Active surveillance in desmoid-type fibromatosis: A systematic literature review.

BACKGROUND: This study evaluates the results of the active surveillance (AS) approach in adult patients with desmoid-type fibromatosis (DTF) because AS is advocated as a front-line approach for DTF in the European consensus guidelines. METHODS: A systematic literature search was conducted (December 19th, 2019, updated on April 14th, 2020). Studies describing the outcomes of the AS approach were included. The PRISMA guidelines were used. RESULTS: Twenty-five articles were included for data retrieval. Forty-two percent of reported patients (1480 of 3527 patients) received AS, the majority were women and the majority had a primary tumour. The median age at diagnosis ranged from 28 to 59 years. Common tumour sites were the extremities/girdles (n = 273), the abdominal wall (n = 253) and the trunk (n = 153). The median reported percentage of progressive disease, stable disease and partial response was 20% (interquartile range [IQR]: 13-35%), 59% (IQR: 37-69%) and 19% (IQR 3-23%), respectively. In 640 patients, the outcome was not specified. The median reported percentage of shifting to an active form of treatment was 29%, most commonly to systemic treatment (n = 195) and surgery (n = 107). The reported median follow-up time ranged between 8 and 73 months. The reported median time to progression and/or initiation of the subgroup shifting from AS to 'active' therapy ranged from 6.3 months to 19.7 months. CONCLUSION: The majority of patients undergoing AS have either stable disease or a partial response, and about one-third of patients shift to an active form of treatment. Selecting patients who will benefit from active surveillance upfront should be the priority of future studies.

PROMIS Function Scores Are Lower in Patients Who Underwent More Aggressive Local Treatment for Desmoid Tumors.

BACKGROUND: Desmoid tumors of the extremities often present with pain and functional limitation, but treatment can lead to morbidity and recurrence is common. The impact of treatment with respect to traditional "oncologic" metrics (such as recurrence rate) has been studied extensively, with a shift in recent years away from local therapies as first-line management; however, little is known about the association between treatment modality and long-term functional outcomes for patients with this benign disease. QUESTIONS/PURPOSES: In a retrospective review of consecutive patients treated at two institutions, we asked: (1) Is event-free survival (EFS) different between patients who undergo local treatment and those who do not for primary as well as for recurrent desmoid tumors? (2) What treatment-related factors are associated with worse Patient-reported Outcomes Measurement Information System (PROMIS) function scores at a minimum of 1 year after treatment? METHODS: Between 1991 and 2017, 102 patients with desmoid tumors of the extremities (excluding those of the hands and feet) were treated at two institutions; of those, 85 patients with 90 tumors were followed clinically for at least 1 year (median [range] 59 months follow-up [12 to 293]) and were included in the present analysis. We attempted to contact all patients for administration of PROMIS function (Physical Function Short Form [SF] 10a and Upper Extremity SF v2.0 7a) and Pain Interference (SF 8a) questionnaires. Complete survey data (minimum 1 year follow-up) were available for 46% (39 of 102) of patients with 40 tumors at a median of 125 months follow-up; only these patients were included in PROMIS data analyses. Though there was no formal institutional treatment algorithm in place during the study period, surgical resection typically was the preferred modality for primary tumors; radiation therapy and systemic treatments (including cytotoxic or hormonal agents earlier in the study period, and tyrosine kinase inhibitors later) were often added for recurrent or very symptomatic disease. We coded treatment for each patient into discrete episodes, each defined by a particular treatment strategy: local treatment only (surgery and/or radiation), systemic treatment only, local plus systemic treatment, or observation; treatment episodes rendered at other institutions (that is, before referral) were not included in the analyses. Treatment failure was defined as recurrence after surgical resection, or clinically significant radiologic and/or symptomatic progression after systemic treatment, and EFS was defined as time from treatment initiation to treatment failure or final follow-up. Episodes of treatment for recurrent tumors were analyzed in a pooled fashion, wherein discrete treatment episodes for patients with multiple recurrences were included separately as independent events. We analyzed 56 primary tumors (54 patients), and 101 discrete treatment episodes for recurrent tumors (88 patients). Kaplan-Meier survival curves were constructed separately for the primary and recurrence cohorts, both comparing EFS among patients who received any local treatment (local treatment and local plus systemic treatment groups) versus those who did not (systemic treatment and observation groups). PROMIS function data were analyzed on the bases of patient- and treatment-specific variables, including the PROMIS Pain Interference score as a potential explanatory variable. RESULTS: Within both the primary and recurrence cohorts, there were no differences between the local treatment, systemic treatment, and local plus systemic treatment groups with respect to gender, age, axillary/hip girdle location, or tumor volume. Among primary tumors, 5-year EFS was 44% (95% CI 24 to 80) for the systemic-only group versus 15% (95% CI 5 to 44) for the local treatment group (p = 0.087). Within the pooled recurrence treatment episode cohort, 5-year EFS after systemic-only treatment was 70% (95% CI 52 to 94) versus 56% among patients receiving any local treatment (95% CI 44 to 70; p = 0.46). PROMIS function scores were lowest among patients who underwent two or more resections (39 versus 51 versus 47 for ≥2, 1, and 0 resections, respectively; p = 0.025); among those who received both surgery and radiation at any point, either concurrently or in separate treatment episodes, as compared with those who did not (39 versus 46; p = 0.047); and among those with higher levels of pain interference (38 versus 47 for pain interference scores > 50 versus < 50; p = 0.006). CONCLUSIONS: Patients treated with local modalities (surgery and/or radiation, with or without additional systemic therapy) did not experience improved EFS as compared with those treated without local modalities; this was the case for both the primary and the recurrent tumor cohorts. However, PROMIS function scores were lowest among patients who underwent two or more surgical interventions and among those treated with surgery and radiation at any time, suggesting that more aggressive local treatment may be associated with poorer long-term functional outcomes. Prospective collection of patient-reported outcomes data at multiple time points will allow for more direct correlations between treatment modality and impact on function and will help to elucidate the ideal management strategy for these benign but often-symptomatic tumors. LEVEL OF EVIDENCE: Level III, therapeutic study.

