Familial infiltrative fibromatosis (desmoid tumours) (MIM135290) caused by a recurrent 3' APC gene mutation

Mesenchymal tumours of the pleura: review and update

Primary mesenchymal tumours of the pleura are uncommon and can be diagnostically challenging due to their overlapping histopathologic and immunophenotypic features. Herein we discuss selected mesenchymal tumours of the pleura, including solitary fibrous tumour, calcifying fibrous tumour, desmoid fibromatosis, synovial sarcoma, schwannoma, malignant peripheral nerve sheath tumour, inflammatory myofibroblastic tumour, follicular dendritic cell sarcoma, epithelioid hemangioendothelioma, and desmoplastic small round cell tumour. We review their clinicopathologic characteristics, along with an update on the relevant immunohistochemical and molecular features.

CD36 polymorphisms and the age of disease onset in patients with pathogenic variants within the mutation cluster region of APC

Background

Familial adenomatous polyposis (FAP) is an autosomal dominant condition that predisposes patients to colorectal cancer. FAP is the result of a loss of APC function due to germline pathogenic variants disrupting gene expression. Genotype-phenotype correlations are described for FAP. For example attenuated forms of the disease are associated with pathogenic variants at the 5’ and 3’ ends of APC whilst severe forms of the disease appear to be linked to variants occurring in the mutation cluster region (MCR) of the gene. Variants occurring in the MCR are phenotypically associated with hundreds to thousands of adenomas carpeting the colon and rectum and patients harbouring changes in this region have a high propensity to develop colorectal cancer. Not all patients who carry pathogenic variants in this region have severe disease which may be a result of environmental factors. Alternatively, phenotypic variation observed in these patients could be due to modifier genes that either promote or inhibit disease expression. Mouse models of FAP have provided several plausible candidate modifier genes, but very few of these have survived scrutiny. One such genetic modifier that appears to be associated with disease expression is CD36. We previously reported a weak association between a polymorphism in CD36 and a later age of disease onset on a relatively small FAP patient cohort.

Methods

In the current study, we enlarged the FAP cohort. 395 patients all carrying pathogenic variants in APC were tested against three CD36 Single Nucleotide Polymorphisms (SNP)s (rs1049673, rs1761667 rs1984112), to determine if any of them were associated with differences in the age of disease expression.

Results

Overall, there appeared to be a statistically significant difference in the age of disease onset between carriers of the variant rs1984112 and wildtype. Furthermore, test equality of survivor functions for each SNP and mutation group suggested an interaction in the Log Rank, Wilcoxon, and Tarone-Ware methods for rs1049673, rs1761667, and rs1984112, thereby supporting the notion that CD36 modifies disease expression.

Conclusions

This study supports and strengthens our previous findings concerning CD36 and an association with disease onset in FAP, AFAP and FAP-MCR affected individuals. Knowledge about the role CD36 in adenoma development may provide greater insight into the development of colorectal cancer.

APC mosaicism in a young woman with desmoid type fibromatosis and familial adenomatous polyposis

Familial adenomatous polyposis (FAP) is usually caused by germline mutations in the adenomatous polyposis coli (APC) gene. The classic form is characterized by hundreds to thousands of adenomas in the colorectum and early onset colorectal cancer (CRC) if left untreated. FAP is also associated with multiple extra-colonic manifestations such as gastroduodenal polyps, osteomas, epidermoid cysts, fibromas and desmoids. Most desmoid tumours in FAP patients occur intra-abdominally. Approximately 15–20% of the APC mutations are de novo mutations. Somatic mosaicism has been reported in some sporadic cases of polyposis but is probably an underestimated cause of the disease. This case report presents the detection of a mosaic APC mutation in a 26-year-old woman who as a child had been diagnosed with desmoid type fibromatosis. FAP was suggested when she presented with extensive extra abdominal fibromatosis. Our findings indicate that APC mutations may be suspected in patients presenting with a desmoid regardless of its location. If there is clinical evidence that the patient has FAP, adenomas and colonic mucosa in addition to leukocyte DNA should be included in the screening, preferably using methods that are more sensitive than Sanger sequencing.

From Gardner fibroma diagnosis to constitutional APC mutation detection: a one-way street

We report a young child without a family history of FAP, who promptly underwent APC testing after the histological confirmation of a paraspinal GAF that was not isolated. Our case report reinforces the suggestion advanced by previous authors for an APC analysis in all patients with GAF.

Biology and Treatment of Aggressive Fibromatosis or Desmoid Tumor

Aggressive fibromatosis, also known as desmoid-type fibromatosis (DTF) or desmoid tumor, is an uncommon locally invasive tumor. Because of its low incidence and variable behavior, DTF is often first seen by physicians who are not familiar with it, and recent advances in understanding this disease have led to changes in treatment approaches. The Wnt (β-catenin) pathway appears to play a key role in DTF pathogenesis, and recent studies of DTF biology suggest a possible model of DTF pathogenesis. Histologically, DTF shows a poorly circumscribed proliferation of myofibroblast-like cells with variable collagen deposition, similar to the proliferative phase of wound healing, and DTF has been associated with trauma and pregnancy. Desmoid-type fibromatosis may be a useful model of the tumor stroma in carcinomas as well as other fibrosing diseases such as progressive pulmonary fibrosis. The clinical course of DTF can vary greatly among patients, complicating the determination of the optimal treatment approach. Treatment options include surgery, nonsteroidal anti-inflammatory drugs with or without hormonal manipulation, chemotherapy, radiation therapy, and other forms of local therapy. Many treatments have been used, but these are not without toxicities. Because of the variable nature of the disease and the potential morbidity of treatment, some cases of DTF may do better without treatment; simple observation is often the best initial treatment. This review used a PubMed search from January 1, 1980, through October 31, 2016, using the terms fibromatosis and desmoid and discusses DTF disease characteristics, pathophysiology, and treatment options as well as examines several cases illustrating key points in the biology and treatment of this heterogeneous disease.

Clinical Activity of the γ-Secretase Inhibitor PF-03084014 in Adults With Desmoid Tumors (Aggressive Fibromatosis)

Purpose Desmoid tumors (aggressive fibromatosis) arise from connective tissue cells or fibroblasts. In general, they are slow growing and do not metastasize; however, locally aggressive desmoid tumors can cause severe morbidity and loss of function. Disease recurrence after surgery and/or radiation and diagnosis of multifocal desmoid tumors highlight the need to develop effective systemic treatments for this disease. In this study, we evaluate objective response rate after therapy with the γ-secretase inhibitor PF-03084014 in patients with recurrent, refractory, progressive desmoid tumors. Patients and Methods Seventeen patients with desmoid tumors received PF-03084014 150 mg orally twice a day in 3-week cycles. Response to treatment was evaluated at cycle 1 and every six cycles, that is, 18 weeks, by RECIST (Response Evaluation Criteria in Solid Tumors) version 1.1. Patient-reported outcomes were measured at baseline and at every restaging visit by using the MD Anderson Symptoms Inventory. Archival tumor and blood samples were genotyped for somatic and germline mutations in APC and CTNNB1. Results Of 17 patients accrued to the study, 15 had mutations in APC or CTNNB1 genes. Sixteen patients (94%) were evaluable for response; five (29%) experienced a confirmed partial response and have been on study for more than 2 years. Another five patients with prolonged stable disease as their best response remain on study. Patient-reported outcomes confirmed clinician reporting that the investigational agent was well tolerated and, in subgroup analyses, participants who demonstrated partial response also experienced clinically meaningful and statistically significant improvements in symptom burden. Conclusion PF-03084014 was well tolerated and demonstrated promising clinical benefit in patients with refractory, progressive desmoid tumors who receive long-term treatment.

