Chromosome changes in desmoid tumors developed in patients with familial adenomatous polyposis

Chromosomal and methylation alterations in sporadic and familial adenomatous polyposis-related duodenal carcinomas

Primary carcinomas of the small intestine are rare and the mechanism of their pathogenesis is poorly understood. Patients with familial adenomatous polyposis (FAP) have a high risk of developing duodenal carcinomas. The aim of this study is to gain more insight into the development of duodenal carcinomas. Therefore, five FAP-related duodenal carcinomas were characterized for chromosomal and methylation alterations, which were compared to those observed in sporadic duodenal carcinomas. Comparative genomic hybridization (CGH) and methylation-specific multiplex ligation-dependent probe amplification (MS-MLPA) was performed in 10 primary sporadic and five primary FAP-related duodenal carcinomas. In the FAP-related carcinomas, frequent gains were observed on chromosomes 8, 17 and 19, whereas in sporadic carcinomas they occurred on chromosomes 8, 12, 13 and 20. In 60% of the sporadic carcinomas, gains in the regions of chromosome 12 were observed which were absent in the FAP-related carcinomas (P=0.04). Hypermethylation was observed in the immunoglobulin superfamily genes member 4 (IGSF4), TIMP metallopeptidase inhibitor 3 (TIMP3), Estrogen receptor 1 (ESR1), adenomatous polyposis coli (APC), H-cadherin (CDH13) and paired box gene 6 (PAX6) genes. Hypermethylation of PAX6 was only observed in FAP-related carcinomas (3/5) and not in sporadic carcinomas (P=0.02). In conclusion, in contrast to sporadic duodenal carcinomas, gains on chromosome 12 were not observed in duodenal carcinomas of patients with FAP. Identification of the genes in these regions of chromosome 12 could lead to a better understanding of the carcinogenesis pathways leading to sporadic and FAP-related duodenal carcinomas. Furthermore, hypermethylation seems to be a general feature of both FAP-related duodenal carcinomas as well as sporadic duodenal carcinomas with the exception of the PAX6 gene, which is methylated only in FAP-related carcinomas.

Desmoid tumour in familial adenomatous polyposis. A review of literature

Desmoid tumours (DT) are rare benign tumours that do not metastasise, but tend to invade locally. DT are frequently seen in patients with familial adenomatous polyposis (FAP), and diagnosis and treatment are often difficult. Surgical trauma, genetic predisposition and hormonal factors are considered to be correlated with the development and growth of DT. In patients with FAP, 50% of the tumours are localised intra-abdominally, and 85-100% of these are mesenteric. DT frequently present as non- tender, slowly growing masses. The symptoms are abdominal pain, vomiting, diarrhoea or haematochezia. Mesenteric DT can cause small bowel obstruction or ischaemia, hydronephrosis or form fistulas. Diagnosis is obtained through biopsy and the extension is determined by a CT-scan. Surgical excision is recommended in patients with DT in the abdominal wall. First line treatment of mesenteric DT is a NSAID in combination with tamoxifen. Surgery may be considered in case of a small and well-defined DT with no signs of invasion of vital structures, and in cases of imminent bowel ischaemia or obstruction. The prognosis in mesenteric DT is serious, and improvement of the therapeutic strategy awaits current international studies.

Desmoid tumour: a pleomorphic lesion

BACKGROUND

Desmoid tumour (DT) is an uncommon locally invasive non-metastasizing neoplastic lesion. The aetiology of this tumour is unknown and its treatment is controversial. Twelve cases of DT are presented and the literature is reviewed.

METHODS

Twelve cases of DT treated at our institution during a 3.5-year period are analysed and the literature reviewed. Ten patients were referred with a primary tumour, one with local recurrence and one patient with a second primary desmoid tumour. One patient had multiple mesenteric DT (familial adenomatous polyposis coli-FAP), and in the remaining 11 patients the tumour was located in the abdominal wall in four, at an extremity in three, in the upper back in two patients, in the pelvis in one and retroperitoneally in one.

RESULTS

The largest mesenteric DT was marginally excised en bloc with total jejunectomy. In the remaining 11 DT, complete excision to microscopically tumour-free margins was possible in nine cases and to microscopically involved margins in two cases. At a mean follow-up of 22 months (range 7-38 months), one patient was alive with stable disease (Gardner's syndrome), 10 patients were alive and free of recurrence and one patient (9%) developed local recurrence which was re-excised-she is disease-free 10 months later.

CONCLUSIONS

Complete excision is the main modality of treatment for primary and recurrent DT. This is feasible in most cases except for tumours involving the base of the bowel mesentery. Surgical resection alone achieved local control of the tumour in most of the patients in this series (92%).

Trisomies 8 and 20 characterize a subgroup of benign fibrous lesions arising in both soft tissue and bone

Trisomy 8 and trisomy 20 are nonrandom aberrations in desmoid tumors. The presence of these trisomies in related benign fibrous lesions of bone has not been previously addressed. In this study, 22 specimens from 19 patients diagnosed with desmoid tumor, desmoplastic fibroma, periosteal desmoid tumor, osteofibrous dysplasia, or fibrous dysplasia were examined by cytogenetic analysis of short-term cultures and bi-color fluorescence in situ hybridization of cytological touch preparations or paraffin-embedded tissue with centromeric probes for chromosomes 8 and 20. Trisomy 8 and trisomy 20 were detected by molecular cytogenetic methodologies in 15 specimens, including 10 primary bone lesions. Traditional cytogenetic analysis revealed trisomy 8 in two cases of osteofibrous dysplasia. Our findings demonstrate that trisomy 8 and trisomy 20 are also nonrandom aberrations in histologically similar, but clinically distinct, benign fibrous lesions of bone.

