Desmoid-type fibromatosis involving the brachial plexus.

Desmoid-type fibromatosis involving the brachial plexus is a rare and challenging disease. Due to involvement of crucial neurovascular structures, wide local excision of the associated fibromas is rarely feasible and recurrence is common. The authors describe their experience in four surgically treated patients with desmoid-type fibromatosis involving the brachial plexus and review the relevant neurosurgical literature. All tumors were assessed for c-KIT oncogene mutations in hopes of establishing a biological basis for using the tyrosine kinase inhibitor imatimib mesylate as an adjuvant therapy. Three patients experienced tumor recurrence requiring reoperation. Fractionated radiotherapy achieved local control in three patients, and the disease in one patient progressed beyond the treatment field. Single base pair changes at exon 10 of the c-KIT oncogene were identified in three tumors. One tumor with this mutation did not respond to treatment with imatimib mesylate. A review of the literature revealed 17 additional patients in two different case series. Analysis of these cases emphasizes the need for careful resection in patients with desmoid-type fibromatosis and supports the conclusion that without adjuvant radiotherapy a high local recurrence rate can be anticipated. For optimal local disease control, the authors recommend postsurgical radiation therapy regardless of the extent of resection achieved. The mutational status of the c-KIT oncogene remains an intriguing biological marker that in the future may predict which lesions will be responsive to imatimib mesylate; larger series will be necessary to test this hypothesis.