapy and local control measures. The other three patients had alveolar RMS. Two of them had multiple skin and subcutaneous metastatic nodules at the time of diagnosis and developed brain metastases early in their course. In one of these patients, the PAX3-FKHR fusion transcript was detected. Three other similar cases of neonatal alveolar RMS with metastases to the skin and brain have been reported in the literature.

CONCLUSIONS

A distinct syndrome of neonatal RMS is described. This syndrome is characterized by alveolar histology, multiple skin and subcutaneous metastases, and fatal outcome as the result of early brain metastasis.

Aggressive CD34-positive fibrous scalp lesion of childhood: extrapulmonary solitary fibrous tumor

Although solitary fibrous tumor (SFT) was originally described as a pleural tumor, an increasing number of extrapleural sites of SFTs have been documented. This has been attributed not only to the heightened awareness of the spectrum of histopathological features that characterizes SFTs but also to the recognition of the role of CD34 immunostaining in soft tissue tumors in general, and in SFTs in particular. Despite the large number of documented extrapleural SFTs in adults, cranial SFTs are rare, having been documented in the meninges, scalp, and infratemporal fossa. Extrapleural SFTs are, to date, an unrecognized entity in children. We document an aggressive fibrous scalp lesion in a 30-month-old female child that demonstrated features common to benign cranial fasciitis and SFT. However, based on bright, diffuse CD34 antigen immunopositivity, a diagnosis of SFT was made. The need to include the CD34 antigen stain in a panel of immunohistochemical markers used to assess spindle cell lesions of childhood is emphasized.

Infantile myofibromatosis: case report of a solitary hand lesion with emphasis on differential diagnosis and management

Infantile myofibromatosis, both solitary and multicentric types, is discussed with emphasis on the importance of diagnosing this condition correctly. Its distinctive clinical and histological characteristics are described, as are the hazards of overhasty and overly ambitious surgical intervention. Other similarly presenting fibromatous diseases of infancy and childhood are discussed, including aplasia cutis, infantile fibrosarcoma, recurring infantile digital fibromatosis, and juvenile aponeurotic fibromatosis. A case of infantile myofibromatosis, solitary type, is reported, and the two surgical procedures carried out over a 4-year period are described. The importance of histological and immunohistochemical evaluation of lesions present during the neonatal period is stressed.

Congenital gastrointestinal stromal tumour is morphologically indistinguishable from the adult form, but does not express CD117 and carries a favourable prognosis

AIMS

The histological and immunohistochemical features of a congenital stromal tumour of the jejunum are compared with those of adult gastrointestinal stromal tumours (GIST). The literature concerning the diagnosis and prognosis of congenital small intestinal stromal tumours is reviewed.

METHODS AND RESULTS

A term female infant presented with intestinal obstruction, from birth. Histology of a 15-mm jejunal nodule showed a predominantly spindle-cell tumour with epithelioid areas. There was a low mitotic count and mild nuclear pleomorphism, extensive necrosis and haemorrhage, and focal calcification. Immunohistochemically, tumour cells stained for muscle specific actin and vimentin. Staining for CD117 (c-kit), S100, desmin and CD34 was negative. The features were compared to those of seven adult cases: no morphological feature was specific to the congenital tumour, which was smaller than the adult cases. There were no ultrastructural features specific for a particular line of differentiation. Immunohistochemical staining patterns were similar, except for CD117, which was strongly positive in all adult tumours, but negative in the congenital tumour.

CONCLUSIONS

This congenital jejunal stromal tumour morphologically resembled adult GIST, but lack of c-kit expression suggests that it is nosologically distinct. Despite the presence of histological features which would cause the tumour to be categorized as malignant in an adult, it is apparent from previous reports of congenital small intestinal stromal tumours that the prognosis is favourable.

Molecular detection of the ETV6-NTRK3 gene fusion differentiates congenital fibrosarcoma from other childhood spindle cell tumors

Congenital fibrosarcoma (CFS) is a pediatric spindle cell tumor of the soft tissues that usually presents before the age of 2 years. Although these tumors display histologic features of malignancy and frequently recur, they have a relatively good prognosis and only rarely metastasize. CFS must therefore be differentiated from more aggressive spindle cell sarcomas that occur during childhood, particularly adult-type fibrosarcoma (ATFS), which can have an identical morphology. CFS must also be distinguished from benign but cellular fibroblastic lesions of the same age group, including infantile fibromatosis (IFB) and myofibromatosis (MFB). Unfortunately, standard pathologic examination often does not differentiate CFS from these other conditions. The authors recently identified a novel chromosomal translocation in CFS, t(12;15)(p13;q25), which gives rise to an ETV6-NTRK3 gene fusion. They subsequently developed reverse transcription-polymerase chain reaction (RT-PCR) assays that can detect ETV6-NTRK3 fusion transcripts in CFS frozen or paraffin-embedded tumor specimens. To confirm the use of this assay in the differential diagnosis of CFS, they have screened a larger series of childhood pediatric spindle cell lesions for ETV6-NTRK3 gene fusions, including 11 cases of CFS, 13 malignant spindle cell tumors (including ATFS), and 38 benign spindle cell tumors (including IFB and MFB). Of the 11 cases diagnosed as CFS, 10 showed the ETV6-NTRK3 gene fusion, whereas none of the 51 other malignant or benign spindle cell tumors demonstrated this fusion gene. They also compared their RT-PCR findings with those of conventional cytogenetics and with immunohistochemical detection of the ETV6-NTRK3 protein using antisera to NTRK3. They conclude that RT-PCR analysis is superior to these techniques for the detection of the ETV6-NTRK3 gene fusion in pediatric spindle cell tumors, and it is a reliable and specific modality for the diagnosis of CFS.