Primary and recurrent sporadic desmoids: Prognostic factors influencing recurrence-free survival after complete gross resection

INTRODUCTION

There is continuing controversy over the significance of prognostic factors in sporadic desmoid-type fibromatosis (DF). Further, only limited data is available in the literature concerning second recurrence in patients with recurrent DF. The purpose of this study was to identify prognostic factors influencing recurrence-free survival (RFS) and to determine rates of local recurrence (LR) in patients with primary and recurrent DF.

METHODS

Fifty-three consecutive patients with DF who underwent surgery at a single institution were identified. As a result of strict exclusion criteria, a homogeneous cohort of thirty-two patients who received macroscopically complete resection was included in this study and split into a primary (PG) and recurrent disease (RG) group. Clinicopathological parameters and immunohistochemical markers were retrospectively and independently analyzed in both groups.

RESULTS

The local recurrence rate was 35% for the PG and 33% for the RG. The PG's calculated median time to relapse was 17 months, and the RG's was 29 months. The estimated 1-, 5-, and 8-year RFS rates for the PG were 75%, 64%, and 55% while the corresponding RFS rates for the RG were 69%, 69%, and 52%, respectively. In primary disease, extraabdominal tumor location was the only significant adverse prognostic factor associated with worse RFS (p = 0.008). Whereas in recurrent disease, age ≥40 yrs (p = 0.022) and R0 margin status (p = 0.049) correlated with a significantly better outcome.

CONCLUSION

Recurrence in primary and recurrent DF is characterized by different predictive factors and benefits from distinct therapeutic strategies. Immunohistochemical markers are valuable tools in the diagnosis of DF, although have limited potential in predicting the outcome.

The medico-legal observation of an aggressive urogenital fibromatosis with isolated development not related to any traumatic event

Desmoid tumor is a fibroproliferative neoplasm with an intermediate malignancy and it can be localized in every bodily district: some locations are considered exceptional, like the urogenital localization. The Author point out a rare case of giant idiopathic scrotal fibromatosis that was found during an autopsy. A widower, that lived alone in poor hygienic conditions, was found dead in his house. The Judicial Authority ordered the autopsy, that was performed two days later at the Medico-Legal Section of Milan University. External examinations revealed only the considerable dimension of the scrotum (cm 24 × 41). The cause of death was fixed in a cardiac tamponade due to a natural heart laceration localized in correspondence of a transmural infarction. The toxicological exam resulted negative, while the histopathological and immunohistochemical analysis qualify the scrotal mass as a desmoids tumor. Due to the absence of predisposing conditions and of fibroproliferative infiltration in bladder and retroperitoneal space, the neoplasm was configured as an idiopathic desmoid tumor. The presented case gives the reason for the discussion concerning medico-legal aspects that are typical of rare neoplasms.

Desmoid tumor patients carry an elevated risk of familial adenomatous polyposis

BACKGROUND

The prevalence of desmoid tumors among patients with familial adenomatous polyposis (FAP) is at least 10%, and the prevalence of FAP among desmoid patients varies between 7.5-16%.

METHODS

Data included 106 desmoid patients identified from the database of the Department of Pathology, Helsinki University Hospital, years 2000-2012. We evaluated the risk of FAP among patients by using endoscopy and we identified individuals with attenuated FAP by APC gene mutation test. We compared sporadic desmoid patients' and FAP patients' clinical characteristics.

RESULTS

Ten of 106 patients already had FAP diagnosis before the desmoid. Eleven patients had had FAP screening already earlier due to desmoid and three of them were found to have FAP. Total of 52 patients participated into prospective screening of FAP. No new cases of FAP were found. The risk of FAP among desmoid tumor patients was 4.8%. In the FAP desmoid group, there were more males and patients were younger than in the sporadic group. Intra-abdominal desmoids were more common in the FAP group.

CONCLUSIONS

Patients with desmoid carry an elevated risk of FAP and therefore screening is indicated. Asymptomatic patients with desmoid situated in extra truncal region may not need to be screened.

Desmoids and genotype in familial adenomatous polyposis

BACKGROUND

Desmoid disease can be a serious, life-threatening complication of familial adenomatous polyposis. The ability to predict patients at increased desmoid risk is important, but a convincing genotype-phenotype correlation for desmoid formation has not yet been described.

PURPOSE

The aim of this study is to assess the relationship between desmoid disease and genotype in patients with familial adenomatous polyposis.

DESIGN

This is a cohort study.

PATIENTS

All patients with familial adenomatous polyposis and a documented pathogenic APC mutation in themselves or a first-degree relative were selected.

MAIN OUTCOMES MEASURES

The comparison of genotype and the presence, stage, and site of desmoid disease are the primary end points of this study.

RESULTS

Three hundred twenty-three patients from 219 families were identified. Mutations spanned the length of the gene, from codon 213 to codon 2051. Desmoid disease was diagnosed in 77 patients from 68 families. Desmoid disease was found in 14.9% of patients with a mutation 5' of codon 400, 23.2% of patients with a mutation from codon 401 to 1400, and in 37.1% of those with a mutation 3' of 1400. All patients with 5' mutations had stage I or II abdominal desmoid disease, and all tumors were stable or shrinking. Twelve percent of patients who had desmoid disease with mutations between codons 400 and 1400 had stage III or IV desmoid disease, and 5 of 42 (12%) tumors were growing at the time of the study. There had been 2 desmoid-related deaths. Almost half (44%) of patients who had desmoid disease with mutations 3' of codon 1400 had stage III or IV disease. Three of 14 tumors were growing (21%), and there were 4 desmoid-related deaths.

LIMITATIONS

This study was conducted at a tertiary referral center, and there was no systematic surveillance for desmoids.

CONCLUSION

Desmoid disease occurs in patients who have familial adenomatous polyposis with almost any APC mutation, although there is an increased propensity in those with a 3' mutation. The incidence and severity of the desmoid disease are related to the site of the mutation.

Attenuated familial adenomatous polyposis with desmoids caused by an APC mutation

We present here a case of attenuated familial adenomatous polyposis (AFAP) with a family history of desmoids and thyroid tumors. This patient had no colonic polyps but did have multiple desmoids. Genetic analysis identified a 4-bp deletion in codon 2644 (c.7932_7935delTTAT: p.Tyr2645LysfsX14) of the adenomatous polyposis coli (APC) gene. In cases with limited numbers of colonic polyps and desmoids, AFAP may be caused by a mutation in the 3′ region of APC.

