Background: Desmoid-type fibromatosis is a locally aggressive tumor known to have high potential for local recurrence after resection, while it exhibits self-limiting behavior and shows growth arrest or spontaneous regression in many patients. Thus, its natural course is not well known, and the proper treatment has not yet been established.
Methods: We retrospectively reviewed clinical outcome and changes in tumor size in 11 consecutive patients with extremity and trunk desmoid-type fibromatoses, who were basically observed without any treatment after diagnosis.
Results: For two patients in whom the tumors were initially incorrectly diagnosed as other tumors, surgical resection was performed. For another two patients, surgical resections were performed in the follow-up periods due to tumor enlargement or joint contracture. In all four patients who underwent surgery, tumors recurred shortly after resection and re-resection was not performed. During the follow-up periods with a median length of 56 months, ten tumors eventually stopped growing, and three of them regressed spontaneously. At the time of final follow-up, ten patients were alive with residual disease without severe morbidity. In one patient, the tumor enlarged to over 30 cm in diameter with a substantial functional deficit.
Conclusions: Simple observation is a noninvasive and function-preserving treatment for desmoid-type fibromatosis.