Enhanced T-lymphocyte infiltration in a desmoid tumor of the thoracic wall in a young woman treated with intratumoral injections of the oncolytic peptide LTX-315: a case report.

BACKGROUND: Desmoid tumors are intermediary malignant, fibrous lesions occurring in various soft tissues. Surgical treatment is relentlessly challenging because of the propensity for local aggressive behavior and high risk of recurrence. Consequently, a wide range of oncological drugs and radiation therapy are being used; however, outcomes are unpredictable. We investigated whether local treatment with an oncolytic peptide could be beneficial in a patient with an unresectable desmoid tumor. CASE PRESENTATION: In a young 29-year-old Caucasian woman who was diagnosed with a retromammary desmoid tumor infiltrating deeply into the anterior thoracic wall, surgery was considered excessively mutilating, and observation was recommended. The lesion progressed, however, and caused debilitating pain, despite nonsteroidal anti-inflammatory medication. Subcutaneous injections of human interferon-α (Multiferon®) resulted in reduced growth kinetics but had to be terminated because of development of symptomatic pneumonitis. Frequently used oncological treatment was withheld because of the toxicity profile, and the patient was instead included in a phase I study investigating transdermal intratumoral injection of LTX-315, an oncolytic peptide that induces anticancer immune responses ( ClinicalTrials.gov , NCT01986426 ). A marked increase of CD8+ tumor-infiltrating T cells in the lesion was complemented by upregulation of immune gene signature (including effector T-cell, T-helper type 1 cell, chemokine, and cytokine genes). These changes were followed by gradual symptom relief and long-term disease stabilization, indicating clinical benefit. LTX-315 was well tolerated until termination in week 16 after a serious allergic reaction. CONCLUSIONS: Our patient was treated with repeated intratumoral injections of LTX-315, resulting in tumor regression accompanied by upregulation of immune genes and T-cell infiltration. Local application of immunotherapy, minimizing systemic side effects, represents a novel treatment modality in desmoid tumors that should be tested in further clinical trials.

Improving thermal dose accuracy in magnetic resonance-guided focused ultrasound surgery: Long-term thermometry using a prior baseline as a reference.