Is wide resection obsolete for desmoid tumors in children and adolescents? Evaluation of histological margins, immunohistochemical markers, and review of literature

Desmoid fibromatosis is a benign fibroblastic neoplasm with high recurrence rates predominantly observed in pediatric and adolescent patients. The use of wide resection margins has been discussed controversially in literature. In addition, data on non-surgical treatment is limited as phase III studies are still missing. Nineteen patients under the age of 18 years were identified. Tumor location, surgical treatment for primary or recurrent tumors, resection margins, medical neo-/adjuvant treatment, time to recurrence as well as immunohistochemical markers (estrogen receptor, ER α and β, progesterone and androgen receptors, somatostatin, Ki-67, c-kit, platelet-derived growth factor receptors, PDGFRs, α and β, β-catenin) were evaluated. The mean age at diagnosis was 6.6 years, with a mean follow-up of 114 months. Recurrences were detected in four out of nineteen patients. Surprisingly, the recurrence rate was not influenced by type of resection used (R0, R1/2). All samples were tested negative for ER α, somatostatin, and progesterone receptor. In contrast, a majority of tumors showed positive results for PDGFR α and β and β-catenin. No correlation between positive immunohistochemical markers and tumor recurrences was detectable. In conclusion, recurrence rates are not depending on resection type and immunohistochemical markers seem to behave differently in children and adolescents in contrast to adult patients.

Clinical characteristics and adequate treatment of familial adenomatous polyposis combined with desmoid tumors

Purpose

The objective of this study was to examine the clincopathologic characteristics and outcomes of familial adenomatous polyposis (FAP) patients with and without desmoid tumors (DTs), including the risk factors for progression of FAP-related DTs.

Materials and Methods

We reviewed the medical records and database of all patients with FAP who were treated between January 1993 and December 2011.

Results

Of 75 FAP patients, 18 (24%) were FAP with DTs. Seventeen of these had intra-abdominal DTs and one had intra- and extra-abdominal DTs. We divided the patients into two groups according to type of resection; the R0 or R1 resection group, referred to as the curative resection group (eight patients), and the R2 resection/palliative operation/medical treatment group, referred to as the palliative resection group (10 patients). Two patients in the curative resection group and two patients in the palliative group had progressed to tumor growth by the follow-up (p=0.800). In univariate analysis, DT diagnosis before or simultaneously with FAP diagnosis (DTs unrelated to surgical trauma) was a significant risk factor for tumor progression at final follow-up.

Conclusion

A multidisciplinary approach to DT treatment is needed, including nonsteroidal antiinflammatory drugs, anti-estrogens, cytotoxic agents, and surgery. However, the role of surgery in resectable and complicated tumors may be limited. DT unrelated to surgical trauma has a relatively poor prognosis.

Attenuated familial adenomatous polyposis manifests as autosomal dominant late-onset colorectal cancer

Colorectal cancer (CRC) risk is well defined for families of patients with classical familial adenomatous polyposis (FAP). However, the risk for those with an attenuated form of FAP is less well characterised. In this study, we estimated CRC risks for carriers of a novel germline mutation in the APC gene that causes attenuated FAP (AFAP). We performed genetic testing on 53 individuals from seven AFAP families harbouring an identical APC:c.288T>A mutation. Using a modified segregation analysis, we estimated relative and absolute CRC risks for mutation carriers. Twenty-three individuals harboured the disease causing mutation. CRC occurred in 28 individuals (mean 61.7 years, range 32-80 years). The estimated CRC relative risks for mutation carriers aged 60-69 and ≥70 years were 19 (95% CI: 1.77-204.08) and 45 (95% CI: 11.32-180.10), respectively, while the absolute CRC lifetime risk for men was 94% (95% CI: 67.5-99.9%), and for women, 84% (95% CI: 50.9-99.0%). This study shows that AFAP can manifest as autosomal dominant late-onset CRC. These findings highlight a subgroup of inherited CRCs that require new criteria for identification and surveillance.

Multicentric synchronous recurrent aggressive fibromatosis

Extra-abdominal desmoid tumors are known as aggressive fibromatosis (AFM). Synchronous and metachronous multicentric aggressive fibromatosis are rare lesions and pose dilemma in diagnosis and management. A rare and interesting case of recurrent multicentric, synchronous AFM is presented which to the best of our knowledge has not been reported earlier. A young male presented with well defined, hard, fixed swelling on the thigh. Resected tumor mass on histopathology was diagnosed as an extra abdominal fibromatosis. He presented again after two months with swelling at the same site; and two more swellings on the foot. Fine needle aspiration cytology (FNAC) from all three sites was performed; and was suggestive of benign spindle cell lesion of fibrogenic origin with the possibility of multicentric synchronous recurrent aggressive fibromatosis.

Evaluation of guidelines for management of familial adenomatous polyposis in a multicenter pediatric cohort

OBJECTIVE

To retrospectively assess, in a pediatric multicenter cohort, guidelines for the management of familial adenomatous polyposis (FAP).

METHODS

Ten centers from the French-speaking Pediatric Gastroenterology Hepatology and Nutrition Group provided follow-up data on patients up to 18 years of age. Clinical records, genetic test results, endoscopy with histopathology examination, and therapeutic modalities were reviewed.

RESULTS

A total of 70 children from 47 families were included. When initial consultation resulted from a surveillance program because of an affected family member, 12 of 59 children were already symptomatic. Among 11 patients whose initial consultation was based only on symptoms, families were unaware at the time of a familial FAP history for 7 children, whereas only 4 cases were sporadic. A panel of 27 different pathogenic adenomatous polyposis coli (APC) germ-line mutations and large genomic deletions were identified in 43 families. Extracolonic manifestations were found in half of the patients. As part of the standard practice for initial screening, the entire cohort underwent colonoscopy, which revealed adenoma above an intact rectosigmoid in 8 cases. Prophylactic colectomy was performed in 42 cases; high-grade dysplastic adenoma and 1 invasive carcinoma were detected in 6 children. For timing of surgery, indications were in accordance with recent international guidelines.

CONCLUSIONS

Defining optimal screening and therapeutic modalities in pediatric FAP cohorts is a challenge. Specific advice for genetic screening, endoscopy surveillance, and type of surgery based on recent guidelines is recommended.

Aggressive fibromatosis (desmoid tumor) is derived from mesenchymal progenitor cells

The cellular origins from which most tumors arise are poorly defined, especially in mesenchymal neoplasms. Aggressive fibromatosis, also known as desmoid tumor, is a locally invasive soft tissue tumor that has mesenchymal characteristics. We found that aggressive fibromatosis tumors express genes and cell surface markers characteristic of mesenchymal stem cells (MSC). In mice that are genetically predisposed to develop aggressive fibromatosis tumors (Apc(wt/1638N)), we found that the number of tumors formed was proportional to the number of MSCs present. Sca-1(-/-) mice, which develop fewer MSCs, were crossed with Apc(wt/1638N) mice. Doubly mutant mice deficient in Sca-1 developed substantially fewer aggressive fibromatosis tumors than wild-type (WT) littermates, but Sca-1 deficiency had no effect on the formation of epithelial-derived intestinal polyps. MSCs isolated from Apc(wt/1638N) mice (or mice expressing a stabilized form of β-catenin) induced aberrant cellular growth reminiscent of aggressive fibromatosis tumors after engraftment to immunocompromised mice, but WT cells and mature fibroblasts from the same animals did not. Taken together, our findings indicate that aggressive fibromatosis is derived from MSCs, and that β-catenin supports tumorigenesis by maintaining mesenchymal progenitor cells in a less differentiated state. Protecting this progenitor cell population might prevent tumor formation in patients harboring a germline APC mutation, where fibromatosis is currently the leading cause of mortality.

