fibromatosis

Fibromatosis refers to a group of disorders characterized by the abnormal proliferation of fibrous tissue in soft tissues, fascia, or skin. The lesions are benign and do not metastasize, but they can be locally aggressive and recur after treatment. Fibromatoses are broadly divided into deep (desmoid-type fibromatosis) and superficial forms, with additional pediatric variants such as infantile myofibromatosis.

Desmoid-type fibromatosis is the best-known deep form. It can occur anywhere, most often in the abdomen, limbs, or trunk. Desmoids may be sporadic or associated with familial adenomatous polyposis (FAP) or CTNNB1 gene mutations, both involving the beta-catenin signaling pathway. Superficial fibromatoses include palmar fibromatosis (Dupuytren’s contracture) and plantar fibromatosis (Ledderhose disease), which affect the hands and feet and usually cause contractures or nodules without aggressive tissue invasion. Infantile myofibromatosis occurs in infancy and can involve skin, muscle, bone, or viscera; many lesions regress spontaneously, but visceral involvement can be serious.

Diagnosis is based on clinical features, imaging (notably MRI to assess extent and relation to surrounding structures), and histology. Biopsy shows bland spindle cells with abundant collagen; nuclear beta-catenin positivity supports desmoid-type fibromatosis.

Treatment aims to control symptoms and function while minimizing morbidity. Some small, asymptomatic tumors are observed. For others, management may include surgical excision with clear margins, radiotherapy for unresectable or recurrent disease, and systemic therapies such as nonsteroidal anti-inflammatory drugs, hormonal therapy, or targeted agents. Desmoid tumors have a high risk of local recurrence, but overall prognosis is favorable, as they do not spread to distant sites.