(aggressive fibromatosis)

Annual incidence is estimated to be between 1/250 000 and 1/500 000. Rare in children. Soft tissue tumor which develops from support tissue and aponeuroses. It is made up of elongated cells resembling normal fibroblasts. This tumor does not metastasize but is very invasive and aggressive locally. Mutations of the CTNNB1 gene (3q21) coding for beta-catenin are found in about 85% of sporadic cases. In case of familial adenomatous polyposis or Gardner syndrome, it is associated with mutations of the APC tumor suppressor gene (5q21-q22) coding for the protein of the adenomatous colic polyposis. It can occur between 15 and 60 years of age, but appears frequently in early adolescence, and affects mainly women.

The tumor can be located in all parts of the body: involvement can be extra-abdominal (neck, shoulders, upper limbs, gluteal region), abdominal (from the fascia or the abdominal/chest wall), and more rarely intra-abdominal, at the level of the mesentery or the retroperitoneum. Depending on the location of the tumor, symptoms may include pain, fever, and functional abnormalities of the involved organ. It may also occur after surgical resections, typically after a C-section. The intra-abdominal form is commonly seen in association with the familial adenomatous polyposis or Gardner syndrome (see these terms).

Biopsy: abundant collagen surrounding fusiform elongated cells with small and regular nuclei and a clear cytoplasm. Immunohistological  exam reveals the expression of markers for muscle cells (such as actin, desmine, vimentin) and the absence of CD34. Complete surgical resection is the best treatment. Non-surgical treatments include radiation therapy, anti-estrogen, NSAIDS, chemotherapy (methotrexate, vinblastine/vinorelbine, pegylated liposomal doxorubicin) or inhibitors of the tyrosine kinase (imatinib, sorafenib). Due to a variable and often unpredictable evolution of the tumor, a period of observation is recommended for asymptomatic patients. As the disease is often recurrent (local relapse in about 70 % of cases), a strategy of surveillance every 3 to 6 months is essential. The prognosis depends on the type of the tumor. Life expectancy is normal for  abdominal and extra-abdominal tumors.

Anesthetic implications:

according to the location of the tumor

References:        

Updated: December 2017