Colonic adenomatous polyposis syndromes: clinical management

Colorectal cancer is one of the major causes of cancer deaths in both men and women. It is estimated that 5 to 10% of patients with colorectal cancer have an inherited germline mutation that predisposes them to cancer. Hereditary colorectal cancer syndromes can be divided into those associated with colonic polyposis - familial adenomatous polyposis (FAP), attenuated familial adenomatous polyposis (aFAP), and MYH associated polyposis (MAP), and those not associated with colonic polyposis - hereditary nonpolyposis colon cancer (HNPCC). The hereditary polyposes are usually easier to diagnose than HNPCC, but their higher penetrance and variable phenotype pose some difficult problems in management and surveillance. The timing and type of surgical intervention, the management of desmoid risk, the treatment of rectal or pouch neoplasia, and the management of duodenal neoplasia are all questions that must be addressed in patients with FAP or MAP.

Three novel mutations of the APC gene in Korean patients with familial adenomatous polyposis

Germline mutations within the adenomatous polyposis coli (APC) gene are associated with familial adenomatous polyposis (FAP), an autosomal dominant disease predisposing individuals to colorectal cancer. Identification of APC mutations has important implications for genetic counseling and management of FAP patients. We examined the APC mutation status of 10 Korean FAP patients by polymerase chain reaction-direct sequencing method and found six APC mutations, including three novel mutations. Testing for MUTYH mutation was done for FAP patients in whom no mutation in the APC gene was identified. Three novel mutations (c.1654_1663delTCTTGGCGAG, c.3709C>T, and c.6092_6094delinsTT) and three previously reported mutations (c.3631_3632delAT, c.4438C>T, and c.4612_4613delGA) were detected. The MUTYH mutation was not detected in any of the four FAP patients without an APC mutation. This finding of three novel mutations in a group of Korean FAP patients broadens the spectrum of APC mutations.

Clinical outcomes of systemic therapy for patients with deep fibromatosis (desmoid tumor)

BACKGROUND

In the current study, the authors examined the outcomes of patients with desmoid tumors who received systemic therapy at a single institution to provide a basis for the examination of newer agents.

METHODS

Records of patients with desmoid tumors who were treated with chemotherapy at the study institution were reviewed. The activity of nonsteroidal anti-inflammatory drugs was not addressed. Patients without measurable disease and those receiving therapy could not be documented, and those receiving prophylactic therapy were excluded.

RESULTS

A total of 68 patients received 157 lines of therapy. At the time of last follow-up, 9 patients had died, 7 of progressive disease. The cohort was 62% female, with a median age of 32.5 years. Approximately 32% of the patients had Gardner syndrome. The median follow-up was 63 months, and patients received a median of 2 lines of therapy. An intra-abdominal primary tumor location was the most common (44%). The greatest Response Evaluation Criteria in Solid Tumors (RECIST) response rate was observed with anthracyclines and hormonal therapy and the lowest response was noted with single-agent dacarbazine/temozolomide or tyrosine kinase inhibitors, principally imatinib. On multivariate analysis, macroscopic nodular morphology and the presence of Gardner syndrome were the only tumor factors found to be associated with a greater time to disease progression.

CONCLUSIONS

Compared with other agents, antiestrogens and anthracycline-containing regimens appear to be associated with a higher radiological response rate against desmoid tumors. Systemic therapy can be successful in patients with desmoid tumors, and is a viable option in lieu of morbid or disabling surgery.

Beta-catenin expression in pediatric fibroblastic and myofibroblastic lesions: a study of 100 cases

Nuclear immunoreactivity for beta-catenin is a useful adjunct for diagnosis of adult desmoid-type fibromatoses, many of which exhibit mutations within the APC/beta-catenin (Wnt) pathway. Pediatric fibromatoses represent a heterogeneous group of lesions that are diagnostically challenging, especially on biopsy. We studied beta-catenin expression in a variety of pediatric fibroblastic and myofibroblastic lesions. Immunohistochemical nuclear expression of beta-catenin was assessed in 100 tumors. High-level expression of beta-catenin was found in 42% of usual-type or deep fibromatoses (21 of 50). Such expression was not seen in any of the other lesions, including fibrous hamartoma of infancy (0 of 18), juvenile hyaline fibromatosis (0 of 7), infantile digital fibromatosis (0 of 6), myofibromatosis (0 of 5), lipofibromatosis (0 of 4), calcifying aponeurotic fibroma (0 of 3), palmar-plantar fibromatosis (0 of 2), fibromatosis colli (0 of 1), or torticollis (0 of 1). High-level beta-catenin staining is seen in deep "adult-type" fibromatoses occurring in children, although to a lesser frequency than in adult fibromatoses. This indicates that a subset of deep fibromatoses in childhood shares similar mechanisms of tumorigenesis with those in adults. beta-catenin is not expressed in other common pediatric fibroblastic and myofibroblastic lesions, and the Wnt pathway does not appear to play a role in their pathogenesis.

The role of APC and beta-catenin in the aetiology of aggressive fibromatosis (desmoid tumors)

BACKGROUND

Aggressive fibromatosis (syn. desmoid tumor) is a sporadically occurring neoplastic proliferation of fibroblasts originating from musculoaponeurotic planes, forming invasively growing masses without the capability to metastasize. The choice of treatment remains surgical resection with or without radiotherapy, and is characterized by high recurrence rates. Better understanding of the aetiology of aggressive fibromatosis is needed to be able to develop new treatment strategies to cope with the high recurrence rates.

METHODS

Relevant studies were identified through a search of the electronic databases PubMed/ Medline. The following search terms were used: 'aggressive fibromatosis', 'desmoid tumor', 'adenomatous polyposis coli', 'APC', 'beta-catenin', 'Wnt', 'Wingless' and 'Wnt/Wingless'. Studies were selected for review on the basis of abstract reading. A hand search was performed by checking reference lists in selected articles.

RESULTS

The neoplastic nature of aggressive fibromatosis and the role of the adenomatous polyposis coli (APC) and beta-catenin signaling cascade in driving the onset and progression of this disease are discussed.

CONCLUSION

Mutations in either the APC or beta-catenin genes are likely to be a major driving force in the formation of these desmoid tumors. More research is needed to develop new treatment strategies.

Desmoid tumors in a dutch cohort of patients with familial adenomatous polyposis

BACKGROUND & AIMS

Desmoid tumors are a severe extracolonic manifestation in familial adenomatous polyposis (FAP). Identification of risk factors might be helpful in the management of FAP patients with such tumors. The aim of this study was to assess potential risk factors for the development of desmoids in a cohort of Dutch FAP patients.

METHODS

The medical records of 735 FAP patients were analyzed for the occurrence of desmoids. Relative risks and survival times were calculated to assess the influence of potential risk factors (female sex, family history, mutation site, abdominal surgery, and pregnancy) on desmoid development.

