Fibromatosis

Desmoid tumor derived from myofibroblast cells in musculoaponeurotic structures
- Often arise from scars in skeletal muscle, and then proceed to infiltrate adjacent muscles
- Infiltration often causes muscle breakdown, palpable firmness on physical examination (without skin involvement)
Benign histologically, but often appear infiltrative and locally aggressive on imaging studies
High rate of recurrence
No specific gene mutation associated with sporadic desmoid tumors, although increase seen in familial adenomatous polyposis (also known as Gardner syndrome)
- Adenomatous polyposis coli (APC) gene on chromosome 5 has point mutations in Gardner syndrome, and 10-15% of patients have desmoid tumors ¹
- Desmoid tumors have APC mutations, which may be spontaneous ²
Desmoid tumors may also have endocrine component; often regress during menopause or hormone treatment (including use of oral contraceptives)³
More common in females
Most common in adults in second through fifth decades of life
Most common locations: anterior abdominal wall and shoulder girdle (although retroperitoneal tumors are common in patients with Gardner syndrome ⁴
- In abdominal neoplasms, patients may complain of swelling or problems from visceral compression; in extremity neoplasms, complaint is often gradual limb swelling
MRI most useful for following desmoid tumors due to its superior delineation of soft tissue anatomy ⁵
- May also be used to follow patients post-operatively for recurrence, which occurs in up to 70% of cases
Tumors must be biopsied for diagnosis, and histology shows abundant collagen surrounding poorly circumscribed bundles of spindle cells with regular nuclei and pale cytoplasm
Treatment: Wide resection with negative surgical margins; positive margins associated with high risk of recurrence ⁶
- Radiation used for recurrence or where surgical resection is not possible
- Chemotherapy may also be used for recurrence: doxorubicin, dacarbazine, carboplatin ⁷

References

1. Klemmer S, Pascoe L, DeCosse J. Occurrence of desmoids in patients with familial adenomatous polyposis of the colon. Am J Med Genet. Oct 1987;28(2):385-92.

2. Sturt NJ, Gallagher MC, Bassett P, Philp CR, Neale KF, Tomlinson IP, et al. Evidence for genetic predisposition to desmoid tumours in familial adenomatous polyposis independent of the germline APC mutation. Gut. Dec 2004;53(12):1832-6.

3. Wilcken N, Tattersall MH. Endocrine therapy for desmoid tumors. Cancer. Sep 15 1991;68(6):1384-8.

4. Raynham WH, Louw JH. Desmoid tumours in familial polyposis of the colon. S Afr J Surg. Jul-Sep 1971;9(3):133-40.

5. Lee JC, Thomas JM, Phillips S, Fisher C, Moskovic E. Aggressive fibromatosis: MRI features with pathologic correlation. AJR Am J Roentgenol. Jan 2006;186(1):247-54.

6. Buitendijk S, van de Ven CP, Dumans TG, den Hollander JC, Nowak PJ, Tissing WJ, et al. Pediatric aggressive fibromatosis: a retrospective analysis of 13 patients and review of literature. Cancer. Sep 1 2005;104(5):1090-9.

7. Bhama PK, Chugh R, Baker LH, Doherty GM. Gardner's syndrome in a 40-year-old woman: successful treatment of locally aggressive desmoid tumors with cytotoxic chemotherapy. World J Surg Oncol. Dec 17 2006;4:96.