PURPOSE: To investigate thermal dose volume (TDV) and non-perfused volume (NPV) of magnetic resonance-guided focused ultrasound (MRgFUS) treatments in patients with soft tissue tumors, and describe a method for MR thermal dosimetry using a baseline reference. MATERIALS AND METHODS: Agreement between TDV and immediate post treatment NPV was evaluated from MRgFUS treatments of five patients with biopsy-proven desmoid tumors. Thermometry data (gradient echo, 3T) were analyzed over the entire course of the treatments to discern temperature errors in the standard approach. The technique searches previously acquired baseline images for a match using 2D normalized cross-correlation and a weighted mean of phase difference images. Thermal dose maps and TDVs were recalculated using the matched baseline and compared to NPV. RESULTS: TDV and NPV showed between 47%-91% disagreement, using the standard immediate baseline method for calculating TDV. Long-term thermometry showed a nonlinear local temperature accrual, where peak additional temperature varied between 4-13°C (mean = 7.8°C) across patients. The prior baseline method could be implemented by finding a previously acquired matching baseline 61% ± 8% (mean ± SD) of the time. We found 7%-42% of the disagreement between TDV and NPV was due to errors in thermometry caused by heat accrual. For all patients, the prior baseline method increased the estimated treatment volume and reduced the discrepancies between TDV and NPV (P = 0.023). CONCLUSION: This study presents a mismatch between in-treatment and post treatment efficacy measures. The prior baseline approach accounts for local heating and improves the accuracy of thermal dose-predicted volume.

Desmoid-Type Fibromatosis of the Thorax: CT, MRI, and FDG PET Characteristics in a Large Series From a Tertiary Referral Center.

The purpose of this study was to describe the radiologic findings of computed tomography (CT), magnetic resonance (MR) imaging, and ¹8F-fluorodeoxy glucose positron emission tomography (FDG PET) in desmoid-type fibromatosis of the thorax. We retrospectively evaluated 47 consecutive patients with pathologically proven desmoid-type fibromatosis from January 2005 to March 2015. Patients underwent CT (n = 36) and/or MR (n = 32), and 13 patients also underwent FDG PET. Based on CT and MR, the sizes, locations, margins, contours, presence of surrounding fat, extra-compartment extension, bone involvement, and neurovascular involvement of the tumors were recorded. The attenuation, signal intensity, enhancement pattern, and presence of internal low signal band or signal void of the tumors were evaluated. Initial image findings were then compared between 2 groups of tumors: group 1 with recurrence or progression, and group 2 with no recurrence or stable without treatment. Median age at diagnosis of the tumors was 45 years, range 4 to 96, female-to-male ratio 1.8. Median tumor long diameter was 65 mm (range, 22-126 mm). The most common locations were chest wall (42.6%), followed by supraclavicular area, shoulder or axillary area, and mediastinum. The tumors had well-defined margins (83.0%), lobulated in contours (66.0%) surrounding fat (63.8%), extra-compartment extensions (42.6%), bone involvements (42.6%), and neurovascular involvements (27.7%). On CT, tumors had low attenuation (60.0%) with mild enhancement (median 24 HU, range 0-52). On MR, they showed iso-signal intensity (SI) (96.9%) on T1-weighted images (WI), and high SI (90.6%) on T2WI images, with strong (87.5%) and heterogeneous (96.9%) enhancement. Internal low signal bands (84.4%) and signal voids (68.8%) were noted. The median value of maxSUV was 3.1 (range, 2.0-7.3). In group 1 (n = 19, 40.4%), 13 patients suffered recurrence and 6 experienced progression. Group 2 (n = 28, 59.6%) consisted of 21 patients with no recurrence and 7 stable patients receiving no treatment. Partially ill-defined margins (OR, 0.167; 95% CI 0.029-0.943; P = 0.043) was the independent predictor for recurrence or progression of tumor. Knowledge of the radiological findings in desmoid-type fibromatosis on CT, MR, and FDG PET may help to improve diagnosis. Tumors with partially ill-defined margins have a tendency to recur or progress.

Near universal detection of alterations in CTNNB1 and Wnt pathway regulators in desmoid-type fibromatosis by whole-exome sequencing and genomic analysis.