RESULTS

Desmoid tumors were identified in 66 of the 735 patients (9%). The cumulative risk of developing desmoids was 14%. No correlation was found between specific adenomatous polyposis coli mutation sites and desmoid development. Patients with a positive family history for desmoids had a significant increased risk to develop this tumor (30% vs 6.7%, P < .001). No association was found between female sex or pregnancy and desmoid development. Most desmoid patients (95%) had undergone previous abdominal surgery. In a substantial proportion of patients with an ileorectal anastomosis, it was impossible to convert the ileorectal anastomosis to an ileal pouch-anal anastomosis as a result of desmoid development.

CONCLUSIONS

A positive family history of desmoids is an evident risk factor for developing desmoids. Most desmoids develop after colectomy. No correlation was found between desmoids and the adenomatous polyposis coli gene mutation site, female sex, and pregnancy. Ileal pouch-anal anastomosis is the appropriate type of surgery in FAP patients with a positive family history for desmoids.

Detection of beta-catenin mutations in paraffin-embedded sporadic desmoid-type fibromatosis by mutation-specific restriction enzyme digestion (MSRED): an ancillary diagnostic tool

Desmoid-type fibromatosis is a locally aggressive deep soft tissue tumor. Some cases are associated with adenosis polyposis coli germline mutations whereas others harbor somatic beta-catenin point mutations mainly in exon 3, codons 41 and 45. These mutations result in stabilization of beta-catenin, and activation of the Wnt signaling pathway. The aim of this study was to determine the specificity and sensitivity of these 3 most common beta-catenin mutations in the diagnosis of desmoid-type fibromatosis using paraffin-embedded material. The results were compared with nuclear expression of beta-catenin. Mutation-specific restriction enzyme digestion methodology was employed to detect the 3 mutations. One hundred and thirty-three cases were analyzed, including 76 desmoid-type, and 18 superficial fibromatosis, in addition to a further 39 fibromatosis mimics. A restriction site was present for analysis of the codon 41 mutation. Mismatch primers were designed for the codon 45 mutations. Mutations were detected in 66 cases (87%) of 76 desmoid-type fibromatosis (71 extra-abdominal). Of these, 34 (45%) were in codon 45 (TCT>TTT), 27 (35%) in codon 41 (ACC>GCC), and 5 (7%) in codon 45 (TCT>CCT). No mutations were detected in the other lesions studied. All desmoid-type fibromatosis cases and 72% of the mimics tested showed nuclear positivity for beta-catenin indicating immunohistochemistry is a sensitive but not a specific test for desmoid-type fibromatosis. In contrast, to date, beta-catenin mutations have not been detected in any lesions which mimic desmoid-type fibromatosis. Mutation-specific restriction enzyme digestion, a simple and efficient means of detecting the common beta-catenin mutations in desmoid-type fibromatosis, complements light microscopy in reaching a diagnosis.

Does early colectomy increase desmoid risk in familial adenomatous polyposis?

BACKGROUND & AIMS

Desmoid tumors are non-metastasizing fibromatoses that occur in 10%-20% of subjects with familial adenomatous polyposis (FAP). Intra-abdominal desmoid tumors are a major cause of mortality in FAP. FAP-associated desmoid tumors are linked to trauma, particularly abdominal surgery, family history of desmoids, hormonal factors, and the location of the APC mutation. We hypothesized that prophylactic colectomy at an early age might increase the risk of developing desmoids. The aim of this study was to determine whether colectomy earlier in life is a risk factor for the development of desmoid tumors.

METHODS

An analysis was made of the association between development of desmoid and age at colectomy, family history of desmoids, gender, and APC mutation in FAP patients in the Registry (1980-2005) at Mount Sinai Hospital, Toronto, Ontario, Canada.

RESULTS

FAP patients (n = 930) from 365 kindreds were identified. Desmoid prevalence was 14% (n = 121). Female patients were more likely to develop desmoids than male patients (17% vs 11%, P = .03). Female patients who had an early colectomy were more than 2 times more likely to develop a desmoid, compared with women who had a colectomy at >18 years (P = .01). Early colectomy did not increase risk of developing a desmoid in male patients (P = .42). Female patients who had an early colectomy (</=18 years) were 2.5 times more likely to develop desmoids, compared with male patients who had a late colectomy (P = .05). The prevalence of desmoids in the 5' and 3' groups was 13% and 38%, respectively (P = .0005). Patients with a mutation after codon 1399 were found to have 4 times greater chance of developing a desmoid.

CONCLUSIONS

Female patients with FAP are more likely to develop desmoids than male patients. Female patients who had an early colectomy are at significantly greater risk of developing a desmoid compared with female patients who had a colectomy in adulthood. Patients with APC mutations beyond codon 1399 are more likely to develop desmoids. These results suggest that delayed colectomy might be considered in young female patients with FAP to decrease the chances of developing desmoids.

Desmoid tumours in patients with familial adenomatous polyposis and desmoid region adenomatous polyposis coli mutations

BACKGROUND

:The aim of this study was to determine the proportion of patients with familial adenomatous polyposis (FAP) who had mutations in the desmoid region of the adenomatous polyposis coli (APC) gene that phenotypically expresses desmoid disease, and to determine the role for surgery in these patients.

METHODS

Data from the North West Region FAP database and case notes were analysed retrospectively.

RESULTS

Of 363 patients with FAP, 47 from ten families had APC mutations in the desmoid region 3' to codon 1399. Of 22 patients undergoing surgery, 16 developed desmoids, and of these 12 had mesenteric desmoid disease. Complications from mesenteric desmoids were death (two patients), enterectomy (three), local resection (three), fistula (one), cholangitis and local resection (one), bowel obstruction (one) and bowel and ureteric obstruction (one). Preoperative polyp burden ranged from 0 to 100 in eight patients (median age 24.5 (range 16-39) years) and more than 100 in seven (median age 39 (range 31-64) years). One patient had no record of polyp burden.

CONCLUSION

In individuals with 3' APC mutations, abdominal surgery is associated with a 65 per cent risk of developing mesenteric desmoids. An alternative strategy might be to attempt to manage the polyps endoscopically.

3' Mutation of the APC gene and family history of FAP in a patient with apparently sporadic desmoid tumors

Desmoid tumors may occur sporadically or as part of the extraintestinal manifestations of familial adenomatous polyposis. Different phenotypes have been described and some genotype-phenotype correlations have been raised, associated with different sites of germline mutations in the adenomatous polyposis coli (APC) gene. We report on a 42-year-old woman ascertained for a large desmoid tumor of the anterior chest wall with pleural involvement, which persistently recurred despite a decade of treatment including hormone therapy, chemotherapy, and surgery. Spontaneous disappearance of the tumor was later noted after 1 year without any treatment and confirmed after 4 years of regular follow-up. Repeated colonoscopies were normal in the proband and DNA sequencing showed a frameshift mutation due to a single adenosine deletion at position 5772 (codon 1924). This mutation, located in the exon 15 at the 3' end of the APC gene, leads to an unusual and late onset phenotype. The pedigree revealed other isolated or familial adenomatous polyposis-associated cases of desmoid tumors. This family report shows that a molecular analysis of the APC gene should be performed in familial desmoid tumors for accurate genetic counseling and follow-up.

