Desmoid fibromatosis, H&E stain. Banal fibroblasts infiltrate the adjacent tissue in fascicles. Mitoses may be infrequent.
Aggressive fibromatosis is a rare condition marked by the presence of desmoid tumors, which are benign, slow-growing musculoaponeurotic tumors without any metastatic potential. However, aggressive fibromatosis is locally aggressive. Despite their benign nature, they can damage nearby structures causing organ dysfunction. Most cases are sporadic, but some are associated with familial adenomatous polyposis (FAP). Approximately 10% of individuals with Gardner's syndrome, a type of FAP with extracolonic features, have desmoid tumors.
Histologically they resemble low-gradefibrosarcomas, but they are very locally aggressive and tend to recur even after complete resection. There is a tendency for recurrence in the setting of prior surgery; in one study, two-thirds of patients with desmoid tumors had a history of prior abdominal surgery.
Risk factors for desmoid disease amongst FAP patients include female sex, a 3' APC mutation, a positive family history and a history of previous abdominal surgery.
A 3' APC mutation is the most significant risk factor for intra-abdominal desmoid development amongst FAP patients. FAP patients presenting with an abdominal wall desmoid pre-operatively are at an increased risk of developing an intra-abdominal desmoid post-operatively.
Desmoid tumours of the breast are rare. Although benign, they can mimic breast cancer on physical examination, mammography and breast ultrasound and can also be locally invasive. Even though they occur sporadically, they can also be seen as a part of Gardner's syndrome. A high index of suspicion and a thorough triple examination protocol is necessary to detect rare lesions like a desmoid tumour which can masquerade as breast carcinoma. Desmoid tumour of the breast may present a difﬁculty in the diagnosis especially where imaging studies are not conclusive and suggest a more ominous diagnosis.
A biopsy is always indicated as the deﬁnitive method to determine nature of the tumour. Management of these lesions is complex, the main problem being the high rates of recurrence in FAP associated disease. Conversely, for intra-abdominal fibromatosis without evidence of FAP, although extensive surgery may still be required for local symptoms, the risk of recurrence appears to be lower. Wide surgical resection with clear margins is the most widely practiced technique with radiation, chemotherapy, or hormonal therapy being used to reduce the risk of recurrence.
Current experimental studies are being done with Gleevec (Imatinib) and Nexavar (sorafenib) for treatment of desmoid tumors, and show promising success rates.
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^Sinha A, Clark SK (2010). "Surgical prophylaxis in familial adenomatous polyposis: do pre-existing desmoids outside the abdominal cavity matter?". Fam Cancer9 (3): 407–11. doi:10.1007/s10689-010-9342-9. PMID20428953.
^Wilkinson MJ, Fitzgerald JE, Thomas JM, Hayes AJ, Strauss DC (2012). "Surgical resection for non-familial adenomatous polyposis-related intra-abdominal fibromatosis". BJS.99 (5): 706–13. doi:10.1002/bjs.8703. PMID22359346.