CTNNB1 mutations or APC abnormalities have been observed in ∼85% of desmoids examined by Sanger sequencing and are associated with Wnt/ß-catenin activation. We sought to identify molecular aberrations in "wild-type" tumors (those without CTNNB1 or APC alteration) and to determine their prognostic relevance. CTNNB1 was examined by Sanger sequencing in 117 desmoids; a mutation was observed in 101 (86%) and 16 were wild type. Wild-type status did not associate with tumor recurrence. Moreover, in unsupervised clustering based on U133A-derived gene expression profiles, wild-type and mutated tumors clustered together. Whole-exome sequencing of eight of the wild-type desmoids revealed that three had a CTNNB1 mutation that had been undetected by Sanger sequencing. The mutation was found in a mean 16% of reads (vs. 37% for mutations identified by Sanger). Of the other five wild-type tumors sequenced, two had APC loss, two had chromosome 6 loss, and one had mutation of BMI1. The finding of low-frequency CTNNB1 mutation or APC loss in wild-type desmoids was validated in the remaining eight wild-type desmoids; directed miSeq identified low-frequency CTNNB1 mutation in four and comparative genomic hybridization identified APC loss in one. These results demonstrate that mutations affecting CTNNB1 or APC occur more frequently in desmoids than previously recognized (111 of 117; 95%), and designation of wild-type genotype is largely determined by sensitivity of detection methods. Even true CTNNB1 wild-type tumors (determined by next-generation sequencing) may have genomic alterations associated with Wnt activation (chromosome 6 loss/BMI1 mutation), supporting Wnt/ß-catenin activation as the common pathway governing desmoid initiation.

Pregnancy does not increase the local recurrence rate after surgical resection of desmoid-type fibromatosis.

BACKGROUND: Pregnancy has been reported as a risk factor for promoting growth and progression of desmoid-type fibromatosis because of the presumed role of estrogens in stimulating desmoid growth. In this study, the clinical outcomes of females who were pregnant 5 years or less before resection of desmoid tumor or who became pregnant after resection were compared to nulliparous females or females who were pregnant more than 5 years before resection. METHODS: Obstetric histories of desmoid tumor patients were abstracted from medical records. Patients were grouped by pregnancy status as either: pregnancy-associated (pregnant up to 5 years before primary desmoid tumor resection or pregnant after resection) or not pregnancy-associated (nulliparous or pregnant more than 5 years before resection of desmoid tumor). Cox proportional hazards regression was used to evaluate pregnancy status as a predictor of desmoid tumor recurrence. RESULTS: There were 15 females who had pregnancy-associated desmoids (33%) and 31 females who had non-pregnancy-associated desmoids (67%). There were no differences in clinicopathologic features or recurrence-free survival between females of different pregnancy status in univariate or multivariate survival analyses. CONCLUSION: Recurrence-free survival rates among women recently pregnant before or pregnant after resection of desmoid tumor and nulliparous women or those with a remote history of pregnancy are comparable after adjusting for patient age, anatomic location, and completeness of surgical resection. Subsequent pregnancy should not be discouraged for reproductive-aged women after resection of desmoid-type fibromatosis.

Cardiac failure due to a giant desmoid tumour of the posterior mediastinum.

We report a rare case of a giant desmoid tumour responsible for cardiac and respiratory failure. Complete removal was decided upon, despite an initial failure in another centre because of symptom severity. In such cases, wide local resection remains the best therapeutic approach, but the risk of local recurrence is high. Literature review confirms the exceptional presentation and the benefit of aggressive surgery.

[Surgical treatment of desmoid fibroma and sarcoma of the thoracic and abdominal wall].

The article analyses the 17-year (1993-2009 yy) experience of surgical treatment of desmoid fibroma and sarcoma of the thoracic and abdominal wall. 46 operations were analyzed. The radical excision according to the principles of surgical oncology remains the mainstay in the treatment of such patients. The combined technique with the use of polymeric implantates allows to cover large wall defects, thus extending the operability borders and being one of the main factors of the better treatment prognosis.

Desmoid tumor of posterior cruciate ligament of the knee: a case report.