Correlations between mutation site in APC and phenotype of familial adenomatous polyposis (FAP): A review of the literature

Mutations in the adenomatous polyposis coli (APC) gene cause familial adenomatous polyposis (FAP). Disease severity and the presence of extracolonic manifestations seem to be correlated with the location of the mutation on the APC gene. In this review, large studies describing genotype-phenotype correlations in FAP were evaluated and categorized. Attenuated FAP (AFAP, <100 colorectal adenomas) is correlated with mutations before codon 157, after codon 1595 and in the alternatively spliced region of exon 9. Severe polyposis (>1000 adenomas) is found in patients with mutations between codons 1250 and 1464. Mutations in the remainder of the APC gene cause an intermediate phenotype (hundred to thousands of adenomas). Congenital hypertrophy of the retinal pigment epithelium (CHRPE) and desmoid tumours are associated with mutations between codons 311 and 1444 and after codon 1444, respectively. No consistent correlations were found for upper gastrointestinal tumours. Genotype-phenotype correlations in FAP will be useful in decisions concerning screening and surgical management of FAP.

Current ideas in desmoid tumours

Desmoid tumours are rare neoplasms of fibroblastic origin which arise with disproportionate frequency in patients with familial adenomatous polyposis (FAP). They are thought to develop in about 10-25% of FAP patients and may be the leading cause of death amongst those who have undergone colectomy. Risk factors include trauma, having a distal germline APC mutation, having a family history of desmoids, and probably oestrogens. In very high-risk individuals there may be a case for delay of colectomy or chemoprophylaxis at the time of surgery. Desmoids are now known to be true neoplasms but with normal telomere length and telomerase activity. FAP-associated tumours seem to carry biallelic APC mutations, one of which lies in the distal part of the gene. Such loss of wild-type APC seems to occur relatively late in tumour development. It is likely that beta-catenin plays an important role in tumourigenesis. FAP-associated desmoids tend to arise in the abdomen or abdominal wall. CT scanning gives the best information on tumour anatomy whilst T2-weighted MRI indicates likely behaviour. Treatment may simply consist of observation. Otherwise, usual first-line therapy is with sulindac with or without an anti-oestrogen. Cytotoxic chemotherapy is an option in unresectable tumours. Surgery is a reasonable first-line treatment in abdominal wall tumours but is risky for intra-abdominal tumours and may necessitate massive small bowel resection. Desmoids are the greatest remaining challenge in the management of FAP and further research into their aetiology needs to be combined with multicentre clinical trials of new treatments in order to improve management of the disease.

An association between the 4G polymorphism in the PAI-1 promoter and the development of aggressive fibromatosis (desmoid tumor) in familial adenomatous polyposis patients

Aggressive fibromatosis is a mesenchymal neoplasm associated with mutations resulting in beta-catenin mediated transcriptional activation. Plasminogen activator inhibitor-1 (PAI-1) is expressed at a high level in aggressive fibromatosis, and using transgenic mice, we found that PAI-1 plays an important role in aggressive fibromatosis tumor formation. Familial adenomatous polyposis is associated with Adenomatous Polyposis Coli gene mutations resulting in beta-catenin mediated transcriptional activation, yet only some patients develop aggressive fibromatosis. Since PAI-1 expression is influenced by a promoter 4G/5G polymorphism, we investigated the incidence of this polymorphism in familial adenomatous polyposis patients who did and who did not develop aggressive fibromatosis, as well as sporadic aggressive fibromatosis patients. There was a trend towards association of the 4G allele (associated with high PAI-1 expression) with the development of aggressive fibromatosis in familial adenomatous polyposis patients (50% vs. 19%, P = 0.1). In familial adenomatous polyposis patients who did not develop aggressive fibromatosis, there was a significantly lower proportion of patients with a 4G allele compared to the healthy control (19% vs. 51%, P = 0.0286). The lower incidence of 4G polymorphism in the PAI-1 promoter may be preventive against the development of aggressive fibromatosis. This data provides additional evidence supporting an important role for PAI-1 in the pathogenesis of aggressive fibromatosis.

APC mutations in FAP-associated desmoid tumours are non-random but not ‘just right’

Analysis of APC mutations in colonic and duodenal tumours from familial adenomatous polyposis (FAP) patients has shown that the site of the first hit, the germline mutation, can predict the type and position of the somatic mutation or 'second hit'. The two APC mutations are selected on the basis of a 'just right' level of beta-catenin signalling in intestinal tumours achieved through retention of some of the seven 20-amino-acid beta-catenin degradation repeats. Desmoids are a life threatening extra-colonic manifestation in FAP patients. These aggressive tumours of mesenchymal origin are, at present, poorly characterized in terms of mutational APC spectra. We have investigated somatic mutations in the largest cohort of FAP-associated desmoids to date, and combined our results with previously published data. Somatic mutations were found to occur non-randomly and the position of the germline mutation shown to be a major determinant of the somatic mutation, a characteristic shared with intestinal tumours from FAP patients. In contrast to colonic polyps, loss of heterozygosity in desmoids involved deletion rather than mitotic recombination. While tumours from the colorectum and upper gastrointestinal tract usually retain one to two and three to four beta-catenin degradation repeats, respectively, most desmoids preferentially retain two repeats (P < 0.001, chi2 test). In addition, most desmoids with two APC hits (87%, 26/30) had one mutated allele with no 20-amino acid repeats (P < 0.001). This feature, unique among FAP tumours, indicates that a mutation deleting all repeats from one allele may be an important component in maintaining appropriate levels of beta-catenin signalling levels in desmoid tumour cells.

Genetic predisposition to colorectal cancer: new pieces in the pediatric puzzle

Colorectal cancer is rare in childhood. The 2 best characterized familial syndromes, hereditary nonpolyposis colorectal cancer (HNPCC, Lynch syndrome) and familial adenomatous polyposis (FAP), are autosomal dominant inherited disorders. HNPCC is relevant to pediatric gastroenterology practice because children and adolescents with underlying colorectal cancer can have germ-line mutations of mismatch repair genes. Recent attention has focused on characterizing genetic predisposition to attenuated FAP in individuals who do not have germ-line mutations in the APC gene. The identification of a second mechanistic explanation called MYH-associated polyposis (MAP), which is an autosomal-recessive condition, has important implications for both screening and management strategies. Hereditary colorectal cancer including HNPCC, FAP, attenuated FAP and MYH-associated polyposis in children are the subject of this review.

From the archives of the AFIP: benign fibrous tumors and tumorlike lesions of the mesentery: radiologic-pathologic correlation

Mesenteric fibromatosis, sclerosing mesenteritis, inflammatory pseudotumor, and extrapleural solitary fibrous tumor constitute a loosely associated group of benign fibrous tumors and tumorlike lesions of the mesentery. These lesions are linked histologically by the presence of fibroblasts or fibrosis and anatomically by their location within the mesentery. Although rare, and distinctly different in pathogenesis and biologic behavior, these fibrous lesions have pathologic and radiologic features that overlap with one another and with more common neoplastic and nonneoplastic lesions of the mesentery. Mesenteric fibromatosis is a locally aggressive, benign proliferative process that may occur sporadically or in association with familial adenomatous polyposis. It most frequently manifests as a focal mesenteric mass and may simulate lymphoma, metastatic disease, or a soft-tissue sarcoma. Sclerosing mesenteritis is a rare idiopathic disorder that most commonly produces a stellate mass within the mesentery and should be differentiated from metastatic disease, specifically metastatic carcinoid, because it frequently responds to conservative or medical management. Inflammatory pseudotumor (inflammatory myofibroblastic tumor) is a benign, chronic inflammatory disorder of unknown cause that manifests as a solid mesenteric mass, indistinguishable from malignancy. Extrapleural solitary fibrous tumor is a tumor of submesothelial origin that is identical to the solitary fibrous tumor of the pleura. When located in the mesentery or peritoneal cavity, extrapleural solitary fibrous tumor has an imaging pattern that must be differentiated from metastatic disease, soft-tissue sarcomas, and other benign and malignant neoplasms of the mesentery and peritoneum. Knowledge of this group of benign fibrous tumors and tumorlike lesions of the mesentery is important in the preoperative evaluation of a mesenteric mass.

