Role of tumor-associated macrophages and angiogenesis in desmoid-type fibromatosis.

Desmoid-type fibromatosis (DTF) is a rare soft tissue tumor with fibroblastic features affecting two to four individuals per million population per year. Despite its bland microscopic appearance, the tumor behaves aggressively. Although unable to metastasize, DTF tends to recur and local recurrences in anatomically critical sites can be fatal. Tumor-associated macrophages (TAM) play an important role in tumor development through the activation of angiogenesis, particularly in cases of epithelial malignancies. The aim of this study is to investigate the prognostic significance of TAMs and the number of microvessels in DTF. Tumor macrophages (CD163), microvessel density (CD31), and beta-catenin were investigated on 69 primary DTF cases with follow-up information. CTNNB1 mutations were also studied. High density of tumor macrophages and high number of microvessels were associated with a significantly worse recurrence-free survival (P = 0.03 and P = 0.007, respectively). There was a significant correlation between microvessel density and CD163 macrophages (P = 0.02). Furthermore, combination of high number of tumor macrophages and high microvessel density greatly improved the statistical significance (P = 0.000005). Macrophages and microvessels may play an important role in the biologic behavior of DTF. This finding could help in the clinical management of patients with DTF.