BACKGROUND: Desmoid tumor is a rare type of cancer that develops in the tissues that form tendons and ligaments. These tumors, also called aggressive fibromatosis, are considered benign with no metastatic potential. They may invade nearby tissues and organs, however, and can be difficult to control. Desmoid tumor in the posterior cruciate ligament (PCL) of the knee has never been described in the literature. CASE PRESENTATION: A 49-year-old man presented with a 2-month history of posteromedial knee dull pain and decreased range of motion of the knee. He was diagnosed desmoid tumor of posterior cruciate ligament of the knee by intraoperative biopsy, and underwent successful PCL resection and reconstruction by Four-strand semitendinosus and gracilis tendon autograft arthroscopically, and fortunately five years after operation, there were no clues as to recurrence of the tumor examined by Magnetic Resonance Imaging (MRI). CONCLUSION: Desmoid tumor is characterized by infiltrative growth and a tendency towards recurrence,as this tumor entity is rare, data giving evidence based recommendations for the optimal treatment algorithm for this disease is lacking. At present there is no definite and effective method of treatment. However, early detection of the tumor play an important role, MRI is now the most important method for the detection of tumor extent, which facilitates the treatment choice as well as the prediction of prognosis. In our case, we followed-up the patient five years postoperatively by MRI and got a good result.

La Radiología y el efecto mariposa / No disponible

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[Agressive fibromatosis: genetic and biological correlations]. / Agresívna fibromatóza: geneticko-biologické korelácie.

Aggressive fibromatosis, also known as desmoid tumor, is specific and relatively rarely occuring disease. It belongs to heterogenous group of soft tissue tumors. Originally, it arises from fibroblasts with monoclonal proliferation derived from fibro-aponeurotic tissue with typical local invasive spreading without metastatic tendency. Increased amount of knowledge about the role of the APC gene and its protein product in FAP play an important role in revealing the molecular nature of desmoid tumors. In general, we can conclude that the ß-catenin dysregulation is the key player of the FAP associated desmoid tumor onset. The Wingless/Wnt cascade plays a crucial role in the pathogenesis of aggressive fibromatosis. However, it has not been definitely proven that the mutations of APC or ß-catenin genes are the trigger mechanisms. The research outcome can pave the way for using target biological therapy in routine practice in patients with aggressive fibromatosis in the future.

Management of brachial plexus region tumours and tumour-like conditions: relevant diagnostic and surgical features in a consecutive series of eighteen patients.

BACKGROUND: Tumours of the brachial plexus region are rare and most publications are case reports or studies with a small series of patients. The aim of this study is to present our experience in managing these lesions. METHODS: We review 18 patients with tumours in the brachial plexus region submitted to surgical treatment in a 6 year period, including their clinical presentation, neuro-imaging data, surgical findings and outcome. FINDINGS: The tumours comprised a heterogeneous group of lesions, including schwannomas, neurofibromas, malignant peripheral nerve sheath tumour (MPNST), sarcomas, metastases, desmoids and an aneurysmal bone cyst. The most common presentation was an expanding lump (83.33%). Eleven tumours were benign and 7 were malignant. Neurofibromatosis was present in only 2 patients (11.11%). Gross total resection was achieved in 14 patients and sub-total resection in the others. Only 3 patients presented with new post-operative motor deficits. The incidence of complications was low (16.5 %). CONCLUSIONS: The majority of tumours were benign and most of them could be excised with a low incidence of additional deficits. Some of the malignant tumours could be controlled by surgery plus adjuvant therapy, but this category is still associated with high morbidity and mortality rates.

Desmoid cell motility is induced in vitro by rhEGF.

Desmoid tumors are benign but locally invasive myofibroblastic lesions that arise predominantly in the abdominal wall or shoulder and are prone to aggressive local recurrences. A perceived association between desmoid activity and the expression of growth factors during pregnancy or following trauma suggests a cause-and-effect relationship between growth factor stimulation and desmoid invasiveness. We used Boyden Chambers to quantify cell motility in order to determine the effect of growth factor stimulation on desmoid cell migration. Desmoid cell cultures were treated under serum-free conditions with epidermal growth factor (rhEGF) or transforming growth factor alpha (rhTGFalpha). Additional cell cultures were pretreated under serum-free conditions with the EGF receptor (EGFR) inhibitor AG1478, alone or in combination with the TGFbeta1 receptor inhibitor SB431542, and then stimulated with growth factor prior to being assayed for cell motility. The experiments demonstrated a direct dose-dependent relationship between rhEGF stimulation and desmoid motility. In contrast, rhTGFalpha was less effective at inducing cell migration. rhEGF-induced cell migration could be diminished, but not reduced to control levels, by inhibiting EGFR. When EGF and TGFbeta1 receptors were inhibited simultaneously, the level of rhEGF-induced cell migration was reduced significantly beyond the level of cell migration generated by inhibition of EGFR alone.