Desmoid tumor in Gardner's Syndrome presented as acute abdomen

Background

Gardner's syndrome can occasionally be complicated with intra-abdominal desmoid tumor. These tumors usually remain asymptomatic but can exhibit symptoms due to intestinal, vascular and ureteral compression and obstruction.

Case presentation

A rare case of a 41-year-old male patient with Gardner's syndrome complicated with intra-abdominal desmoid tumor, which first presented as acute abdomen, is presented.

Conclusion

Extra-abdominal manifestations of Gardner's syndrome along with a palpable abdominal mass would raise suspicion for the presence of a desmoid tumor in the majority of cases. In life-threatening cases, surgical treatment should be considered as a palliative approach, though the extent of excision remains debatable

A gene expression signature that distinguishes desmoid tumours from nodular fasciitis

Nodular fasciitis (NF) is a rapidly growing cellular mass composed of fibroblasts/myofibroblasts, usually localized in subcutaneous tissues, that typically undergoes fibrosis and almost never recurs. Desmoid tumours (DTs) are rare forms of fibroblastic/myofibroblastic growth that arise in deep soft tissues, display a propensity for local infiltration and recurrence, but fail to metastasize. Given that both entities are primarily fibroblastic/myofibroblastic lesions with overlapping histological features, their gene expression profiles were compared to identify differentially expressed genes that may provide not only potential diagnostic markers, but also clues as to the pathogenesis of each disorder. Differentially expressed transcripts (89 clones displaying increased expression in DTs and 246 clones displaying increased expression in NF) included genes encoding several receptor and non-receptor tyrosine kinases (EPHB3, PTPRF, GNAZ, SYK, LYN, EPHA4, BIRC3), transcription factors (TWIST1, PITX2, EYA2, OAS1, MITF, TCF20), and members of the Wnt signalling pathway (AXIN2, WISP1, SFRP). Remarkably, almost one-quarter of the differentially expressed genes encode proteins associated with inflammation and tissue remodelling, including members of the interferon (IFN), tumour necrosis factor (TNF), and transforming growth factor beta (TGF-beta) signalling pathways as well as metalloproteinases (MMP1, 9, 13, 23), urokinase plasminogen activator (PLAU), and cathepsins. The observations provide the first comparative molecular characterization of desmoid tumours and nodular fasciitis and suggest that selected tyrosine kinases, transcription factors, and members of the Wnt, TGF-beta, IFN, and TNF signalling pathways may be implicated in influencing and distinguishing their fate.

The diagnostic value of beta-catenin immunohistochemistry

beta-catenin is a 92-kDa protein that binds to the cytoplasmic tail of E-cadherin. It acts in the nucleus to stimulate cell proliferation and is degraded by complexing with the adenomatous polyposis coli gene. When it is mutated, it is ineffectively degraded and results in unchecked proliferative activity that plays a role in a subset of neoplasms. When there are alterations in beta-catenin degradation, it accumulates to a sufficient extent to be detected in the nuclei of tumor cells immunohistochemically, a feature that can be exploited in the differential diagnosis of selected neoplasms. Immunohistochemistry for beta-catenin may be useful in the differential diagnosis of selected tumors of soft tissue, the gastrointestinal tract, including the pancreas, lung, and female genital tract.

Familial adenomatous polyposis: experience from a study of 1164 unrelated german polyposis patients

The autosomal-dominant precancerous condition familial adenomatous polyposis (FAP) is caused by germline mutations in the tumour suppressor gene APC. Consistent correlations between the site of mutations in the gene and clinical phenotype have been published for different patient groups. We report our experiences of APC mutation analysis and genotype-phenotype correlations in 1166 unrelated polyposis families and discuss our results in the light of literature data. We show that the mutation detection rates largely depend on the family history and clinical course of the disease. We present a list of 315 different point mutations and 37 large deletions detected in 634 of the 1166 index patients. Our results confirm previously published genotype-phenotype correlations with respect to the colorectal phenotype and extracolonic manifestations. However, 'exceptions to the rule' are also observed, and possible explanations for this are discussed. The discovery of autosomal-recessive MUTYH-associated polyposis (MAP) as a differential diagnosis to FAP implies that some results have to be reinterpreted and surveillance guidelines in the families have to be reevaluated.

Inherited colorectal cancer syndromes

Colorectal cancer is one of the major causes of cancer deaths in both men and women. It is estimated that approximately 5% to 10% of patients with colorectal cancer have an inherited germline mutation that predisposes them to cancer. Clinically, hereditary colorectal cancer syndromes can be divided into those associated with colonic polyposis (familial adenomatous polyposis, attenuated familial adenomatous polyposis, and MYH-associated polyposis) and those not associated with colonic polyposis (hereditary nonpolyposis colon cancer). Treatment options for these patients include multiple aggressive screening regimens, chemopreventive medications, and prophylactic surgery. Selection of the appropriate management approach is best made using information obtained from the patient's clinical examination, the family medical history, and genetic evaluation. Compliance is improved when patients completely understand their disease and participate fully in the formulation of the treatment plan. Although not proved, it seems reasonable that this approach may prevent the poor outcomes so frequently associated with inherited cancer syndromes.

Nuclear beta-catenin expression distinguishes deep fibromatosis from other benign and malignant fibroblastic and myofibroblastic lesions

Deep fibromatoses (desmoid tumors) are clonal myofibroblastic proliferations that are prone to aggressive local recurrences but that do not metastasize. They must be distinguished from a host of fibroblastic and myofibroblastic lesions as well as from smooth muscle neoplasms. Virtually all deep fibromatoses have somatic beta-catenin or adenomatous polyposis coli (APC) gene mutations leading to intranuclear accumulation of beta-catenin. Since low-grade sarcomas in general lack beta-catenin and since reactive proliferations would not be expected to have it, we predicted that nuclear beta-catenin expression would be detected in deep fibromatoses but absent in other entities in the differential diagnosis. We evaluated the role of beta-catenin to help differentiate distinguish deep fibromatoses from congeners. Formalin-fixed, paraffin-embedded sections from 21 lesions from 20 patients with deep fibromatoses were stained with monoclonal beta-catenin antibody (Transduction Laboratories) and compared with low-grade fibromyxoid sarcoma (n=12), leiomyosarcoma (n=10), various other fibrosarcoma variants (n=13, including 3 myofibrosarcomas, 3 sclerosing epithelioid fibrosarcomas, 5 low-grade fibrosarcomas, 1 classic fibrosarcoma arising in dermatofibrosarcoma protuberans, 1 inflammatory myxohyaline tumor/myxoinflammatory fibroblastic sarcoma), myofibroma/myofibromatosis (n=12), nodular fasciitis (n=11), and scars (n=9). Nuclear and cytoplasmic staining was assessed. All 21 examples of deep fibromatosis displayed nuclear beta-catenin (focal nuclear staining in one case to 90% staining). All other lesions tested (n=67) lacked nuclear labeling for beta-catenin, showing only cytoplasmic accumulation. beta-Catenin immunohistochemistry separates deep fibromatosis from entities in the differential diagnosis, a finding that can be exploited for diagnosis. Most fibromatoses have diffuse nuclear staining although occasional examples only focally label.