Identification and progression of a desmoid precursor lesion in patients with familial adenomatous polyposis

BACKGROUND

Desmoid tumours occur in about 10 per cent of patients with familial adenomatous polyposis (FAP), and are an important cause of morbidity and death. The natural history of desmoids was investigated by documenting prospectively the prevalence and progression of possible precursor lesions.

METHODS

A group of patients with FAP and controls were examined at laparotomy. Another group, with FAP and no clinical evidence of desmoid, and a group of controls, underwent abdominopelvic computed tomography.

RESULTS

At laparotomy 13 of 42 patients with FAP had fibromatous mesenteric plaques; seven of these had not had surgery. Seven had more extensive mesenteric fibromatosis and had undergone significantly more laparotomies than the rest. Of 103 patients scanned, two had desmoid tumours and 22 (21 per cent) had mesenteric fibromatosis. On follow-up both desmoid tumours grew rapidly; mesenteric fibromatosis was unchanged in eight and resolved in four of the 12 patients rescanned.

CONCLUSION

A model of desmoid tumour development is suggested, analogous to the adenoma-carcinoma sequence, in which a less benign phenotype emerges as molecular genetic abnormalities accumulate: mesenteric plaque-like desmoid precursor lesions arise in many patients with FAP before surgery as a result of abnormal fibroblast function; some, perhaps stimulated by surgery, progress to mesenteric fibromatosis; these in turn can give rise to desmoid tumours.

Trisomies 8 and 20 in desmoid tumors

A nonrandom occurrence of trisomy 8 and of trisomy 20 in desmoid tumors has been recently reported. The finding of trisomy 8 in nondividing desmoid tumor cells by in situ hybridization prompted us to evaluate, in a similar way, the occurrence of trisomy 20 and the possible occurrence of both trisomies together because their co-existence was cytogenetically observed in a few cases. Double fluorescence in situ hybridization (FISH) with centromeric probes for chromosomes 8 and 20 was performed on 16 single cell suspensions of desmoid tumors. FISH confirmed the occurrence of trisomy 8 or 20 in a single cell suspension of desmoid tumors. Both individual trisomies, and even more their association in the same cells, are rare to extremely rare in solid tumors in general and in mesenchymal tumors in particular, and are only known to occur in infantile fibrosarcoma.

Desmoids in familial adenomatous polyposis

Clinical desmoid disease affect approximately 10 per cent of patients with familial adenomatous polyposis (FAP); the subclinical rate is unknown. Desmoids are probably neoplastic rather than regenerative in origin and may arise in association with germline or somatic mutations at or beyond codon 1444 of the APC gene. Intra-abdominal desmoids behave unpredictably but are an important cause of death in those with FAP. Signal intensity on magnetic resonance imaging reflects tumour cellularity, which in part determines progression, and this may help management. Surgical treatment of advanced desmoids is hazardous, but medical treatments have limited success. Chemotherapy with doxorubicin and dacarbazine is currently under evaluation.

Chromosome aberrations in desmoid tumors. Trisomy 8 may be a predictor of recurrence

Cytogenetic analyses of short-term cultures revealed clonal chromosome aberrations in 6 of 13 desmoid tumors. These aberrations included two consistent events, trisomy 8 (n = 4) and trisomy 20 (n = 3), which have not been reported previously in desmoid tumors. Because trisomy 8 was found in two recurrent desmoid tumors, we used fluorescent in situ hybridization (FISH) methodology to evaluate chromosome 8 in 25 paraffin-embedded and frozen desmoid specimens. The FISH studies demonstrated that both patients with cytogenetic trisomy 8 at the time of recurrence also had had trisomy 8 in primary tumors 4 years earlier. The proportion of trisomy 8 cells in these cases did not change substantially between original diagnosis and recurrence. The FISH studies also revealed trisomy 8 in one recurrent desmoid tumor which had been cytogenetically unremarkable and revealed trisomy 8 in one recurrent desmoid that had not been karyotyped. Four of six patients with trisomy 8 had been followed for more than 1 year, and the desmoid tumors in each of these 4 patients recurred. By contrast, recurrence was noted in only 2 of 17 patients whose desmoid tumors lacked trisomy 8. Our findings demonstrate that trisomy 8 and trisomy 20 are nonrandom aberrations in desmoid tumors. Trisomy 8 appears to be associated with an increased risk of recurrence.

Deletion (5q) in a desmoid tumor of a patient with Gardner's syndrome

Desmoid tumors are associated with as many as 20% of cases of familial adenomatous polyposis (FAP) and Gardner's syndrome. In the present study, four specimens from different regions of a massive intraabdominal desmoid tumor from a 23-year-old white male with Gardner's syndrome were analyzed cytogenetically. Two different clonal abnormalities were observed. Two of the four specimens analyzed showed a del(5)(q14q31), which involves the region q21-->22 where the familial adenomatous polyposis gene is localized. In the two other specimens, a balanced translocation involving chromosomes 3 and 4 and an inv(4) was detected. Our findings confirm previous reports about the importance of chromosome defects on 5q in development of desmoid tumors, particularly in patients with Gardner's syndrome.

Familial adenomatous polyposis coli and clear cell sarcoma of the kidney

Familial adenomatous polyposis coli is an inherited multiple neoplasia syndrome that is associated with an increased risk for development of another primary tumor. We report a case of a 14-year-old boy who had a proctocolectomy for familial adenomatous polyposis coli. He had survived radical nephrectomy, chemotherapy, and radiotherapy for a congenital clear cell sarcoma of the right kidney. Perhaps the presence of the familial adenomatous polyposis gene induces chromosomal instability in affected persons.