Juvenile hyaline fibromatosis and infantile systemic hyalinosis: divergent expressions of the same genetic defect?

We describe here a three year-old girl with classic clinical and histological features of juvenile hyaline fibromatosis. We found a history of similar skin findings in her eldest sister, in whom the disorder took a rapidly progressive and fatal course in the second year of life, suggesting either a very severe form of juvenile hyaline fibromatosis, or the possibility of infantile systemic hyalinosis. The similarities and differences between these two described types of hyalinoses have been reviewed in reference to the present report.

Desmoid tumor: a disease opportune for molecular insights.

Desmoid tumors are monoclonal proliferations that fall within a broad histologic spectrum of fibrous mesenchymal tumors that ranges from benign proliferations of scar tissue to high-grade fibrosarcomas. These low-grade tumors are extremely infiltrative locally, but lack the ability to metastasize systemically. While they are only rarely a direct cause of mortality, using current therapeutic modalities, these tumors have a high rate of local recurrence that can result in significant treatment related morbidity. Sporadic desmoids are usually associated with somatic mutations in codons 41 or 45 of exon 3 of beta-catenin (CTNNB1). Desmoid tumors occurring in the background of familial adenomatous polyposis (FAP) usually contain inactivating germline mutations in the adenomatous polyposis coli (APC) gene. CTNNB1 and APC are part of the Wnt signaling pathway and mutations in either gene result in stabilization of the beta-catenin protein and allow nuclear translocation and binding of beta-catenin to the T-cell factor/lymphoid enhancer factor (TCF/Lef) family of transcription factors, resulting in activation of target genes which may underlie desmoid tumor biology and clinical behavior. In an era of molecularly targeted therapeutics there is a real need to better grasp the molecular mechanisms behind desmoid tumorigenesis and progression. This knowledge will eventually result in the development of patient and tumor tailored therapies and assist in the control and eradication of this disease.

[Rating of tumoral growth in non-operated primary or recurrent extra-abdominal aggressive fibromatosis]. / Etude de la croissance tumorale des tumeurs desmoïdes extra-abdominales (FDEA) primitives ou récidivées non opérées.

PURPOSE OF THE STUDY: Extra-abdominal aggressive fibromatosis (EAAF) is a benign desmoid tumor with a potentially aggressive behavior. Surgical treatment is compromised by a very high rate of recurrence, sometimes with significant morbidity. We conducted a prospective surveillance of our patients (clinical and MRI) with EAAF to search for prognostic factors. MATERIAL AND METHODS: This cohort included 17 patients with EAAF. For nine patients, biopsy alone was performed. For eight, the tumor was a recurrence after surgical removal. Patients were seen for a clinical assessment and MRI every six months. RESULTS: Median follow-up was 42 months (range 6-114). Three patients worsened clinically with pain or functional impairment. One patient required neurosurgery to control pain (good stable outcome). MRI showed progression for two tumors (12%) but with a short follow-up since diagnosis (9 and 14 months), in one case despite medical treatment. Three tumors regressed and twelve remained stable on successive MRI. On average the tumor growth lasted ten months. DISCUSSION: Tumor growth was never noted beyond 36 months. This notion of an interruption in tumor growth is mentioned sporadically in reports on EAAF, which have generally included recurrent tumors. To our knowledge this is the first series reporting tumors left in place a followed with modern imaging techniques. The high rate of spontaneous interruption of tumor growth must be counterbalanced with the difficult task of local treatment: the risk of recurrence is particularly high after surgery and functional sequelae can be significant when wide resection is proposed in an anatomically difficult localization. The precise role for surgery, and combined radiotherapy, remain to be determined. There are only scarce reports on general treatments. Considering these facts, we propose that surgical resection should not be considered the only solution for the treatment of EAAF. Further work is needed to define the useful contribution of simple surveillance of these benign tumors.

Desmoid and fibroma tumors differently respond to TGFbeta(1) 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.