Desmoid fibromatosis: Immunohistochemical analysis of 14 cases on tissue microarray (TMA)

Background/aim: Desmoid fibromatosis are rare, benign but locally aggressive tumors, characterized by an infiltrative growth and a tendency towards local recurrence, but an inability to metastasise. The morphological diagnosis may be difficult, requiring immunohistochemistry. The aim of our study is to determine the im munohistochemical phenotypes of these tumours to evaluate if they are helpful and to define a diagnostic strategy. Methods: Immunohistochemistry was used to examine the expression of β-catenin, APC protein, in archival material derived from fourteen cases of extraabdominal desmoid tumors. Desmoids specimens were assembled into a clinical data-linked tissue micro - array. Nuclear β-catenin expression was observed in 100% of the specimens. Positive cytoplasmic staining for APC protein was found in 11 of 14 (78,6%). But all samples were negative for oestrogen and progesterone receptors, c-KIT and WT1. Results: Our results regarding β-catenin and APC confirm the previous findings that those proteins play a crucial role in the pathogenesis of sporadic aggressive fibromatosis. © 2010 Springer Verlag France.