Hemangiopericytoma in children and infants

BACKGROUND

Hemangiopericytoma (HPC) is a soft-tissue neoplasm most commonly seen in adults; only 5-10% of cases occur in children. Childhood HPC comprises two distinct clinical entities. In children older than 1 year, it behaves in a manner similar to adult HPC. Infantile HPC, however, although histologically identical to adult HPC, has a more benign clinical course. The reasons for these differences in the natural history of HPC are not well understood.

METHODS

The authors reviewed the clinicopathologic features of HPC as well as the treatment and outcomes of the 12 children (9 males and 3 females) treated for this disease at St. Jude Children's Research Hospital over a 35-year period.

RESULTS

At diagnosis, 9 patients were older than 1 year and 3 were younger than 1 year. Among the 9 older patients, tumors were most commonly found in the lower extremities (n = 5). One patient had been treated for acute lymphoblastic leukemia 15 years earlier. One patient had metastatic disease at diagnosis, and three had unresectable tumors. Two patients experienced objective responses to chemotherapy. Three patients died of disease progression. Among the three infants, two had unresectable disease at diagnosis, and both experienced excellent responses to neoadjuvant chemotherapy. In one case, the response of the tumor to chemotherapy correlated with maturation to hemangioma. All three infants are alive without evidence of disease.

CONCLUSIONS

HPC in children older than 1 year does not differ from adult HPC, and aggressive multimodality therapy is required. Infantile HPC, on the other hand, is characterized by better clinical behavior, with documented chemoresponsiveness and spontaneous regression, and requires a more conservative surgical approach. In some cases of infantile HPC, this benign behavior correlates with maturation to hemangioma.

Treatment of extra-abdominal desmoid tumors with interferon-alpha with or without tretinoin

BACKGROUND AND OBJECTIVES

Surgery is the main treatment for extra-abdominal desmoid tumors, but the results of further management remain uncertain. Therefore, a retrospective analysis was undertaken to evaluate the toxicity and efficacy of treatment with interferon-alpha (IFN-alpha) +/- tretinoin in this setting.

METHODS

Thirteen patients with extra-abdominal desmoid tumors and a median age of 32 years (range, 15-73) received IFN-alpha. Seven of these patients received a combination of IFN-alpha and tretinoin in order to test further enhancement.

RESULTS

After a mean observation period of 27 +/- 15 months (mean +/- standard deviation) under treatment with IFN-alpha +/- tretinoin, local control was seen in 11 of 13 patients (85%). Seven patients had no evidence of disease at a mean disease-free interval of 22 +/- 18 months; in two patients progressive disease occurred after only 7 and 9 months, respectively, of observation. In another four patients, progression of the desmoid tumor was stabilized.

CONCLUSIONS

The data of this retrospective, nonrandomized study on therapy with IFN-alpha +/- tretinoin suggest that such treatment may be effective in prolonging the disease-free interval of patients after intralesional or marginal surgery. Because of the encouraging response rate, this regimen appears to be another nonsurgical treatment alternative.

Current aspects of the pathology of soft tissue sarcomas

In soft tissue sarcomas, advances in pathological techniques, including immunohistochemistry, cytogenetics, and molecular genetics, have improved diagnostic accuracy, confirmed or clarified interrelationships between tumor subtypes, and revealed mechanisms of tumorigenesis. Many sarcomas are associated with abnormalities of tumor-suppressor genes, and several types have been found to have specific chromosomal translocations. These data and correlative clinicopathologic studies, although confirming many traditional pathological views, enable refinement or reassessment of terminology and classification of some small round cell, spindle cell, pleomorphic, and lipogenic tumors. New factors are emerging for prediction of tumor behavior, which might ultimately relate to therapy once a wider range of treatment options becomes available. This article reviews these current aspects of sarcoma pathology.

Fibrosarcoma of the trachea in a child: case report and review of the literature

We present a case of nearly total obstruction of the trachea in a 15-month-old boy suffering from tracheal fibrosarcoma. The diagnosis was confirmed on histological examination of a removed part of the tumor, with subsequent successful complete resection of tracheal fibrosarcoma. Follow-up to the age of 13 years showed complete recovery with normalization of respiratory functions. The diagnostic and therapeutic aspects of this case are discussed.

A novel ETV6-NTRK3 gene fusion in congenital fibrosarcoma

Congenital (or infantile) fibrosarcoma (CFS) is a malignant tumour of fibroblasts that occurs in patients aged two years or younger. CFS is unique among human sarcomas in that it has an excellent prognosis and very low metastatic rate. CFS is histologically identical to adult-type fibrosarcoma (ATFS); however, ATFS is an aggressive malignancy of adults and older children that has a poor prognosis. We report a novel recurrent t(12;15)(p13;q25) rearrangement in CFS that may underlie the distinctive biological properties of this tumour. By cloning the chromosome breakpoints, we show that the rearrangement fuses the ETV6 (also known as TEL) gene from 12p13 with the 15q25 NTRK3 neurotrophin-3 receptor gene (also known as TRKC). Analysis of mRNA revealed the expression of ETV6-NTRK3 chimaeric transcripts in all three CFS tumours analysed. These were not detected in ATFS or infantile fibromatosis (IFB), a histologically similar but benign fibroblastic proliferation occurring in the same age-group as CFS. ETV6-NTRK3 fusion transcripts encode the helix-loop-helix (HLH) protein dimerization domain of ETV6 fused to the protein tyrosine kinase (PTK) domain of NTRK3. Our studies indicate that a chimaeric PTK is expressed in CFS and this may contribute to oncogenesis by dysregulation of NTRK3 signal transduction pathways. Moreover, ETV6-NTRK3 gene fusions provide a potential diagnostic marker for CFS.