Genetic testing for germline mutations of the APC gene in patients with apparently sporadic desmoid tumors but a family history of colorectal carcinoma

PURPOSE

Desmoid tumors, also known as aggressive fibromatosis, occur with an incidence of 10 to 15 percent in patients affected by familial adenomatous polyposis, an autosomal inherited disease caused by germline mutations in the APC gene. However, sporadic forms with no hereditary background exist. The aim of this study was to find out whether there are APC germline mutations in apparently sporadic desmoid tumor patients without clinical or familial signs of familial adenomatous polyposis but with a family history of colorectal carcinoma in at least one family member.

METHODS

Genomic DNA and mRNA were isolated from peripheral blood leukocytes of index patients of eight nonrelated families. Mutation screening was performed using reverse transcriptase polymerase chain reaction-based protein truncation test for APC exons 1-14. The large APC exon 15 was scrutinized by the protein truncation test of four overlapping genomic fragments. Additionally, genomic DNA from five desmoid tumors was analyzed for loss of heterozygosity at D5S346 close to the APC locus.

RESULTS

No translational stop mutations typical for familial adenomatous polyposis could be found in the APC gene in any of the analyzed blood samples from the desmoid tumor patients. Additionally, no loss of heterozygosity at D5S346 was found in four of five desmoids; one tumor was not informative.

CONCLUSIONS

These results may suggest that patients with sporadic desmoids and no clinical signs of familial adenomatous polyposis detected on careful examination, esophagogastroduodenoscopy, and complete colonoscopy do not need to be tested routinely for germline mutations of the APC gene. However, as large studies dealing with this problem are absent, it might be more time and cost effective to perform an APC mutational analysis instead.

Matrix Metalloproteinase Activity Modulates Tumor Size, Cell Motility, and Cell Invasiveness in Murine Aggressive Fibromatosis

Matrix metalloproteinases (MMPs) and tissue inhibitors of MMPs (TIMPs) regulate the degradation of extracellular matrix components and play important roles in the progression of select neoplastic processes. The locally invasive soft tissue tumor, aggressive fibromatosis (also called desmoid tumor), is caused by mutations resulting in beta-catenin-mediated T-cell factor (tcf)-dependent transcriptional activity. Because beta-catenin can regulate MMP expression, we investigated the expression of several MMPs and TIMPs in aggressive fibromatosis tumors that develop in Apc+/Apc1638N mice. Mmp-3 and Timp-1 were differentially regulated (5-fold and 0.5-fold, respectively) in tumors compared with normal fibrous tissue. Conditioned media from tumor cells showed an increased ability to degrade collagen, and inhibition of MMPs using GM6001 decreased the ability of the tumor cells to invade through Matrigel. Both the treatment of Apc/Apc1638N mice with GM6001 or crossing with a transgenic mouse that overexpresses Timp-1 resulted in a significant reduction in tumor volume. Surprisingly, overexpression of Timp-1 also resulted in a 50% increase in tumor number. Although TIMP-1 can induce growth stimulatory effects in some cell types, we found no difference in proliferation or apoptosis rate in cells from tumors that developed in the Timp-1-transgenic mice compared with mice that did not express the Timp-1 transgene, suggesting that TIMP-1 promotes aggressive fibromatosis tumor formation through an alternate mechanism. These data suggest that MMPs play a crucial role in regulating the invasiveness of mesenchymal cells and in modulating aggressive fibromatosis tumor progression. Because this is a locally invasive tumor, MMP inhibition could slow tumor growth and may prove to be an effective adjuvant therapy.

Genetic testing and phenotype in a large kindred with attenuated familial adenomatous polyposis

BACKGROUND & AIMS

An attenuated form of familial adenomatous polyposis has been described, but the phenotype remains poorly understood.

METHODS

We performed genetic testing on 810 individuals from 2 attenuated familial adenomatous polyposis kindreds harboring an identical germline adenomatous polyposis coli gene mutation. Colonoscopy was performed on mutation-positive persons.

RESULTS

The disease-causing mutation was present in 184 individuals. Adenomatous polyps were present in 111 of 120 gene carriers who had colonoscopy at an average age of 41 years. The median number of adenomas was 25 (range, 0-470), with striking variability of polyp numbers and a proximal colonic predominance of polyps. Colorectal cancer occurred in 27 mutation carriers (average age, 58 years; range, 29-81 years), with 75% in the proximal colon. The cumulative risk of colorectal cancer by age 80 was estimated to be 69%. An average of 3.4 recurrent polyps (range, 0-29) were found in the postcolectomy rectal remnant over a mean of 7.8 years (range, 1-34 years), with 1 rectal cancer.

CONCLUSIONS

This investigation shows that attenuated familial adenomatous polyposis in the kindreds examined shows a much smaller median number of polyps than typical familial adenomatous polyposis, a wide variability in polyp number even at older ages, and a more proximal colonic location of polyps and cancer, yet it is associated with an extremely high risk of colon cancer. The phenotype of attenuated familial adenomatous polyposis mimics typical familial adenomatous polyposis in some cases but in others is difficult to distinguish from sporadic adenomas and colorectal cancer, thus making genetic testing particularly important.

Comprehensive genetic and endoscopic evaluation may be necessary to distinguish sporadic versus familial adenomatous polyposis–associated abdominal desmoid tumors

BACKGROUND

There are limited data regarding how many patients with desmoid tumors actually represent cases with underlying familial adenomatous polyposis.

METHODS

A proband presenting with desmoid tumors and several of the family members underwent a detailed family history, genetic (adenomatous polyposis coli [APC] gene sequencing), and upper and lower endoscopic evaluation.

RESULTS

The proband's initial diagnosis was of a sporadic desmoid tumor. Colonoscopy was entirely normal. However, on subsequent esophagogastroduodenoscopy, several gastric polyps were found. The proband's mother subsequently underwent colonoscopy and was found to have multiple colon adenomas. On genetic analysis, a deletion of "T" was identified at codon 2645 of the APC gene in the proband. The proband's mother had a normal APC protein truncation test result. However, on full gene sequencing, the mother was found to harbor the same APC gene mutation.

CONCLUSION

A detailed family history and endoscopic and genetic evaluations for patients with desmoid tumors are vital because they may be the sentinel presentation of familial adenomatous polyposis. If confirmed in larger studies, APC full gene sequencing and upper and lower gastrointestinal tract evaluation may need to be part of standard evaluation of patients with abdominal desmoid tumors.