Desmoid-type fibromatosis-associated Gardner fibromas: prevalence and impact on local recurrence.

Although Gardner fibroma is a precursor lesion of desmoid tumor, the prevalence and prognostic importance of Gardner fibroma associated with desmoid tumors has not been systematically studied in adults. From 129 patients with desmoid-type fibromatosis, 170 specimens were re-examined for the presence of an associated Gardner fibroma. Clinicopathologic features of Gardner fibroma-associated desmoid-type fibromatosis were compared to desmoid tumors without associated Gardner fibroma. Recurrence-free survival was compared using multivariate Cox proportional hazard regression to account for known confounding factors. Of 104 evaluable primary desmoid tumor resections, 25 (24%) had an associated Gardner fibroma. When previous incisional biopsies and resection specimens of locally recurrent desmoid tumors were also examined, the overall prevalence of associated Gardner fibroma was 37%. Desmoid tumors arising in high risk anatomic sites (extremities or deep soft tissues of the back and chest wall) were more often associated with Gardner fibroma than tumors at other sites. Median recurrence-free survival for patients with Gardner fibroma-associated desmoid-type fibromatosis was 3.2 years, whereas median survival for patients without associated Gardner fibroma was >25 years (hazard ratio 2.8; P = 0.001). Although the presence of Gardner fibroma had no impact on the recurrence rate of desmoid tumors arising at high risk anatomic sites, associated Gardner fibroma increased the risk of recurrence 4-fold for desmoid tumors at low risk anatomic sites. Associated Gardner fibroma is under-recognized in desmoid-type fibromatosis and increases the risk of local recurrence for a subgroup of patients.